Water.dist.Full.manual.V8i
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Bentley WaterCAD/GEMS, Water Distribution Design and Modeling, Full...
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Bentley WaterCAD/GEMS, Water Distribution Design and Modeling, Full Version V8i
TRN012650-1/0001
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Patents United States Patent Nos. 5,8.15,415 and 5,784,068 and 6,199,125.
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Bentley WaterCAD/GEMS, Water Distribution Design and Modeling, Full Copyright © December-2008 Bentley Systems Incorporated
2
Bentley WaterCAD/GEMS Water Distribution Design and Modeling, Full
Day 1 8:30
Day 2 Registration and Check-in Welcome and Announcements
8:30
Hydraulic Review • Basic Working Equations • Units of Pressure and Flow • Solution Methods
8:30
12:00
Lunch
Water Quality Modeling • Why Model Water Quality? • Use of Models • Transport/Kinetics • Initial Conditions • Tracers • Water Quality Calibration • Design/Operation for Water Quality • Tanks and Reservoirs • Chlorine Modeling
Workshop 4 – System Design Improvements - Plan, Develop and Implement a system improvement strategy and compare design costs using WaterCAD’s new cost manager.
Lunch Workshop 1 – Building a Network with Fire Flow - Construct/Solve a basic network Other Pressure Network Components • Pumps − Representation in Model − Generating System Head Curves − Variable speed pumps • Regulating Valves 4:30 − Pressure Reducing Valves − Flow Control Valves − Pressure Sustaining Valves − General Purpose Valves − Flow Emitters
Fire Protection • Needed Fire Flow • Insurance Ratings • Sprinkler System Design Workshop 5 – Automated Fire Flow Analysis - Calculating fire flows for a subset of a distribution system
12:00
Q & A Session / Adjourn
Criticality Analysis • Isolating valves • Distribution segments • Critical segments Workshop 8 – Analysis of Valving and Critical Segments - Find the critical places in your system which you can easily fix.
Q & A Session / Adjourn 4:30
Dec-08
Lunch Workshop 7 – Multisource Mixing, Chlorine Residual, Age and Trace Analysis – Run several water quality analyses on an existing water model.
Workshop 2 – Building a Network with Pumps, Tanks and PRVs Analyze various system scenarios with pumping, minor losses, check valves and reducing valves. 4:30
Extended Period Simulations • Demand Schedules and Patterns • Data Collection • Logic Based Controls • Hydropneumatic Tank modeling • Tank modeling during EPS • Energy costing Workshop 6 – Variable-Speed Pumping and Energy Costing Analysis - Analyze the system's response under time variable conditions focusing on VSPs, logic based controls, advanced graphing, topological alternatives, and energy costs.
Planning System Improvements • Establishing Pressure Zones • Pipe Sizing • Pump Selection and Sizing • Storage
Demonstration of WaterCAD Basics 12:00
Model Calibration • Where Do You Go for Data? • What Do You Adjust and When? • Identifying Bad Data Workshop 3 – Steady State Calibration of Field Measurements Applying Calibration Techniques Using WaterCAD
How to Apply Models • What Data Do You Need? • How to Get the Data • Assessing Level of Detail • Defining Modeling Objectives Defining Network Models • Basic Network Components − Pipes/Junctions/Boundary − Conditions − Alternative topologies
Day 3
Copyright © 2008 Bentley Systems Incorporated
Q & A Session / Adjourn
Agenda
Bentley WaterCAD/GEMS Water Distribution Design and Modeling, Full
Day 5
Day 4 8:30
Transient Analysis • Basics of Transient Analysis • Demonstration of Hammer for Transient Analysis
Flushing – UDF and Conventional Methods • Using fire hydrants as flushing components
Automating Calibration • Grouping Pipes • Entering Field Data • Calibration Optimization
Workshop 12 – Developing System Flushing Routines 4:30
8:30
ModelBuilder • Nature of GIS Data • Setting up Connections • Options and Settings
Q & A Session / Adjourn
Workshop 9 – Automating Calibration using Darwin Calibrator - Automatically design pipes using genetic algorithms
Workshop 13 – Automating Model Building using ModelBuilder Creating a model from data
Automating Design • Design Optimization Methods • Leakage Detection • Sizing New Pipes vs. Rehabilitating Pipes • Setting-up Design Events • Setting-up Design Groups • Using Results of Darwin Designer
12:00 Lunch LoadBuilder • Sources for Loading Data • Loading Data Formats – Points, Polygons • Meter Aggregation • Flow Distribution • Thiessen Polygons • Need for Thiessen Polygons
Workshop 10 – Automating Design using Darwin Designer Automatically design pipes using genetic algorithms
Workshop 14 – Automating Demand Allocation using LoadBuilder Importing demand data from meter data and population data
12:00 Lunch Automating Skeletonization • Types of Skeletonization − Pipe Removal − Branch Trimming − Series Removal − Parallel Removal • Protecting Elements • Conditions and Settings • Using Results of Skelebrator
TRex • Explaining DEMS, Projections, Units and GIS Grinds • Spatial Referencing • Units • Selection Sets • Saving Results Workshop 15 – Importing Elevations using TRex Importing elevations from raster grid
Workshop 11 – Skeletonizing a Large Model using Skelebrator Interoperability is Driving the Future of Modeling • Available Platforms, Pro’s & Cons of each, demonstrations - Stand Alone - MicroStation - AutoCAD - ArcGIS • Bentley Water – GIS for Water Distribution Systems - Asset Management - Map assessment and inventory
Dec-08
Basic Geospatial Data Concepts • Understanding Modeling Data • Geospatial data • WaterGEMS Toolbar
WaterObjects.net • Extending Modeling Capabilities • Pre-processing data • Post-Processing Data 4:30
Copyright © 2008 Bentley Systems Incorporated
Q&A Session/Adjourn
Agenda
Introduction
Page 0-1
What’s new in V8i? Bentley WaterCAD V8 XM/V8i Bentley WaterGEMS V8 XM/V8i
Introduction • Major release from Bentley’s Haestad Solution Center • All-new technology • Free for SELECT subscribers
Bentley’s Haestad Solution Center - Watertown, CT -
• Upgrade pricing available
What’s V8 all about? Speed Interoperability Usability New features
Designed to support all-pipe models The only truly interoperable model in the market Easier than ever (believe it or not!) Dozens of new features to maximize your ROI
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Introduction
Page 0-2
A Commitment to Interoperability
XML aecXML XMpLant TransXML GML DWG
WaterCAD & WaterGEMS
WaterGEMS V8 XM Edition
ArcGIS platform
WaterCAD V8 XM Edition
Windows Stand-alone MicroStation platform AutoCAD platform
LoadBuilder Terrain Extraction (TRex)
Included
ModelBuilder
Available
Darwin Calibrator
Add-ons
Darwin Designer Skelebrator
HAMMER and SCADAConnect – Available Add-on
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Introduction
Page 0-3
V8 in a nutshell • New Hydrants element type • New VSP battery element type • Calibration & Leakage Detection • New Isolation valve element type • Criticality analysis • Fire Flow navigator • Pressure dependent demands • Network trace • Demand control center • Select by polygon
WaterCAD V8 XM Edition
Easy-to-use Interface •
Stand-alone interface
•
MicroStation interface
•
AutoCAD interface (add on)
•
Multi background-layer support
•
CAD, GIS & Database
•
Unlimited undo and redo
•
Scaled, schematic & hybrid environments
•
Element morphing, splitting & reconnection
•
Element prototypes
•
Aerial view and dynamic zooming
•
Named views
Copyright © 2008 Bentley Systems Incorporated
WaterGEMS V8 XM Edition ArcGIS interface shown
Dec-08
Introduction
Page 0-4
Criticality Analysis • Find distribution segments based on valving • Identify segments which are large or have many isolating valves • Identify outages that will interfere with service • Identify impact of outages • Determine where valves are needed
V8 GIS-type Features • LoadBuilder (stand-alone) • TRex (stand-alone) • ModelBuilder (stand-alone)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Introduction
Page 0-5
More highlights • Better HAMMER integration • Improved hydropneumatic tank modeling • New flushing routine • Only in SELECT upgrade 3
File Types
Stand Alone (xxx.dwh)
HMI Modeling Data (xxx.wtg.mdb)
MicroStation (xxx.dgn)
Copyright © 2008 Bentley Systems Incorporated
AutoCAD (xxx.dwg)
Graphics Data (xxx.wtg)
ArcGIS (xxx.mdb)
Dec-08
Introduction
Page 0-6
Earlier Versions Version 7 (3) wcd
Update wcd
Export Presentation Settings xml Import Presentation Settings
Version 8
wtg
Pre-version 7 Export GEMS Dataset
mdb
Import
wtg.mdb
SELECT Benefits • Network License • 24 x 7 Technical Support – Live Meeting Assistance
• New versions! Plus updates • Access to KnowledgeBase • Home-use license
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Introduction
Page 0-7
Bentley Institute • Anytime, any place training to maximize productivity for busy people • eLearning, classroom learning, distance learning • Many purchasing options, including unlimited training • All training tracked and managed on Bentley LEARN Server “We found our custom workflow training approach that Bentley helped institute gets our users into a productive mode much faster than with our previous program.” – George Brashear, Indiana DOT
Which version of WaterCAD/GEMS do I download? Select Upgrade 2 08.09.165.12
• MicroStation 8.9.3 • AutoCAD 2004, 2005, 2006 • ArcGIS 8.3, 9.0, 9.1, 9.2 • Does not have HAMMER, flushing
Select Upgrade 3 08.09.400.34
• MicroStation 8.9.4 • AutoCAD 2008 (2007) • ArcGIS 9.2 (9.1)
Select Upgrade 4 (V8i) 08.11.00.29
• MicroStation V8i • AutoCAD 2009 (2008) • ArcGIS 9.3
– Does not matter if you use stand-alone – Files are not backward compatible
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Introduction
Page 0-8
The End Enjoy the new features of V8 XM/V8i
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-1
Modeling Fundamentals What is a good Model?
Hydraulics Review Principles Minor Losses
Flow
Solution Methods
Velocity
Head Loss
Pressure
Energy
Copyright © 2008 Bentley Systems Incorporated
Continuity
Dec-08
Hydraulics Review
Page 1-2
Quiz: Types of Flow • Compressible vs. Incompressible? • Laminar vs. Turbulent? • Single Phase vs. Multi-Phase? • Closed Pipe vs. Open Channel? • Full pipe vs. Partly Full? • Newtonian vs. non-Newtonian?
Types of Applications • Water distribution • Raw water supply • Pressure irrigation • Fire protection • Sewage force mains • Cooling water • Industrial applications
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-3
Flow • Volume/time • m3/s – cubic meters/second (SI) • L/s – liters/second • m3/hr – cubic meters/hour • ft3/s – cubic feet/second (FPS) • gpm – gallons/minute • MGD – million gallons/day • ac-ft/day – acre-feet/day • cufr/frtnt – cubic furlongs/fortnight
Velocity Velocity = Flow / Area
V = Q/A
• Common Units: – m/s = meters per second – fps = feet per second – 1 m/s = 3.28 ft/s
• What is the correct range? High? Low? – – – –
1 ft/s typical (0.6 – 1.2 m/s) 5 ft/s high (1.5 – 2.5 m/s) 10 ft/s very high (>3.0 m/s) 0.1 ft/s residential (.05 m/s)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-4
Velocity May also be expressed in terms of pipe diameter:
Q = kVD 2 where
Q
= flow
V
= velocity
D
= diameter
k
= unit conversion factor
Values for “k” in V = Q / k D2 English units (V in ft/s): Q
Diameter (in.) Diameter (ft.)
CFS
0.00545
MGD
0.00354
0.510
gpm
2.44
352
0.785
Metric units (V in m/s): Q
Diameter (m) Diameter (mm)
m3/s
0.785
7.85x10-5
L/s
785
0.0785
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-5
Pressure • Force/Area • Newton/m2- Pascal (SI) • kPa – Kilo Pascal • bar – 100 kPa • psf – pound/ft2 (FPS) • psi – pound/in2 (US typical) • atm – atmosphere (14.7 psi / 10.33 mca) • Gage vs. absolute • pound?
Pressure • Pressure at base of column = height a liquid (water or mercury) in column – ft or m water or in or mm mercury
Does the diameter matter? 46 ft Force? 20 psi 1 psi = 2.31 ft
46 ft Force?
? psi
Copyright © 2008 Bentley Systems Incorporated
20.4 m Force? 200 kPa 1 kPa = 0.102 m
Dec-08
Hydraulics Review
Page 1-6
Pressure Standards • Minimum – 20 psi (15 m H20)
• Minimum normal – 20, 25, 30, 35, 40 psi (20, 25, 30 m H20)
• Maximum – 80, 100, 125, 150? Psi (40 …60 m H20)
Continuity Principle Conservation of mass: Mass in = Mass out • For steady incompressible flow: – net flow into junction = use at junction.
Q = U i
Where: Qi = flow in ith pipe into junction U = usage at junction
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-7
Continuity in Tanks • For unsteady state conditions, water stored in tanks: – sum of the inflows (minus outflows) = change in storage
NetQ = Qi − U = A Where:
H A t Q U
= = = = =
dH ΔH =A dt Δt
water level in tank tank cross-sectional area time flow (positive is inflow and negative is outflow) usage directly from tank
Energy Principle • In hydraulics, energy converted to energy per unit weight (ft-lb/lb) of water, reported in length units (ft) called “head”. • 3 forms of energy: – (1) – (2) – (3)
where:
Pressure Velocity Elevation p γ V g z
= = = = =
- p /γ - V2 / 2g -z
(usually negligible)
pressure specific weight of fluid velocity gravitational acceleration elevation
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-8
Hydraulic Head • HGL = Hydraulic Grade Line • Static Head = Elevation + Pressure Head = HGL • Total Head = Static Head + Velocity Head • Head Loss = difference in head between points
Fluids move from high head to low head
Flow from Higher to Lower Head Point A
Point B
Point C
HGL
Point D
Head Loss
2.31p Direction of Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-9
Head Loss Equations • Empirical relationships in turbulent flow • Darcy Weisbach – Colebrook White – Swamee Jain
• Hazen Williams • Manning
Darcy-Weisbach h = f
LV 2 D2 g
h = head loss
ƒ
=
friction factor
L = Length
D
=
diameter
V = Velocity
g
=
acceleration due to gravity
• Friction factor = f (pipe roughness Reynolds Number) Re = V D / ν, where ν is the kinematic viscosity • Friction factor not constant for a given pipe
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-10
Moody Diagram
f =?
64 NR
f
hL L V2 D 2g
f=
e/D
DV
Riveted steel Concrete Wood stave Cast iron Galvanized iron Asphalted cast iron Steel or wrought iron Drawn Tubing
e, ft. 0.003 - 0.03 0.001- 0.01 0.0006 - 0.003 0.00085 0.0005 0.0004 0.00015 0.000005
e, mm 0.9 - 9 0.3 - 3 0.18 - 0.9 0.25 0.15 0.12 0.045 0.0015
NR
DV v
Hazen-Williams Equation kL V h = 1.16 D C
1.85
Where: D= diameter (in ft or m) V= velocity (in fps or m/s) C= Hazen-Williams C-factor L = length in feet or meters k = 6.79 for V in m/s, D in m or k = 3.02 for V in fps, D in ft h and L in same length units
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-11
Hazen-Williams C-Factor • C-factor – Measured in field – Backed out in calibration
• Loss of carrying capacity system specific • Typical values – – – –
150 very smooth ideal pipe 130 typical design for new pipe 110 reasonable value for aged pipe 20 highly tuberculated or aged pipes
Hazen-Williams Roughness, C Pipe Material
C
Asbestos Cement Brass Brick sewer Cast-iron New, unlined 10 yr. Old 20 yr. Old 30 yr. Old 40 yr. Old Concrete or concrete lined Steel forms Wooden forms Centrifugally spun Copper Galvanized iron Glass Lead Plastic Steel Coal-tar enamel, lined New unlined Riveted Tin Vitrified clay (good condition) Wood stave (average condition)
140 130-140 100
Copyright © 2008 Bentley Systems Incorporated
130 107-113 89-100 75-90 64-83 140 120 135 130-140 120 140 130-140 140-150 145-150 140-150 110 130 110-140 120
Dec-08
Hydraulics Review
Page 1-12
Manning’s Equation
V = C o R 2 / 3 (h / L )
1/ 2
/n
Co = 1.49 for English units and 1.0 for metric units V = velocity (fps or m/s) R = Hydraulic radius = cross-sectional area/wetted perimeter (feet or meters) h = head loss (feet or meters) L = length (feet or meters) n = Manning’s roughness coefficient (see typical values)
Material Smooth pipe Neat cement AC pipe Ordinary concrete Cast iron
n 0.009 0.010 0.011 0.013 0.015
C-factor vs. n 0.040 0.035
D/V=16s
Manning's n
0.030
D/V=1s 0.025
D/V=0.062s
0.020 0.015 0.010 0.005 0.000
0
20
40
60
80
100
120
140
160
180
C-factor
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-13
Comparison of Friction Equations Darcy-Weisbach
Hazen-Williams
Manning
All Fluids
Water Only
Water Only
Hard to get f
Easy to get C
Easy to get n
Good for all roughness's
Smooth Flow
Rough Flow
Not common in the US
Common in the US
Common in the US (for sewers)
Minor Losses What causes minor losses? fittings
joints
bends
valves
Described by coefficient K in:
h = KV 2 / 2 g Where:
K = minor loss coefficient h = head loss due to minor loss
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-14
Minor Loss K Values
Minor Losses for Valves For valves, a flow coefficient Cv = flow (gpm) that will pass through a valve at a pressure drop of 1 psi Cv can be converted to K, the minor loss coefficient:
888 D 4 k= C v2 Where:
D = diameter (in.) Cv is a function of D, while K is independent of D
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-15
Network Representation • Network represented as of links and nodes • A link has a node at each end LINK NODE
NODE
• Nodes represent junctions, tanks and reservoirs. • Links represent pipes (2 heads) • Pumps and valves are technically links, (2 heads) but are treated as nodes by the user in WaterCAD
Network Formulation 1 QIN Q14
Q12
2 Q25
Q45
4
Q23
5
Q56
3 Q3 6
QOUT
6
• For each node there is a conservation of mass equation: – Node 2:
Q12 = Q25 + Q23
• For each link there is a conservation of energy equation: – Link 2 – 3:
b h2 − h3 = a 23 × Q23
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-16
Numerical Problem • This results in: – M conservation of mass equations – L non-linear conservation of energy equations – M+L equations and M+L unknowns
• Problem - set of n non-linear equations w/n unknowns, must be solved iteratively
Distribution of Flow in Simple Network Method of Balancing Heads
Hardy Cross, University of Illinois Engineering Experiment Station Bulletin 286 (1936)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-17
Timeline of Distribution System Modeling 1930’s
Hardy Cross Network Flow Analysis
1960’s
1970’s
1980’s
Widely Computer available Analysis models for of Networks mainframes and minis
1990’s
Dynamic water quality models
PC-based models ---Steady-state water quality models
2000’s
Future
Integrated modeling Multi-platform - mapping Models database – GIS Critical SCADA Analysis ----Management Contaminant kinetics Integration of Transparent -GIS Optimization Detailed Water Quality Modeling
Steady State Simulation Set up n equations n unknowns
Data entry
Initial solution
No Calculate v, P
Yes
Convergence?
Solve equations for H and Q
Results
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulics Review
Page 1-18
Types of Model Runs
Steady State
Extended Period Simulation
Water Quality
Fire Flow Analysis
Optimization
Flushing
The End Numerical solutions needed to solve pipe networks
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-1
Model Data How do I build a Water Model?
Using Models Overview
Applying the model
Getting started
Water use (consumption, demand)
Network representation (skeletonization)
Pipe properties
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-2
Overview • Model = Software + Data • Model = Approximation of real world • Approximation is no more accurate than the data provided • GIGO: Garbage In = Garbage Out • Most work involves data collection/checking • Always check results to make sure they are reasonable
Steps in Modeling 1. Define scope of modeling 2. Select an appropriate model software 3. Learn how to utilize the software 4. Build the Model Network, Assign Demands and Elevations 5. Skeletonize the model 6. Calibrate the model 7. Define the specific situation to be modeled 8. Input the situation-specific data 9. Run the model 10. Are results reasonable? Make recommendations ….Additional runs required?
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-3
Step 1: Define the Scope
Operations
Engineering
Modeler interacts with… Senior Management
Planning
Do you have these parties identified?
Step 2: Selecting a Software Package • Most software packages work • Selection criteria: – – – – – –
technical features support user interface (look and feel of the software) quality of manuals integration with other software AKA=Interoperability Required effort and time to build the model
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-4
Step 3: Learn how to use the software
Step 4: Building the Model Model Sources • Maps form the basis for representing the system • Use CAD/GIS drawings when available • Use the latest available maps • Verify maps with as-built drawings where needed • Verification with field personnel
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-5
Step 4: Constructing the Network • Convert maps to model • Manual process or automated using CAD / GIS • Assign node/link identifiers (e.g. numbers or labels) – Naming conventions – Automatic labeling – Auto prompting
Diameter Representation
What gets used?
• Nominal diameters vs. Actual diameters • Most important in water quality modeling • Important in small sizes (e.g. sprinklers) OD ID
Diameter 6” DI 50 6” DI 56
ID
OD
6.40”
6.9”
Area-Nm 28.27
in2
Area-ID 32.17
in2
Area-OD 37.39 in2
6.04”
6.9”
-
28.65 in2
32.17 in2
48” DI 50
49.78”
50.8”
1809.56 in2
1946.25 in2
2026.83 in2
48” DI 56
48.94”
50.8”
-
1881.13 in2
2026.83 in2
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-6
Length Representation
3D (side view)
• Actual – not point-to-point • Schematic vs. Scaled
5ft
– Scaled - easier to use – Schematic - easier to build
• 3 Dimensional length
3ft 4ft
– Tools > Options > Project > Use 3D Length
• User defined lengths
Length
Elevation Representation • Used to convert HGL to pressure • What reference point do you use? – Ground? – Pipe? – Customer?
• Be consistent
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-7
Converting HGL to Pressure 564.25’ 50.5 psi 553.84’ 55.0 psi 548.34’ 57.4 psi
545.79’ 58.5 psi
Meter
545.38’ 58.7 psi
HGL = 681.00’ 538.32’ 61.8 psi
Which reference positions would you select?
Obtaining Elevation Data • Topo Maps • Surveying • Digital elevation models (DEM) • Global Positioning Systems (GPS) • Altimeter • Sewer / street maps • As-builts
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-8
Assign Demands
Water Use • Referred to as: – – – –
Usage Consumption Demand Loading
• Demands are assigned to nodes • Unaccounted-for water use?
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Using Models
Page 2-9
Placing Demands at Nodes • If Q(use) New. 3. Select File > Project Properties. 4. Enter Subdivision Workshop as the Title, your name as the Engineer, your company’s name for Company, and select today’s date.
5. Click OK.
2
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
The Workspace and Dockable Windows
The Workspace and Dockable Windows The steps that follow will help guide you through the process of setting up your workspace as well as working with toolbars and manager windows.
Toolbars Toolbar buttons represent WaterCAD/GEMS menu commands. You can remove buttons from any toolbar, and add commands to any toolbar on the Commands tab of the Customize dialog box. Exercise: To add or remove a button from a toolbar 1. Click the Toolbar Options customized).
(down arrow at the end of the toolbar to be
2. Select Add or Remove Buttons to open a menu where you can add or remove the buttons in the toolbar itself.
3. Turn the buttons on or off as needed just by clicking on the menu items.
Managers Most of the features in WaterCAD/GEMS are available through a system of dynamic windows called Managers. When WaterCAD/GEMS first start; the default workspace displays the Element Symbology and Background Layers managers. The Four Possible States for each Manager:
Floating - A floating manager sits above the WaterCAD/GEMS workspace like a dialog box. You can drag a floating manager anywhere and continue to work.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
3
The Workspace and Dockable Windows
Docked Static - A docked static manager attaches to any of the four sides of the WaterCAD/GEMS V8i window. If you click and hold a floating manager, and move it, you will see a docking dialog that looks like Figure 1, as well as individual Figure 1
along all four sides of the docking buttons WaterCAD/GEMS V8i window. When you drag the manager over one of the four sides of the docking dialog it will dock the manager to that side of the window and if you drag the manager to one of the individual docking buttons along the window edges the manager will dock to that side. The manager will stay in that location unless you close it or make it dynamic. A vertical pushpin in the manager's title bar indicates its static state; click the pushpin to change the manager's state to dynamic. When the push pin is pointing downward (vertical push pin), the manager is docked static. Docked Dynamic - A docked dynamic manager also docks to any of the four sides of the WaterCAD/GEMS V8 window, but remains hidden except for a single tab. Show a docked dynamic manager by moving the mouse over the tab, or by clicking the tab. When the manager is showing (not hidden), a horizontal pushpin in its title bar indicates its docked dynamic state. Closed - When a manager is closed, you cannot view it. Close a manager by clicking the in the right corner of the manager's title bar. Open a manager by selecting the manager from the View menu (for example, View > Element Symbology), or by selecting the button for that manager on the appropriate toolbar.
Capabilities of a Docked Static Manager:
To close a docked manager, left-click the in the upper right corner of the title bar. To change a docked manager to a floating manager double-click the title bar, or click and hold the mouse and drag the manager to the desired location. To change a static docked manager to a dynamically docked manager click the push pin in its title bar. To switch between multiple docked managers in the same location left-click that particular manager's tab.
Exercise: To open and dock a manager 1. Select View > Graphs. 2. When the graph manager opens, click and hold the left mouse button as you drag it to the bottom left of the screen and place it under the Background Layers manager. 4
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
The Workspace and Dockable Windows
3. Select Analysis > Scenarios. 4. When the Scenarios manager opens, click and hold the mouse button as you drag it and place it under the drawing pane (the white space where the model will be). 5. Select View > Properties. 6. When the Properties manager opens, click and hold the mouse button as you drag it and place it to the right of the drawing pane. Your workspace should look like the following:
Exercise: To go back to the default workspace 1. Select View > Reset Workspace.
2. Click Yes to reset to the default layout. Note: The next time you start WaterCAD/GEMS, your customizations you have made to the dynamic manager display will not be there any longer. Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
5
Setting up the Network
Setting up the Network The following steps lead you through the setup of the network. Exercise: Creating pipe prototypes 1. Select Analysis > Calculation Options.
2. Double click Base Calculation Options to open the Properties manager. Note: You may dock the Properties dialog if it is more convenient. 3. Set the Friction Method to Hazen-Williams.
4. Close the Calculation Options manager. 5. Select View > Prototypes to set the prototype of all pressure pipes. Note: In this workshop the pipe prototype will be set to 6-inch diameter with PVC for material and a C-factor of 150. 6. Right-click on Pipe and select New.
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Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
7. Double click on Pipe Prototype-1 to open the Properties manager if it is not opened already, and enter 6 in the Diameter (in) field.
8. Click in the Material field, and then click the ellipsis (…) to open the Engineering Libraries manager. 9. Click the + next to Material Libraries, then select the + next to MaterialLibrary.xml and select PVC. 10. Confirm the Hazen-Williams C Coefficient is set at 150.
11. Click Select. Note: The Hazen-Williams C field automatically updates to 150 once PVC has been assigned as the Material. Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
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Setting up the Network
12. Close the Prototypes manager. Exercise: To import a background layer 1. Select the Background Layers manager which is already docked in the workspace or select View > Background Layers. 2. Click the New button and select New File. 3. Browse to C:\Program Files\Bentley\WaterDistribution\Starter. 4. Select Scaled_Network.dxf and click Open. The DXF Properties dialog box opens.
5. Click OK. 6. Click the Zoom Extents
8
button to view the map.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
7. Select File > Save As, enter ScaledNetwork and then click Save. Exercise: Laying out the network 1. Select Tools > Options and click on the Drawing tab. 2. Change the Symbol Size Multiplier to 5 and the Text Height Multiplier to 10.
3. Click OK. Note: On the Element Symbology dialog click the Drawing Style button to choose between CAD or GIS style. If you want CAD style do the above; if you want GIS style leave the Multipliers set to 1.0.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
9
Setting up the Network
4. Follow the next set of instructions to layout the network as shown in the following picture:
Note: To view the text for the pipes and elements, it may be necessary to select the Label check box under Element Symbology for each corresponding element.
5. Start by placing T-1, since P-1 is coming out of the tank. 6. Click the Pipe Layout tool
and move your cursor over to the drawing pane.
7. Right-click and select Tank. Note: You will notice that your cursor has changed from a pressure junction to a tank symbol 8. Left-click once on the drawing to place the tank in the desired position (see previous drawing for tank location). 10
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
9. Move your cursor down slightly, right-click and select Junction. Note: Again, notice how your cursor has changed from a tank to a junction symbol. 10. Left-click once to place J-1 in its correct location and notice how P-1 has automatically been placed for you. 11. Continue laying out the rest of the junctions in the same manner until you reach J-6. 12. After laying out J-6, right click and select Done. 13. Click on J-2 and go across the diagram and click to layout J-7, then up to J-8, right-click and select Done. 14. Connect J-7 to J-4 and right-click to select Done. 15. Click on J-5 and move across and click to create J-9, right-click Done. Exercise: Entering pipe data 1. Click Select
and click on P-1 to open the Properties manager.
2. Enter the following: Has User Defined Length?
True
Length (User Defined) (ft)
450
Exercise: Entering tank data 1. Click on T-1 in the drawing to change the open Properties manager to the tank properties. Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
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Setting up the Network
2. Enter the following: Elevation (Base) (ft)
650
Elevation (Minimum) (ft)
650
Elevation (Initial) (ft)
665
Elevation (Maximum) (ft)
680
Diameter (ft)
50
3. Close the Properties manager. Exercise: Entering junction data 1. Select View > FlexTables. 2. Open the Junction Table under Tables Predefined.
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Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
3. Double click Junction Table to open the FlexTable. 4. Right click on the Label column and select Sort > Sort Ascending.
5. Enter the elevations from the table below for each node: Junction
Elevation (ft)
J-1
620
J-2
605
J-3
580
J-4
545
J-5
510
J-6
580
J-7
580
J-8
600
J-9
490
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
13
Setting up the Network
Your FlexTable should look like the following:
6. Close the Junction FlexTable and the FlexTables manager. Exercise: Using the Demand Control Center 1. Select Tools > Demand Control Center to open the Demand Control Center. The message below will come up on your screen:
2. Read this message and when you are ready, click Yes to continue to the Demand Control Center.
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Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
3. Click the New button and select Initialize Demands for All Elements to add all of the available junctions to the table so you can enter flows and patterns. 4. Right click the Demand (Base)(gpm) column header and select Global Edit. 5. Enter 20 as the Value and then click OK.
6. Click Close on the Demand Control Center dialog. Exercise: Computing the model and reviewing results 1. Select Analysis > Validate or click the Validate has no problems. 2. Select Analysis > Compute or click the Compute
button to verify that the model button.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
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Setting up the Network
3. When the run has completed, the Calculation Summary window opens.
4. To view results, select View > FlexTables and open the Junction Table under Tables-Predefined. 5. Review the Pressure and Hydraulic Grade columns.
6. Open the Pipe Table and review the results.
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Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Setting up the Network
7. Complete the Results Table at the end of the workshop and answer the questions about Run 1. Note: Make sure the units are consistent with those on the answer table. If they are not, modify the units on the reports. Right click the column heading and select Units and Formatting. Make the necessary changes. You also may decrease the Display Precision to round your values to whole numbers. 8. Click OK when completed. 9. You may turn off the background layer to make it easier to find elements and review results. 10. In the Backgrounds Layer manager, uncheck the box for Scaled_Network.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
17
Fire Flow Scenario
Fire Flow Scenario In this section you will walk through the steps to simulate a fire flow at J-6 using the Demand Alternative. Exercise: Creating the fire flow demand alternative 1. Select Analysis > Alternatives. 2. Expand the Demand Alternative to view the Base Demand Alternative.
3. Right click the Base Demand Alternative and select New > Child Alternative. 4. Click the Rename
button to rename the new child alternative Fire Flow at J-6.
5. Open the Fire Flow at J-6 alternative. 6. Turn on J-6 in this alternative by selecting the check box, and change the Demand (Base) (gpm) to 1000.
7. Click Close. 18
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Fire Flow Scenario
Exercise: Creating the fire flow scenario 1. Select Analysis > Scenarios. 2. Right click the Base scenario and select New > Child Scenario. 3. Enter the scenario name as Fire Flow at J-6.
4. Double click Fire Flow at J-6 to open the Properties manager. 5. Select Fire Flow at J-6 as the Demand Alternative.
6. Select Fire Flow at J-6 and select the Make Current
button.
7. Click Compute. 8. Review the results and complete the Results Table at the end of the workshop and answer the questions about Run 2. Note: A network of 6 inch pipes will not work well in this situation. The problem areas are most likely those pipes with the highest velocities and/or friction slopes. Review the pipes with the highest velocities and friction slopes in the pipe table. These pipes will need to be upsized.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
19
Fire Flow Scenario with New Diameters
Fire Flow Scenario with New Diameters In this scenario we are going to try to fix the problem areas from the previous fire flow run by upsizing the pipes with the highest velocities and friction slopes. Exercise: Creating a new physical alternative 1. Select Analysis > Alternatives. 2. Expand Physical to view the Base Physical Alternative.
3. Right-click the Base Physical Alternative and select New > Child Alternative. 4. Click the Rename button to rename the new child alternative New Diameters.
5. Double click New Diameters to open the Physical: New Diameters table. 6. Change the diameters to the following:
20
Pipe
Diameter (in)
P-1
10
P-2
10
P-3
8
P-4
8
P-5
8
P-6
8
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Fire Flow Scenario with New Diameters
6. Click Close. Exercise: Creating the new fire flow scenario for new diameters 1. Select Analysis > Scenarios. 2. Select Base and then click the New button and select Base Scenario. 3. Enter the scenario name as Fire Flow with New Diameters.
4. Double click Fire Flow with New Diameters to open the Properties manager. 5. Select New Diameters as the Physical Alternative and Fire Flow at J-6 as the Demand Alternative.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
21
Bonus
6. Close the Properties manager. 7. Select Fire Flow with New Diameters and click the Make Current button.
8. Click the Compute button. 9. Close the Calculation Summary and review the results. 10. Complete the table at the end of the workshop and answer the first remaining questions about Run 3.
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Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Bonus
Bonus If time permits, try annotating the pipes and junctions to view the results on a plan view and to view how the results change over each scenario. Exercise: To use annotations 1. Select the Element Symbology manager which is already docked in the workspace or select View > Element Symbology. 2. Right-click on Pipe, and select New > Annotation to open the Annotation Properties. 3. On the Annotations Properties manager enter the following: Field Name
Velocity
Initial Y Offset
-20
Initial Height Multiplier
0.7
4. Click OK. 5. In the plan view, you can now see the placement of Velocity for each pipe. Note: This information was determined by the Y Offset that you entered. The placement of text can be changed both horizontally (X Offset) and vertically (Y Offset). 6. Follow the same procedure to annotate Junctions by Pressure. You may vary the X and Y Offsets so the plan view has the look you prefer. 7. When you have annotated the Pipes and Junctions, change the scenario using the Scenario dropdown menu to view the updates to the annotations.
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
23
Results Table
Results Table Run 1
Run 2
Run 3
Pressure at J-1 (psi) Pressure at J-6 (psi) Pressure at J-9 (psi) HGL at J-5 (ft) Velocity in P-1 (ft/s) Velocity in P-6 (ft/s) Flow in P-3 (gpm) Flow in P-7 (gpm) Pipe with highest Headloss Gradient Headloss Gradient in that pipe (ft/1000ft)
24
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. Why is the pressure so high at J-9 even though it is far from the source?
2. Why must you rely so heavily on pipes greater than 6 inch in this fairly small subdivision?
3. What would really happen if you used the system from run 2 and had a fire at J-6 that needed 1000 gpm?
4. How does the split in flow between pipes 3 and 7 change as you change pipe diameters? Why?
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
25
Workshop Review
5. If another source of water were available along the highway at J-9, how might that source affect the design?
6. What else could you do to help the pressures during normal demand periods?
26
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Answers Run 1
Run 2
Run 3
Pressure at J-1 (psi)
19.0
4.9
18.3
Pressure at J-6 (psi)
35.9
-22.0
24.6
Pressure at J-9 (psi)
74.8
33.6
67.7
HGL at J-5 (ft)
662.9
568.0
646.5
Velocity in P-1 (ft/s)
2.0
13.2
4.7
Velocity in P-6 (ft/s)
0.2
11.4
6.4
Flow in P-3 (gpm)
69
567
763
Flow in P-7 (gpm)
71
553
357
Pipe with highest Headloss Gradient
P-1
P-1
P-5
Headloss Gradient in that pipe (ft/1000ft)
2.4
75
15
*Some answers may vary between users due to the nature of this schematic model 1. Why is the pressure so high at J-9 even though it is far from the source? It is located at the lowest elevation in the system.
2. Why must you rely so heavily on pipes greater than 6 inch in this fairly small subdivision? Streets are not laid out with water distribution in mind. More loops would result in smaller pipes/greater reliability.
3. What would really happen if you used the system from run 2 and had a fire at J-6 that needed 1000 gpm? You would not be able to get 1000 gpm. You would have lower flow with higher pressures. Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
4. How does the split in flow between pipes 3 and 7 change as you change pipe diameters? Why? Initially they are the same but there is more flow through 3 as it is increased.
5. If another source of water were available along the highway at J-9, how might that source affect the design? You might need to make P-10 larger so it would not be a bottleneck for the future source.
6. What else could you do to help the pressures during normal demand periods? If possible:
28
Put the tank at a higher elevation (higher static head) Operate the tank with more water in the tank (higher static head). Increase the system looping Add a fire pump to maintain adequate flow/pressure
Building a Network with Fire Flow Copyright © December-2008 Bentley Systems Incorporated
Tanks, Pumps and Valves
Page 3-1
Tanks, Pumps, & Valves
Tanks, Pumps and Valves
TANKS/RESERVOIRS: Store water
PUMPS: Add energy to flow
VALVES: Control the flow of water
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-2
Tanks and Reservoirs • Differences between tanks and reservoirs? • “Tank” and “reservoir” mean different things in different places
Tank • finite volume • water level varies over time in EPS • water level is constant steady-state
Reservoir • infinite volume and constant head (water level) in both steady-state and EPS
Impacts of Tanks and Reservoirs • Provide emergency storage • Equalize pressures during peak flow • Balance water use throughout the day • Potential negative water quality impacts – Long residence times – Poor mixing
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-3
Pumps
• Pump Characteristic Curves – – – –
Head Efficiency Brake horsepower NPSH (req)
• Head (vertical axis) = TDH
H, e, HP, NPSH
• Centrifugal Pumps
Q
• TDH = head added • Model selects operating point along curve
3 Point Pump Curve Pump curve is usually represented as:
hg = h0 − a Qb Where: hg = head imparted by pump h0 = shutoff head (zero flow) Q
= flow
a,b = coefficients describing pump curve
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-4
Defining Pump Curve • Usually 3 points required to define curve • Typical points are: – shutoff head, – most efficient point and – maximum flow
• Best fit curve can also be determined when more than 3 points are specified
Effects of Changing Speed/Impeller Larger impeller or higher speed
Pump Head (feet)
Smaller impeller or lower speed
Discharge (gpm)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-5
Obtaining Head-Discharge Curve • Manufacturer curves • Sources of curves – Catalog – Test – Available even for old pumps
• Older pumps may need pump performance tests • Alternate pump representation
Modeling as Discharge HGL
Head
Future Pumps
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-6
Head
Modeling Pump as Known Power
Pump Curve
h=k HP/Q HP=water power added (not motor HP)
Flow
Variable Speed Pumps • Pump with variable speed drive • Current technology is VFDs • Reshape electrical input • Relative speed = Speed/Max Speed • WaterGEMS calculates relative speed • Can be controlled by discharge or suction side of pump
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-7
Variable Speed Pumps • May be worthwhile – Dead end systems – Widely varying system head curves
• Speed adjusted with pump affinity laws:
Q = const 3 ND
H = const 2 2 N D
• Must consider TOTAL Life-cycle costs: HVAC, capital, maintenance, footprint
System Head Curve • Head needed to move a given flow thru pump • Not single curve but a band of curves – Tank water levels – System demand
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-8
System Head Curve (Simple Case)
HGL
Discharge Tank
Head Loss Lift Suction Tank
Pump
Flow
System Head Curve (Real System)
Discharge Tank
HGL
Suction Tank
Pump
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-9
Creating System Head Curve
HGL
Discharge Tank
120’150’
Distribution Grid
Suction Tank Pump 200 -200 Pump Suction 400 -400 Discharge
Automated System Head Curves • Specify pump • Range and interval of graph • Scenario (s)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-10
Pump Operating Point
Pump Operating Point
Discharge (gpm)
Pump Selection • Determine design flow • Develop system head curve(s) • Check agreement of: – Design flow – Operating point (s) – Best efficiency point
Modeling
• Check pump combinations • Verify operation in model • Examine life-cycle costs (energy cost)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-11
100 1
10
h, ft
1000
Pump Coverage Chart for Selection
10
100
1000
10,000
100,000
Q, gpm
Modeling Valves and Things • Isolating valves • Control valves – composite node – link with inlet and outlet nodes
• Check valve – property of pipe – comes with pump
• Flow emitter – property of node • Altitude Valve – comes with tank • Backflow preventer – general purpose valve • Water meters – minor loss on pipe – general purpose valve – flow totalizer function
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-12
WaterCAD Valves Pressure Reducing Valve (PRV): • limit outlet pressure to preset value
Pressure Sustaining Valve (PSV): • Maintain minimum inlet pressure
Pressure Breaker Valve (PBV): • force a specified pressure loss across the valve
Flow Control Valve (FCV): • limit the flow through valve to specified amount
Throttle Control Valve (TCV): • simulate a partially closed valve (EPS)
Generalized valve (GPV): • any loss vs. flow curve
PRV States Active
Inactive
Controlled by model Controlling – limiting pressure
no head loss
Closed manual
no flow
Open state – minor loss only Closed state – no flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-13
Active Pressure Reducing Valve Setting = 55 Demand = 300 gpm
55
70
Q = 300
Control 70
65
55
Q=0
Closed 40
55 Q = 300 gpm
Open
Active Pressure Sustaining Valves
55
55
55
Demand = 300 gpm 250 gpm
Controlling
70 Open
55
45
55
69
300 gpm
0 gpm
Closed
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-14
Reduced Pressure Backflow Valve or (Pipe w/minor losses)
Pressure drop in psi
Flow in gpm
General Purpose Valve (GPV) • Individual Element • Enter table of Q vs. Head Loss • Table usually given in pressure drop vs. flow • Specify elevation and initial status
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-15
Water Meters • Minor loss on pipe • Usually pressure drop vs. flow given • K = 888 PD4/Q2 • Typical Ks – Pos. Displ./Turbine – 4-14 – Compound – 10-35 – Fire service – 4-5
Flow Totalizer • Represents metering behavior of meter • Report provided for any element • Gives demands for junction elements • Gives inflow for tank/reservoir elements • Gives flow for link (pipe, valve, pump) elements • Specify begin and end of meter period
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Tanks, Pumps and Valves
Page 3-16
Flow Emitter • Property of junction node • Used to represent sprinklers, orifices, pressure dependent demands • Emitter flow added to demands • Specify emitter coefficient, gpm at 1 psi
Q = k (P )0.5
The End In theory, there is no difference between theory and practice. But in practice, there is.
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Building a Network with Pumps, Tanks and PRVs Workshop Overview Given the water distribution system shown below, you will construct a model and perform two runs. You will need to enter the data for the system using a roughness coefficient of 100 for the pipes, which are all 10-year-old cast iron.
Workshop Prerequisites
A fundamental understanding of Water Distribution Systems is recommended
Workshop Objectives After completing this workshop, you will be able to:
Set up element prototypes
Enter pump definitions and pump data
Model PRVs and Tanks in a network
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
1
Creating a New Project and Prototypes
Creating a New Project and Prototypes In this section you will run through creating a new WaterGEMS project and setting up prototypes for your new project. Exercise: Creating a new WaterGEMS project 1. Open WaterCAD V8i or WaterGEMS V8i. 2. Click Create New Project on the Welcome dialog or select File > New to create a new project.
Prototypes Before we get started laying out the system, we will set up a prototype for all the pipes to be 8-inch diameter, 10-year-old cast iron pipe with a user-defined length of 1500 ft. Exercise: Setting the pipe prototype specifications 1. Select View > Prototypes to open the Prototype manager.
2. Left click once on Pipe within the Prototype manager and then click on the New button. Note: This will create a new prototype called Pipe Prototype-1.
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Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Creating a New Project and Prototypes
3. Double click on Pipe Prototype-1 to open this prototype and set the Diameter (in) as 8 inches. 4. Next to the Material field, click on the ellipsis (…) button to open the Engineering Libraries.
5. Expand Material Libraries and MaterialLibrary.xml to find the material Cast Iron. 6. Left click once on Cast Iron to display this material’s properties on the right side of the manager.
7. Click Select. You should now have Cast Iron as the chosen Material on the Prototype manager. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
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Creating a New Project and Prototypes
Note: The default roughness value for cast iron pipe is 130, since it is assumed to be new pipe in the material library. 8. Change the Hazen-Williams C to 100 by simply typing it in the field. 9. Change Has User Defined Length? from False to True using the dropdown menu. 10. Enter in 1500 in the Length (User Defined) (ft) field. Your Pipe Prototype should now look like the one below:
11. Close out of the Pipe Prototype and Prototype managers by clicking the small close button. 12. Select File > Save As, name the file PumpsAndTanks and click Save.
4
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
System Layout
System Layout Exercise: Laying out the system 1. Now you will layout the system as shown below:
2. To begin, select the Layout tool
from the tool palette.
3. Move your cursor over to your drawing pane, right-click and choose Reservoir. 4. Place the reservoir on the left hand side of the drawing window as shown above. 5. After you place the reservoir, move your cursor over, right-click and choose Junction. 6. Place junction, J-1 and then right-click to select Pump. 7. Place the pump on your drawing and then change the element type to a Junction and continue laying out J-2 and J-3. 8. After J-3, right click and select PRV then place the PRV as shown. 9. Next, right click, pick Junction and layout junctions J-4 and J-5 and continue laying out the rest of the system. Note: Make sure to lay out the network in sequential order so that the numbering of the network corresponds to that shown above. 10. The PRVs need to be drawn from the upstream node to the downstream node to indicate the direction of flow. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
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System Layout
Hint: If you lay out a pump, valve, or pipe in the direction opposite the one you want, you can change its direction by clicking once on the element in the drawing window and then right clicking and choosing Reverse. 11. Before continuing, review each PRV and make sure that they are oriented correctly (from upstream to downstream) and if they are not, use the Reverse option to orient them correctly.
6
Node
Downstream Pipe
PRV-1
P-6
PRV-2
P-8
PRV-3
P-16
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Entering Element Data
Entering Element Data Enter the data for the pipes and junction nodes as provided in the following tables. The best way to do this is using the FlexTables. Note: Make sure your FlexTables are sorted so they match the order of the elements in the following tables before entering the data. Right click the Label column and pick Sort > Ascending. Exercise: Entering pipe data 1. Select View > Flex Tables. 2. Open the Pipe Table from the Tables – Predefined section, and enter the following: Pipe No.
Diameter (in.)
Length (ft)
P-1
12
10
P-2
12
10
P-3
12
5000
P-4
8
1000
P-5
8
100
P-6
8
1500
P-7
8
1500
P-8
8
1500
P-9
8
100
P-10
8
1000
P-11
8
1500
P-12
8
100
P-13
8
1000
P-14
8
1800
P-15
10
1500
P-16
10
1000
P-17
12
1500
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
7
Entering Element Data
4. While you are in the Pipe FlexTable, right click on the heading for the Length (User Defined) (ft) and pick Units and Formatting. 5. Change the Display Precision to 0.
6. Click OK.
Note: Notice that now the lengths are displayed as 1,500 instead of 1,500.00. Notice also that many of the fields in the tables have values of (N/A). This is because the values have not yet been calculated. 7. Close the Pipe FlexTable and save the file. 8
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Entering Element Data
Exercise: Entering junction data 1. Select View > FlexTables. 2. Open the Junction Table under Tables – Predefined. 3. Enter in the Elevation and Demand data given below: Node
Elevation (ft)
Demand (gpm)
Node
Elevation (ft)
Demand (gpm)
J-1
820
0
J-6
890
75
J-2
820
50
J-7
890
80
J-3
870
50
J-8
910
0
J-4
770
75
J-9
905
50
J-5
770
50
The Junction FlexTable with the elevation data should look like the following:
Note: To enter in the Demand data, you could enter in the data within the FlexTable by clicking the ellipsis button (…) within each cell in the Demand Collection column. This will open a table that will allow you to enter in the demand associated with that single node. 4. Alternatively, you can close out of the FlexTables and go to the Demand Control Center under Tools > Demand Control Center, which is often the quicker method of entering in demand data. 5. Click Yes when you are prompted with the dialog shown on the next page. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
9
Entering Element Data
6. Once inside the Demand Control Center, select the New button and choose Initialize Demands for All Elements. 7. Fill in the Demand (Base) column from the data in the table on the previous page.
8. Click Close when done. Exercise: Entering PRV Data 1. Open the PRV Table from the FlexTables manager. 2. Enter the following:
10
PRV Label
Elevation (ft)
Diameter (in)
Hydraulic Grade Setting (initial) (ft)
PRV-1
820
4
935
PRV-2
830
4
940
PRV-3
830
4
940
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Entering Element Data
3. Check the PRV FlexTable to see if Hydraulic Grade Setting (Initial) is in the table. If it is, then fill in that column and go to Step 8. 4. If it is not, you will need to add the column for Hydraulic Grade Setting (Initial) to the PRV FlexTable. 5. Within the PRV FlexTable, select the Edit
button.
6. Scroll through the Available Columns list, highlight Hydraulic Grade Setting (Initial), and select the first Add button. 7. Using the Up arrow under Selected Columns (at the bottom), move Hydraulic Grade Setting (Initial) under Diameter.
8. Select OK to update the table with the values from the PRV table on the previous page. Note: Make sure Label is sorted in ascending order and enter the data from the table.
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Entering Element Data
9. Close out of the PRV FlexTable and FlexTable manager to return to the main drawing screen. Exercise: Entering reservoir data 1. Open the Properties manager for the Reservoir by clicking once on R-1 if your Properties manager is docked; if it is not currently docked, simply double click on R-1 and this will bring up the Properties manager. 2. Enter in an Elevation (ft) of 950 for R-1.
Exercise: Creating a pump definition and entering pump data 1. To enter in the Pump data, open the Pump Definition manager by selecting Components > Pump Definitions. 2. Click the New button. 3. Accept the default name and enter the values from the table below for a Standard (3 Point) pump. Flow (gpm)
Head (ft)
Shutoff:
0
160
Design:
1000
130
Max. Operating:
1400
111
4. After you have entered the data, view the graph. Note: Do not worry about the blue line. That is only used for efficiency in energy costing which we are not doing here.
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Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Entering Element Data
5. Click Close and save your file. 6. Back in the main drawing screen, click on the PMP-1 to open the pump’s Properties manager. 7. Enter in the Elevation (ft) of the pump as 945. 8. Use the dropdown menu next to the Pump Definition field and choose the pump you just created.
Exercise: Entering tank data 1. Click on T-1 to open the Properties manager. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
13
Entering Element Data
2. Enter in the data given below:
14
Elevation (Base) (ft)
Elevation (Minimum) (ft)
Elevation (Initial) (ft)
Elevation (Maximum) (ft)
Elevation (ft)
Diameter (ft)
1010
1030
1050
1070
950
50
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Run 1 – AVG Daily
Run 1 – AVG Daily In this section you will run the model as is for an average daily run. Exercise: Computing the model 1. Select Analysis > Scenarios. 2. Set up a scenario incorporating the Base-Demand Alternative to run a steady state analysis. Note: The default Scenario, named Base, should be the appropriate setup.
3. Rename the Base Scenario to AVG Daily by right-clicking the Base Scenario, selecting Rename, and typing the new name.
4. Click the Compute
button within the Scenarios manager.
5. Review the results and answer the questions for Run 1. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
15
Run-2 – AVG Daily plus Industry
Run-2 – AVG Daily plus Industry Now, suppose that an industry wants to move into a site near junction node J-5 and you have been asked to evaluate the adequacy of the distribution system. The new industry demand at this node is 1500 gpm, and it is fairly steady over the day. The difference between this run and Run 1 is the increased demand. You are going to set up a new demand alternative to create a scenario for this run. Exercise: Creating the AVG Daily + Industry Base Demand Alternative 1. Select Analysis > Alternatives and highlight the Base Demand Alternative. 2. Right-click and choose New > Child Alternative. 3. Rename this new alternative AVG Daily + Industry. 4. Open the new alternative by double clicking on it. 5. Change the demand of J-5 from 50 to 1500 gpm to simulate the industry’s requirements.
Note: Notice how there is now a check mark next to J-5 indicating that its data has changed from that of the parent alternative. 6. Click Close and exit the Alternatives windows. Exercise: Creating the AVG Daily + New Industry Scenario 1. Create a new child scenario to incorporate this Demand Alternative. 2. Select Analysis > Scenarios. 3. Right click on the AVG Daily scenario and select New > Child Scenario. 4. Name the new Scenario AVG Daily + New Industry. 16
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Run-2 – AVG Daily plus Industry
5. Open the new scenario and change the Demand Alternative to Avg Daily + Industry.
6. Within the Scenarios manager, click the down arrow next to the Compute button and choose Batch Run.
7. Check both Scenarios and click Batch.
8. Review the results and answer the questions for Run 2. Note: Remember to switch the current scenario to the AVG Daily + New Industry scenario before you start answering Run 2 questions. Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions – Run 1 – AVG Daily 1. What is the hydraulic grade line elevation at junction J-6? At J-4?
2. Which PRVs will be the main feed to the lower zone? As the pressure drops, which PRV will open last: PRV-1, PRV-2, or PRV-3? Why?
3. Is tank T-1 filling or draining?
4. Are there any hydraulic problems in the system?
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Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
5. What can you say about the capacity of the system if this output is for average flow conditions?
6. If the pump is a nominal 1000 gpm pump, what can you generally say about its efficiency?
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Workshop Review
Questions – Run 2 - Industry Demand of 1500 gpm 1. What is the hydraulic grade line elevation at junction J-6? At J-4?
2. Is the pressure adequate in the lower zone?
3. Is tank T-1 filling or draining?
4. Are there any hydraulic problems in the system?
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Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
5. What can you say about the capacity of the system if this output is for average flow conditions?
6. If the pump is a nominal 1000 gpm pump, what can you generally say about its efficiency?
7. How much more would the pump PMP-1 need to produce to keep the tank T-1 from draining?
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Workshop Review
Answers – Run 1 1. What is the hydraulic grade line elevation at junction J-6? At J-4? J-6 has HGL at 1052 ft J-4 has HGL at 940 ft
2. Which PRVs will be the main feed to the lower zone? As the pressure drops, which PRV will open last: PRV-1, PRV-2, or PRV-3? Why? PRV-1 will open last because it has a lower HGL setting.
3. Is tank T-1 filling or draining? Filling
4. Are there any hydraulic problems in the system? No
5. What can you say about the capacity of the system if this output is for average flow conditions? The system is adequate to meet capacity for average daily conditions.
6. If the pump is a nominal 1000 gpm pump, what can you generally say about its efficiency? Good efficiency, because it is operating close (within 60 gpm) to the design point on the pump curve. A more accurate efficiency % can be determined by consulting the efficiency curves in the pump manufacture’s catalog.
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Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Answers – Run 2 1. What is the hydraulic grade line elevation at junction J-6? At J-4? J-6 has HGL at 1003 ft J-4 has HGL at 935 ft
2. Is the pressure adequate in the lower zone? Yes.
3. Is tank T-1 filling or draining? Draining
4. Are there any hydraulic problems in the system? Yes. The pump cannot keep up with demands.
5. What can you say about the capacity of the system if this output is for average flow conditions? The system is not adequate to meet capacity for average daily conditions because the tank is draining.
6. If the pump is a nominal 1000 gpm pump, what can you generally say about its efficiency? The pump does not appear to be operating efficiently. It is operating at approximately 150 gpm above its design operation point. A more accurate efficiency % can be determined by consulting the efficiency curves in the pump manufacture’s catalog.
7. How much more would the pump PMP-1 need to produce to keep the tank T-1 from draining? Approximately 730 gpm
Building a Network with Pumps, Tanks and PRVs Copyright © December-2008 Bentley Systems Incorporated
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Calibration
Page 4-1
Model Calibration Calibrating Steady-State models
What is Calibration?
Comparing observed values to modeled values
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Adjusting model variables to match observed values
Dec-08
Calibration
Page 4-2
Calibration Methods • Manual Calibration – Time consuming – Precise yet manual changes to model – Good for sensitivity analysis
• Darwin ® Calibrator – – – – –
Enter field data set(s) Change model variables rapidly Darwin makes the adjustments Uses genetic Algorithims Included in WaterGEMS, addition in WaterCAD
Why Calibrate? Knowledge of the system = Certainty = Savings • Accurate models = good decisions • Build confidence in model results • Decisions involve millions • Gain insight into system operations • Find energy hog’s, improve efficiency
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Dec-08
Calibration
Page 4-3
Calibration Process • Objective: Find the best adjustments fulfilling the restrictions • Like an older model TV: …showing a fuzzy picture of observed vs. predicted values, through trial and error you adjust the many knobs… the end goal is to find the best adjustment(s)
Types of Calibration
Static Methods (Used with steady-state model) • Hydrant (fire flow) test • C-Factor test
Copyright © 2008 Bentley Systems Incorporated
Dynamic Methods (Used with EPS model) • Comparison to tank level, pressure and flow traces • Use tracer tests
Dec-08
Calibration
Page 4-4
Data Collection • Accuracy
H = z + 2.31 p (US)
• Accuracy in Measurement – Pressure, Elevation Gradient: ±1 – 3 ft / (±0.5 – 1 m) – Flow – 5% accuracy – Tank levels – ±1 ft (±50 cm) • SCADA data • Chart recorders/data loggers • Calibrate gages and meters
Where to Collect Data? • Away from – Tanks – Pumps – PRVs
• Near model nodes
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Dec-08
Calibration
Page 4-5
When and How to Collect Data? • To evaluate strategically important points of measurement and data collection • Periods of high demand • Not to disrupt service/operation • Collect operational parameters • Report any irregular flows • Record boundary head – Tank levels – PRV status – Pumps status/speed
Head Loss Needed Tank
Actual Normal HGL
Negligible difference
Model Normal HGL Actual High Flow HGL Model High Flow HGL Detectable Difference
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Calibration
Page 4-6
Comparisons
HGL
Pressure
• Compare HGLs not pressure
Location
Location
Comparison to Pressure Drop • Match pressure drop during hydrant flow test, not HGL value • OK for C’s when normal HGL is flat • Why doesn’t normal HGL match? • Model is wrong at high and low demand • Need to find and eliminate errors
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Dec-08
Calibration
Page 4-7
Setup for Hydrant Flow Test Residual Hydrant
Ps
Flowed Hydrant
Pt
Qt
1. Measure static pressure 2. Open flow hydrant 3. Measure test pressure at residual hydrant • Goal: at least 10 psi drop between static and residual readings • Collect information on state of system during the test (pumps, tanks, valves, demands).
Improved Fireflow Test Method • Use of digital pressure gages on multiple hydrants • Flow multiple hydrants in sequence • 3-person crew 1 hour to perform test – Includes setup, test & breakdown
• Capital costs: $3000 - $5000 +/– 2 pitot gages, 6 digital pressure gages, 1 analog gage
• Results in much larger data base • See Opflow April 2006 – “Calibrating Distribution System Models with Fire-Flow Tests” – Grayman et al.
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Dec-08
Calibration
Page 4-8
Flow and Pressure Hydrants
Flow Hydrant
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Dec-08
Calibration
Page 4-9
Digital Pressure Gage
Digital and Analog Pressure Gages
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Dec-08
Calibration
Page 4-10
Pressure Measurements
Test Results
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Dec-08
Calibration
Page 4-11
C-Factor Test • Indirect “measurement” of C-factors in the field • Estimation of C-factor based on application of Hazen-Williams equation with measured head loss, flow, diameter, length • Calculate, C = 8.71 V D-0.63 (h/L)-0.54 – V (fps), D (inches), hL (feet), & L (feet)
H1
(H1-H2 = hL)
H2 Flow (Q) V=Q/A
Length(L), diameter(D)
Roughness Test Procedures • Method 1: Measure pressures at point 1 and 2 (hydrant), induce flow and measure flow in pipe at hydrant or using a magnetic meter or probe in pipe – Select a section of pipe with constant diameter and material and few minor losses – Close valves so that flow in test section is constant – Have accurate information on difference in elevation – Have or induce a reasonably high flow rate
1
Induced flow
2 X X
X X
Copyright © 2008 Bentley Systems Incorporated
X X
X X = closed valve
Dec-08
Calibration
Page 4-12
Roughness Test Procedures • Method 2: run hose from point 1 to point 2 with a manometer (parallel hose). Directly measures headloss – Select a section of pipe with constant diameter and material and few minor losses – Connect hose from point 1 to point 2 – Close valves so that flow in test section is constant – Have accurate information on difference in elevation – Have or induce a reasonably high flow rate HL1 = HL2
1
Induced flow
2 X
X
X
X
X
X
X X = closed valve
Hydrant Flow Measurement
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Dec-08
Calibration
Page 4-13
Hydrant Flow Measurement
Pressure Gage on Hydrant
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Dec-08
Calibration
Page 4-14
What Parameters to Adjust? • Primary parameters to Adjust – C-factor/Roughness – Demands – Valve states
• Identify source of error – If errors present at Average flow/demand, verify: • Elevations • Boundary heads • Valve state
– If errors present at High flow/demand, verify • Closed valves • C-factor/roughness • Demands
Understanding the Adjustments… Using our common sense is part of engineering • Are the adjustments reasonable? • Were there special circumstances – Were there any unusual demands? – Were then any closed valves found? – What time of day was it?
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Dec-08
Calibration
Page 4-15
What is Good Enough? • Calibration is an ongoing process - Never done • Calibration requirements depend on the use of the model (e.g. fire flow, energy consumption • Dependability of the model will improve with additional calibration • Calibration is hard work, • Takes time and costs $ • Initial calibration – validate before later uses
Good Enough Yet? • No hard and fast calibration standards • AWWA ECAC Committee draft guidelines • Use sensitivity analysis • Model should support the decision-making process • Stop when cost for additional calibration exceed benefits of additional calibration
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Dec-08
Calibration
Page 4-16
Calibration Tips • Perform field data tests to confirm model • May need to repeat tests if system changes • Avoid calibration by compensating error • Record boundary conditions at time of test • Use calibrated equipment • Know the elevations of the pressure gauges • Do not neglect leakage, especially in older systems • Keep good records
The End Good calibration leads to good decisions
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Steady State Calibration of Field Measurements Workshop Overview You have a network model, which you have built using the best available data. You also have three sets of field data that were collected during average day water use and during two separate hydrant flow tests. The field data consists of flows measured at the hydrants and pressures measured at other locations in the system. The pressures were converted to hydraulic grade lines for use during the calibration process. You must calibrate the model and reproduce the results of the field measurements.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
Workshop Objectives After completing this workshop, you will be able to:
Manually calibrate a network based upon field measurements
Use the Demand Control Center to adjust demands
Manually adjust pipe C-factors
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Reviewing Field Data
Reviewing Field Data In this section you will review the field data shown below in the WaterCAD/GEMS interface. You have been given three kinds of pressure (and HGL) data to use for the calibration:
Pressures collected at a number of nodes during static conditions Pressures at residual hydrants during flow tests Pressure transmitters at the pump discharge (J-1) and a monitoring point (J13)
You know that one pump is operating at the pump station, and both tanks have a water surface elevation of 160 ft. There are no unusual events in the system to cause abnormal demands. You have taken your elevation data from maps with 0.6 m contour intervals, so you feel confident about elevations. You checked the pump curve and know it is correct. There are two kinds of pipes in your system:
Older cast iron pipes from the original system, which will initially have a Cfactor of 90. Newer ductile iron pipes, which will initially have a C-factor of 130.
Note: These C-factors have already been assigned. The hydrant flow test at J-10 produced 1125 gpm and the test at J-31 produced 1050 gpm. These flows will be entered as demands in the appropriate demand alternatives. The data collected in the field is as follows: Static Condition
2
Location
Pressure (psi)
Corresponding HGL (ft)
J-1
70
186
J-2
57
156
J-4
47
159
J-8
30
159
J-12
53
157
J-13
51
157
J-23
43
158
J-32
57
157
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Reviewing Field Data
Fire Flow at J-10 (1125 gpm) Location
Pressure (psi)
Corresponding HGL (ft)
J-1
65
176
J-10
27
129
J-13
41
135
Fire Flow at J-31 (1050 gpm) Location
Pressure (psi)
Corresponding HGL (ft)
J-1
65
175
J-13
37
126
J-31
34
108
This data has already been set-up as User Data Alternatives making it easy to compare the calculated results with measured field data. Hydraulic grade lines have also been entered. Exercise: Reviewing existing data in WaterGEMS The network model to be used in this workshop is in a file called SteadyCalibration.wtg. 1. Start WaterCAD V8i or WaterGEMS V8i. 2. Open the SteadyCalibration.wtg file in the following location: C:\Program Files\Bentley\WaterDistribution\Starter. 3. Open the Alternatives manager and go to the User Data Extensions Alternative and review the field data. 4. Double click on the User Data Extension category or click on the plus sign next to the category to see the User Data Alternatives.
5. Each User Data Alternative has been named according to the field data it holds. Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Reviewing Field Data
6. Double click on each User Data Alternative to open it. Note: The default display will be pipe information, but our field data (HGLs) are Junction information. 7. Click on the Junction tab to view the data.
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Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Creating Baseline Scenarios
Creating Baseline Scenarios In this section you will create the alternatives and scenarios for your baseline data. Exercise: Creating demand alternatives for the collected data 1. The first step is to set up demand alternatives that correspond to Average Day, Average Day + Hydrant Flow at J-10, and Average Day + Hydrant Flow at J-31. Note: Average Day demands already have been entered under the Base Demand Alternative. 2. You want to retain the Base Demand Alternative because it will be needed later in the workshop, so create a child alternative from it called Average Day. 3. Create two child alternatives from Average Day called Hydrant Flow at J-10 and Hydrant Flow at J-31. Your screen should appear as follows:
4. Edit the Hydrant Flow at J-10 alternative, locate J-10 in the node list, select it, and input the hydrant flow rate of 1125 gpm.
5. Click Close to apply the demands.
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
5
Creating Baseline Scenarios
6. Edit the Hydrant Flow at J-31 alternative, locate J-31 in the node list and select it, and input the hydrant flow rate of 1050 gpm.
7. Click Close to apply the demands and save your file. Exercise: Creating new scenarios for the new alternatives 1. Start your calibration by setting up three Scenarios using the 3 different Demand Alternatives and the 3 different User Data Alternatives.
2. Make sure the correct Demand and User Data alternatives are listed with each Scenario. Scenario
Demand Alternative
User Data Alternative
Average Day
Average Day
Static Condition
Average + Flow at J-10
Hydrant Flow at J-10
Fire Flow at J-10
Average + Flow at J-31
Hydrant Flow at J-31
Fire Flow at J-31
3. After the three Scenarios are prepared, use the pull down symbol next to the Compute button, and select Batch Run.
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Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Creating Baseline Scenarios
4. Click on all three boxes and then click on the Batch button to run all three Scenarios. Exercise: Using FlexTables to view results 1. Use the FlexTables to view the output and fill in the first column of the results table. Note: Remember the field data is already entered into the model as User Data, but this column of information may not be in the pre-defined Junction Table. 2. With the Junction Table open, you can add the User Data column by clicking on the Edit icon. 3. Find and highlight Observed HGL in the Available Columns. 4. Click the single Add button to add it to the Selected Columns and then click OK.
You will now see an Observed HGL column in the Junction Table. Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Creating Baseline Scenarios
Note: You had limited field data so several of the junctions will have no Observed HGL. Focus on the junctions that you do have Observed HGL data for (Sorting the data first, then filtering the data can make this easier) and fill in the calculated values in the Results Tables at the end of the workshop. Remember to note which scenario is active when viewing the Junction Table. You also can select different scenarios while the table is displayed.
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Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Adjusting Demands
Adjusting Demands For the next three runs, we will increase demands by a factor of 2 at each junction, except for the hydrant flow rates. You will set up three additional Demand Alternatives and Scenarios. User Data are field measurements, so the User Data alternatives already prepared will be used again. Exercise: Varying demands with alternatives 1. Open the Alternatives manager, and generate another child from the Base Demand Alternative. 2. Call the new child demand alternative 2X Average Day. 3. Now create 2 child alternatives from 2X Average Day called 2X Average Day + J10 and 2X Average Day + J-31.
4. Edit 2X Average + J-10 and input 1125 gpm at junction J-10.
5. Edit 2X Average Day + J-31 and input 1050 gpm at junction J-31. Exercise: Creating the new 2x scenarios 1. Create three more scenarios. 2. Assign descriptive names to the scenarios. Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Adjusting Demands
3. Assign the new Demand Alternatives and the appropriate User Data Alternatives to these new Scenarios.
Note: You are not ready yet to run these new scenarios. You need to double the demands in 2X Average Day before you make your runs. Exercise: Applying double demands 1. Set the Scenario 2X Average Day as active and open the Demand Control Center by choosing Tools > Demand Control Center.
2. Right click on the heading of the Demand column and select Global Edit. 3. Change the Operation to Multiply by 2, and then click on OK. 10
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Adjusting Demands
Note: All of the original average daily demands have doubled. In addition, since 2X Average Day is the parent to 2X Average Day + J-10 and 2X Average Day + J-31, all of the demands in those alternatives also doubled, except the hydrant flow rates at J-10 and J-31 which were input as local data.
4. Close the Demand Control Center and use FlexTables to confirm this is accurate.
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Adjusting Demands
Exercise: Batch Run of the new scenarios 1. Open the Scenarios manager, and batch run the 3 new scenarios with doubled average demands and hydrant flows.
2. Close the Scenarios manager, and use FlexTables to compare these results with the field data. 3. Fill in the Results Tables at the end of this workshop.
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Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Adjusting C-Factors
Adjusting C-Factors For the next three runs, we will go back to using average daily demands, and will try reducing C-factors to 80% of their original values. Pipe C-factors are a physical property, so you need to create a new Physical Alternative. Exercise: Adjusting the C-Factors 1. Open the Alternatives manager and expand the Physical Alternative. 2. Create a child alternative from Base-Physical. 3. Call the child 80% C-Factors.
4. Edit 80% C-Factors and right click on the column heading for Hazen-Williams C. 5. Globally Multiply all pipe C-factors by 0.8.
6. Create three more Scenarios pairing the Average Day, Hydrant Flow at J-10, and Hydrant Flow at J-31 Demand Alternatives with the new Physical Alternative 80% C-Factors. Note: Make sure that the correct Demand, Physical, and User Data Alternatives are listed correctly for each Scenario. Scenario
Physical Alternative
Demand Alternative
User Data Alternative
Average with 80% C
80% C-Factors
Average Day
Static Condition
Average, 80% C, Flow at J-10
80% C-Factors
Hydrant Flow at J-10
Fire Flow at J-10
Average, 80% C, Flow at J-31
80% C-Factors
Hydrant Flow at J-31
Fire Flow at J-31
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
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Adjusting C-Factors
7. Batch run these three Scenarios, and fill in the third column in the Results Table.
Exercise: Additional Runs (If time allows) 1. Given the feel you now have for the model, try making two additional runs to zero in on the field measurements. Note: Do not focus too much on static conditions, but rather on the fire flow tests. Hint: Given the pressure drop near the pump, you might look for a closed or partially closed valve on one of these pipes. Valves may be indicated by closed pipes.
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Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Results Tables
Results Tables Static Condition Location
HGL Observed (ft)
J-1
186
J-2
156
J-4
159
J-8
159
J-12
157
J-13
157
J-23
158
J-32
157
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
HGL User 1 (ft)
HGL User 2 (ft)
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
HGL User 1 (ft)
HGL User 2 (ft)
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
HGL User 1 (ft)
HGL User 2 (ft)
Fire Flow at J-10 Location
HGL Observed (ft)
J-1
176
J-10
129
J-13
135
Fire Flow at J-31 Location
HGL Observed (ft)
J-1
175
J-13
126
J-31
108
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
15
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. Did adjusting the nodal demands make a difference in the HGL? Why?
2. After which node did you notice a fairly abrupt drop in HGL in the observed data?
3. Did changing the C-factors have a bigger effect on the static or fire flow runs?
4. What did you end up adjusting and why?
5. If you could get more data, what data would you get?
16
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
This page left intentionally blank.
Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers Static Condition Location
HGL Observed (ft)
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
J-1
186
166
161
168
J-2
156
162
156
162
J-4
159
160
159
160
J-8
159
160
159
161
J-12
157
163
159
164
J-13
157
162
158
163
J-23
158
161
158
161
J-32
157
162
158
163
Location
HGL Observed (ft)
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
J-1
176
155
142
154
J-10
129
146
134
139
J-13
135
150
136
146
Location
HGL Observed (ft)
HGL Run 1 (ft)
HGL Q=2x (ft)
HGL C=80% (ft)
J-1
175
151
137
147
J-13
126
141
125
132
J-31
108
124
105
107
Fire Flow at J-10
Fire Flow at J-31
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
17
Workshop Review
1. Did adjusting the nodal demands make a difference in the HGL? Why? It had little effect on the static condition run. It made a significant change on the fire flow runs. The Extra flow caused extra head loss but in the static condition scenario the velocity was so low the HGL was flat.
2. After which node did you notice a fairly abrupt drop in HGL in the observed data? J-1 Closed valve suspected downstream of that valve.
3. Did changing the C-factors have a bigger effect on the static or fire flow runs? It had a bigger effect on the fire flow runs. The velocity was too low in static run.
4. What did you end up adjusting and why? Closed pipe P-22. Lowered C factors for cast iron to 60% Changed demands as shown in the table on the next page
5. If you could get more data, what data would you get? Another fire flow test with several residual gages downstream of P-22.
18
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Adjusted Demands (gpm) Node
Initial Demand (gpm)
Adjusted Demand (gpm)
Node
Initial Demand (gpm)
Adjusted Demand (gpm)
1
100
120
18
0
20
2
80
100
19
0
15
3
55
55
20
0
12
4
100
120
21
0
20
8
0
10
22
10
25
9
15
23
23
5
15
10
8
9
24
0
30
11
10
15
25
15
20
12
8
32
26
0
30
13
15
51
27
20
30
14
0
19
28
15
20
15
0
27
29
15
20
16
10
12
30
35
42
17
25
35
31
10
20
32
10
20
Steady State Calibration of Field Measurements Copyright © December-2008 Bentley Systems Incorporated
19
Model Applications
Page 5-1
Model Applications and System Planning
Model Applications
Master Planning
Subdivision Planning
Preliminary Design
Setting Pressure Zones
Fire Flow Analysis
Pump Selection
Rehabilitation
Emergency Planning
Troubleshooting
Water Quality Studies
Operational Studies
Energy Management
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-2
System Profile 1000 900 Feet
800 700 600 500
Evolution of Pressure Zones 1000 ft 50 ft = 20 psi 150 ft=65 psi 300 ft = 130 psi
920 ft=35 psi Put in pressure zone boundary and pump 800 ft= 86 psi
700 ft
Put in pressure zone boundary and PRV
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-3
Setting Pressure Zones • Decisions with long-term impacts • Profile map is an excellent way to understand the system • Tank overflow - primary decision in setting pressure zones • Normal differences in elevations in pressure zones: – Less than 150 feet (50 m) / Greater than 80 feet (25 m) – Too large elev. difference results in high or low pressures – Too small results in too many tanks and difficult to operate
• Do not pump water up and then drop it through a PRV
Pressure Zone Layout Pressure Zone Boundary Contours
Future Boosted Zone Pump Station
Elevated Tank
Main Zone Reduced Zone
Boosted Zone
Ground Tank
Copyright © 2008 Bentley Systems Incorporated
PRV
Dec-08
Model Applications
Page 5-4
Master Planning Purpose: Examine the future needs of the system • Where will growth occur? • Magnitude of growth • What infrastructure will be needed? • When to invest in maintenance
Tips for Master Planning • Use system profile to better understand system • Use a skeletonized representation of system • Use constant head nodes as pumps if you do not know the pump characteristics • Look at system at different time frames • Use extended period simulations • Consider reliability of infrastructure • Do not oversize components • Consider water quality implications
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-5
Planning of expansions
Knowledge of ground uses and city-planning development future Analysis of connectivity to the existing system and other operative data Consideration of fire flows Regulatory requirements Storage versus. ample pipes Detailed design
Max Hour Design Tank Max Hour HGL Minimum HGL
Tank Refill HGL
16 Pump
12
8
6
8
12
16
Worst case may be tank refill Model refill or EPS
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-6
Pipe Sizing Overview
Layout of Proposed Piping
Demand Estimates
System Outages
Model of Existing System
Initial Selection of Sizes
Model Runs
Reformulate Design
No
No Best Costs?
Compare with standards and guidelines? Yes Estimate Costs
Yes Present to Decision Makers
Preliminary Pipeline Design • Define short-term and long-term purpose of project • Use a skeletal model of the overall system with great detail in the area being designed • Include route analysis • Consider future connections to existing/future pipes • Look at tradeoff between storage and piping • Consider peak day, peak hour and fire flow needs • Consider costs
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-7
Identifying Bottleneck Source HGL 16”
Target HGL 10” 8”
Existing HGL
10”
16” 12” 10” 8”
Subdivision Planning • Buildout relatively quick • Should consider: – internal design of the subdivision – connections to existing system – future downstream development
• Fire demands generally control the design (can test all nodes) • Avoid long dead ends
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-8
Connection to an Existing System 24 in. Proposed
? New Subdivision
6” 16”
Pipes Near Zone Boundary
Service Area Boundary
24”
Service Area Boundary 12”
12”
24”
6”
12”
24”
12”
12”
No Future Service
Copyright © 2008 Bentley Systems Incorporated
24”
Future Growth Area
Dec-08
Model Applications
Page 5-9
Adding Land Development to Existing Model 1. Modeling done with utility model 2. Modeling done with Skeletal model of existing system 3. Use result of fire hydrant flow test to simulate existing system – Do not use arbitrary fixed grade node
Simulating Existing System Elev. =Elev. of Residual Gage
Reservoir Existing System
Flow Test
Pump Proposed Development
Proposed Development
Assumptions: -Flow test is representative of future -System has not changed since the test Flow Test Results Q
P
2.31P=h
0
80
185
400
64
148
550
53
122
Copyright © 2008 Bentley Systems Incorporated
Flow
Dec-08
Model Applications
Page 5-10
Representing a Well • Problem - no “well” component in models. • Two methods of representing wells: – –
1) as a reservoir + pump OR 2) as a negative demand (inflow)
• Reservoir represents underground water surface level. • Negative demand - useful when pumping rates are relatively constant and known
Well Pumping Ground h Well
Q h Pumped Water Level
Pump Curve
Static Water Level Corrected Pump Curve
Drawdown Q
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-11
Representing Wells in Model Effective Pump
Actual
Ground
Riser Pipe
Static Level
Drawdown Node
Node
Pipe
Pipe
Reservoir
Drawdown Pumped Level
Reservoir Pipe
Pipe Pump
Pump
Pump
Which is more realistic?
Rehabilitation Studies • Upgrading existing water system • Detailed model study needed • Understand existing condition • Fire flow tests • Examination of pipes • C-factor tests • Break/Leak History • Talk with operators
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-12
Rehabilitation Options • Find closed valves • Replacement if breakage problem • New parallel pipes to increase capacity • Trenchless technology to improve capacity & reduce leakage – – – –
Clean & Line Slipline Fold and form Pipe Bursting
• New technology • Trial and error solutions
Troubleshooting • Use models to diagnose problems • Compare observations with model • Use model to explain problems – – – –
Closed/partly closed valves Control valve settings Pump not operating on curve Transient problems
• Develop solutions
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-13
Operational Studies
Real time control
Startup of new facilities
Changes in pump/valve operation
Model Operator training Preparing for shutdowns
Zone boundary changes
Station Design Flow • Based on Demand Projections • Station must meet design flow with largest unit out of service • For small stations, usually two pumps each of which can meet design flow • For large stations, multiple pumps can better meet range of demands • Staging considerations
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-14
Develop System Head Curve • Manually for simple systems • Use WaterCAD for complicated systems • Consider range of – tank levels – water usage – other pumps running
Taking Tank off Line Off-peak Demand
Normal Operating Point High Demand
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-15
Water System Head Curve
Head Low tank level
Fire or break
Flow
Force Main System Head Curve
Head
Wet weather Multiple pumps
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-16
Pump Selection Efficiency
Brake HP Flow Design Flow
Variable Speed Pumps
90%
Head, Efficiency
80%
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-17
Pump Combinations
Two Pumps
Each pump
100
200 Flow
300
400
Design Flow
Parallel Pumps Flat System Head Curve 200 180 160
Head, ft
140 120 100 80 60
Pump A Pump B
40
Flat Sys A+B
20 0 0
100
200
300
400
500
Flow, gpm
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-18
Parallel Pumps Steep System Head Curve 200 180 160
Head, ft
140 120 100 80 Pump A
60
Pump B 40
Steep Sys
20
A+B
0 0
100
200
300
400
500
Flow, gpm
Reliability • Simulate power outages (EPS) • Pipe breaks – Concentrate on major pipelines – Identify segments to be isolated – Valving important
• Acts of terrorism • Accidental contamination • Robustness of the system • Isolation valves & Criticality Analysis
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-19
Valving – Finding the weak link
12 6 12
X
16
= Valve
Cost Manager • Integrate costing with design • User must supply unit prices • Include only specified (new) elements • Included in Darwin Designer – Manual cost estimating – Since V8 SU2 – Only includes pipes
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-20
Pipe Cost Functions
$/ft
Diameter Tabular D
C1
C2
C3
6
55
42
63
8
62
47
71
10
73
56
80
…
…
…
…
Specify cost function for each laying condition (e.g. new subdivision, central City, cross country)
Using Cost Manager Identify groups to be included in costing
Enter cost functions
Create pipe groups
Design system
Assign groups to cost functions
Calculate Costs
View Reports
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-21
Optimization • Why not have model design system? • Considerable research • Difficulties – – – – – – –
Inequalities [p > P(min)] Discrete sizes Local minima Self-fulfilling prophecy Difficult to quantify reliability Handling uncertainty Real goal – not cost minimization
• Optimization will not replace good engineer • Darwin GA Optimization
Darwin® Designer Module Included in WaterGEMS - Addition in WaterCAD
• Optimization with GA • Restrictions – Partial Pressure – Speed Restrictions – Velocity
• Infrastructure – Rehabilitation – New networks
• Design Criteria – Economic multi-objective optimization – Hydraulic multi-objective
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Model Applications
Page 5-22
Detailed Steps • Start Darwin Designer • New Design Study – Set Representative Scenario – Design Group • Select Pipes for Costing by Placing in Group
– Cost/Properties • Create Cost vs. Price Tables
• Manual Cost Estimating Run – Pick groups for costing – Associate group with Cost table – Compute
The End Meet both short term and long term needs
Copyright © 2008 Bentley Systems Incorporated
Dec-08
System Design Improvements Workshop Overview In this workshop, you will receive a network in which the streets and the piping have been laid out for a new industrial park. You must resize a portion of the pipes based on a set of criteria that will be given to you.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
Workshop Objectives After completing this workshop, you will be able to:
Redesign a model
Create cost functions for Darwin Designer
Use Darwin Designer to help you with cost estimating when designing a system
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
1
Problem Statement
Problem Statement In this workshop, you will receive a network in which the streets and the piping have been laid out for a new industrial park. You must resize a portion of the pipes based on a set of criteria that is provided to you below. The network is stored in the file SystemImprovements.wtg that you can find in C:\Program Files\Bentley\WaterDistribution\Starter. The industrial park is served through existing 48 in. and 36 in. transmission mains (pipes P-1, P-31 and P-30), which is fed from a reservoir (water plant clearwell) at node R-3 and has an HGL of 971 ft. The reservoir provides water to residential areas at nodes J-17 (through a 24 in. pipe, P-29) and node J-18 (through a 36 in. pipe, P-23).
2
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Reviewing Existing Demands
Reviewing Existing Demands An engineer has assigned the demands to nodes as shown in the matrix below. Notice there are demands for average day, max day, and peak hour. These three demand alternatives have already been entered in the workshop problem for you. Note: There are no demands associated with J-5 or J-19. Demands Label
Avg Day
Max Day
Peak Hour
J-1
400
600
1,000
J-2
400
600
1,000
J-3
400
600
1,000
J-4
200
300
500
J-5
0
0
0
J-6
100
150
250
J-7
100
150
250
J-8
100
150
250
J-9
200
300
500
J-10
100
150
250
J-11
100
150
250
J-12
100
150
250
J-13
100
150
250
J-14
100
150
250
J-15
200
300
500
J-16
100
150
250
J-17
2,000
2,300
3,000
J-18
2,500
3,500
4,500
J-19
0
0
0
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
3
Reviewing Existing Demands
Exercise: Reviewing demands in the Demand Control Center 1. Start WaterCAD V8i or WaterGEMS V8i and open SystemImprovements.wtg file in C:\Program Files\Bentley\WaterDistribution\Starter. 2. Select one of the scenarios in the file as the current scenario and then select Tools > Demand Control Center. 3. In the Demand Control Center spot check that the demands in WaterCAD/GEMS match the demands listed on the previous page. Note: The demands can be sorted to match the table on the previous page by right clicking the Label column and selecting Sort Ascending.
4
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Max Day Fire Flow
Max Day Fire Flow In addition to the 3 demand alternatives that have already been set up for you, you need to also set-up an additional demand alternative with a demand of 3650 gpm on the max day at junction node J-14. This will be representing a fire occurring at junction J-14. Exercise: Creating the Max Day Fire Flow at J-14 1. To set up the alternative, select Analysis > Alternatives. 2. Highlight the Max Day demand alternative and create a child alternative by clicking the New button. 3. Name the child MaxDayJ-14Fire.
4. Double click on that alternative, select J-14, and change the Demand to 3650 gpm.
5. Create a scenario that uses that fire flow by opening the Scenarios manager, Analysis > Scenarios.
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
5
Max Day Fire Flow
6. Create a New Child Scenario from Max Day called MaxDayOrigSystFireJ-14.
7. Double click on that scenario and change the Demand Alternative to MaxDayJ14Fire.
8. Close the Scenarios manager.
6
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Pipe Sizing
Pipe Sizing Pipe Sizing Criteria You are to size the pipes in the industrial park so that the following constraints are met:
All nodes have at least 35 psi and no more than 80 psi when there is not a fire occurring at J-14. All nodes have at least 20 psi and no more than 80 psi during a fire on the max day at junction node J-14. The 48, 36, and 24 in. pipes (P-1, 23, 29, 30 and 31) are existing transmission mains, and the water authority does not want to add a tap onto them for each customer. You can only tap into this line at two points (nodes J-1 and J8 are recommended). Initially, all the pipes you must size have been set to 6 inch with a C-factor of 130. Change the diameters but not the C-factors.
Exercise: Pipe Sizing 1. You will now go through a trial and error process of sizing the pipes; to keep track of your trials, you will set up a new Physical Alternative for each new set of pipe sizes that you want to try. 2. You will put this Physical Alternative together with one of the Demand Alternatives (creating a scenario) and record your results in the table at the end of the workshop. 3. For each new set up of pipes, remember that you will need to first create and edit a Physical Alternative and then create a scenario that uses this Physical Alternative. Note: Do not record runs where you made a mistake. 4. When you have a solution that appears to meet the design criteria, determine the cost for piping in that solution.
Additional Tips
It will be helpful for you to set up color-coding of the pipes based on Diameter so that you can easily see the different pipe sizes on a plan view. Before getting started with sizing the pipes, run the base scenario to see that the pipes work for the average day flow.
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
7
Pipe Sizing
Next, run the Max Day Scenario already created. Review the pressure results for this run. Add another scenario using the Base Physical Alternative and the Demand Alternative: MaxDayJ-14Fire. Set up an additional color coding scheme based on Velocity for the Pipes. Allow WaterCAD/GEMS to initialize the colors or you can choose your own. This will help you identify bottlenecks within the system. Set up a new Physical Alternative trying as a first pass using all 8 inch pipes (excluding the transmission mains mentioned earlier) and except for a 12 inch loop made up of pipes P-2, P-15, P-3, P-4, P-5, P-6, P-7, and possibly P16. Run the new sizes using the Peak Hour and the MaxDayJ-14Fire demands since these are the scenarios that will give you the highest pressures and should be used to size the pipes. Continue trying various pipe sizes setting up a new Physical Alternative each time until you come up with a reasonable design (but not over-designed!). Record your results as you go along in the table at the end of the workshop. Set up Junction Color-Coding for Pressures (using Color and Size) based on the pressures, colors, and sizes below: Value
Color
Size
20
Red
3
35
Blue
2
80
Cyan
1
5000
Magenta
2
Note: This color coding scheme will allow you to easily see where the problem areas are once you start running the scenarios with various pipe sizes. Exercise: Setting up Color Coding 1. To set up color coding, pick View > Element Symbology. 2. Pick the type of element (e.g. Junction), right click on Junction and pick New > Color Coding. 3. When the Color Coding dialog appears, pick the property you wish to color code for from the Field Name dropdown menu (e.g. Pressure). 4. Set the number of Steps to 4. 5. Select Color and Size from the Options box and enter the information from the table above. 8
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Pipe Sizing
Note: You can also edit the Above Range Color and the Above Range Size if you would like, but it is not necessary.
6. Click Apply and then OK.
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
9
Building Cost Functions
Building Cost Functions To perform cost estimating using Darwin Designer, you must first create cost functions that contain the pricing of your different pipe diameters. Exercise: Creating cost functions using Darwin Designer 1. To do this, enter Darwin Designer by picking Analysis > Darwin Designer. 2. Within Darwin Designer, click the New button to select New Designer Study. 3. Click on the Cost/Properties tab in the right pane, click the New button and select Design Options Group. 4. Create two cost functions: one for pipes inside the development called Inside and one for pipes laid along the highway called Highway. Costs ($/ft) Diameter (in)
Inside ($/ft)
Highway ($/ft)
6
29
37
8
45
57
10
63
79
12
83
104
16
128
160
20
179
224
24
235
294
5. Rename Cost Function New Pipe-1 to Inside and fill in the cost data from the table above. 6. Set all pipes to PVC and C-factors to 130. Note: These C-factors are not used in costing. 7. Create another cost function for the pipe laid in the highway.
10
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Building Cost Functions
When completed, the cost function should look like the one below:
Exercise: Assigning Cost Functions to Design Groups Now assign pipes to Design Groups, i.e. pipes that share the same cost function. 1. Click the tab labeled Design Groups and select New. 2. Name the new group, Inside Pipes. 3. Under Element IDs column, click the ellipse (…) button next to collection to open the Selection Set dialog. 4. Click Select from Drawing button and pick all the pipes in the development (all the small pipes except P-8, P-9, P-10 and P-11). 5. Click the green check mark when done. Note: You should have 16 pipes as shown in the screen shot on the next page (though P-2 is not in the screen shot it is on the list).
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
11
Building Cost Functions
6. Click OK and repeat for the Highway Pipes which include P-8, P-9, P-10, and P11. The Design Groups tab should look like this when done:
Note: The cost data is now ready for use. 7. Be sure to save you file periodically.
12
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Calculating Piping Costs
Calculating Piping Costs This section will show you how to use Darwin Designer to calculate the costs of your scenario. Exercise: Calculating Pipe Costs in Darwin Designer 1. To calculate costs in Darwin Designer, select New Design Study – 1 in the left pane and select the Design Events tab in the right pane. 2. Select the scenario corresponding to the pipe sizes you wish to use in costing.
3. Create a manual cost estimate by clicking the New button on the left page and selecting New Manual Cost Estimate Run. 4. Assign it a name like that of the Scenario you have chosen so that you will remember the basis for the costs. 5. Make sure the box for Use Diameters from Representative Scenario is checked. 6. Check Is Active for the pipe groups to be priced and select the appropriate Cost/properties for each Design Pipe Group.
7. To start the cost estimate, click Compute complete.
and hit Close when the run is
Two new lines appear in the left pane; the one labeled Solutions displays the total cost and the line labeled Solution 1 contains a detailed breakdown of the cost for each pipe. System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
13
Calculating Piping Costs
Warning: Nothing is displayed under the Simulated Results tab because a cost run does not include any hydraulic calculations.
8. Repeat the iteration between hydraulic analysis and costing until you are satisfied that the solution meets the design criteria at a reasonable cost. 9. Fill in the Results Table after each good run. 14
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Results Table
Results Table Diameters Pipe #
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Run 7
Run 8
P-2 P-3 P-4 P-5 P-6 P-7 P-8 P-9 P-10 P-11 P-12 P-13 P-14 P-15 P-16 P-17 P-18 P-19 P-20 P-21
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
15
Results Table
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Run 7
Run 8
Avg, Max or Peak? Fire at Fire Q (cfs) Pressure (min) (psi) @ node # HGL @ node (ft) Velocity (max) pipe # Velocity (max) (ft/s) Cost ($) Check?
16
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. Explain why you selected the pipes you did.
2. Do you think the head loss in the 36 in. pipe is significant?
3. Why was node J-14 so troublesome? How did you resolve this problem?
4. Why were 6 inch pipes not seriously considered in this system?
5. Why did node J-4 give you trouble at peak hour?
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
17
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Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers Diameters
18
Pipe #
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
P-2
12
P-3
12
P-4
12
P-5
12
P-6
12
P-7
12
P-8
8
12
P-9
8
12
P-10
8
12
P-11
8
12
P-12
8
12
P-13
8
12
P-14
8
12
P-15
12
P-16
8
P-17
8
P-18
8
P-19
8
P-20
8
P-21
8
16
16 12
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Peak
Peak
Peak
Avg
Max
Max
Fire at
J-14
J-14
Fire Q (cfs)
3650
3650
Avg, Max or Peak?
Pressure (min) (psi)
29
32
37
42
-85
26
@ node #
J-4
J-4
J-4
J-4
J-14
J-14
HGL @ node (ft)
938
944
955
968
653
909
Velocity (max) pipe #
P-8
P-2
P-2
P-2
P-16
P-16
Velocity (max) (ft/s)
6.2
5.3
4.1
1.7
23.3
10.4
Cost ($)
1.802 M
2.123 M
2.344 M
2.344 M
2.344 M
2.549 M
Ok
Ok
Check?
Ok
1. Explain why you selected the pipes you did. Used trial and error to meet requirements without excess capacity.
2. Do you think the head loss in the 36 in. pipe is significant? It is not too bad in this problem.
3. Why was node J-14 so troublesome? How did you resolve this problem? It is a dead end line at a high elevation.
4. Why were 6 inch pipes not seriously considered in this system? Too much demand and high fire flows for that pipe size.
5. Why did node J-4 give you trouble at peak hour? It has the highest elevation.
System Design Improvements Copyright © December-2008 Bentley Systems Incorporated
19
Fire Protection and Fire Flow Analysis
Page 6-1
Fire Protection and Fire Flow Analysis Analyzing Fire Flows systems
Fire Protection • Secondary purpose for water system • Policy decision to provide some level of protection • Depends on who pays
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-2
Important Flows • Needed fire flow • Available fire flow – – – –
Main capacity Provide flow at minimum residual pressure (usually 20 psi) ISO uses Q20 as indicator Not “free discharge” from hydrant
http://www.isomitigation.com/downloads/ppc3001.pdf
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-3
ISO Formula
NFF = 180.5 FA 0.5O(1 + (X + P )) Where: F = class of construction A = effective area O = occupancy factor X = exposure factor P = communication factor
Needed Fire Flows • 500 to 3500 gpm – Round to 250 gpm for small flow – Round to 500 gpm for large (>2500)
• Usually 750 gpm - residential (31 - 100 ft between buildings) • Modify area, exposure, communication to reduce NFF • Duration
Length
Flow
2 hours
< 2500 gpm
3 hours
3000 – 3500 gpm
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-4
Distribution System
Hydrants SUPPLY
Available Fire Flow
Supply Works Capacity Main Capacity Hydrant Capacity
Use lowest of these three
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-5
Source Capacity
Supply Works flow
Storage flow
Peak day demand
Needed fire flow
Hydrant Distribution • 1000 gpm for hydrants < 300 ft • 670 gpm for hydrants 301 to 600 ft • 250 gpm for hydrants 600 to 1000 ft
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-6
Main Capacity from Fire Flow Test Results
Ps − 20 Q20 = Qt Ps − Pt
0.54
Where: Ps = static pressure Pt = test pressure Qt = test flow Q20 = flow at 20 psi
ISO Q20 • Approximation to what can be delivered • Assumes no head loss under static condition • Assumes no valves or pumps change status between Pt and 20 psi • Model is better estimator of flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-7
Using Model to Estimate Main Capacity • Select node for residual hydrant – Estimate Q and run model check P
• Set node to reservoir at elevation of outlet, check Q • Use WaterCAD Fire Flow Analysis • Main capacity is independent of number of hydrants
Main Capacity = 1200 gpm
B
A
C Hydrant Capacity A = 1000 gpm B= 670 C= 250
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-8
Node vs. Hydrant • Usually hydrant near node • Add node for important hydrant • Interested in main capacity in area • Q20 may be limited by hydrant availability • Nearby closed valves important
But I want to know the exact flow from a hydrant during a fire Hydrants Supply Suction Hose Hydrant Lateral If you can describe all the components, WaterCAD can calculate flow
Copyright © 2008 Bentley Systems Incorporated
Pumper Truck Discharge Lines
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-9
Main capacity corresponds to one condition • Demands
• New customers
• Time of day
• Main deterioration
• Tank water levels
• Zone boundary changes
• Pump operation • Valve operation • Pipe breaks
• Component outages • New facilities
• Power outage
Fire Sprinklers • Used to control not extinguish fire • Added to hose stream • Reduce overall NFF
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-10
Sprinkler Demand • Depends on – Building area – No. of open sprinklers
• Occupancy classification – 0.05 - 0.1 gpm/sq ft light hazard – 0.08 - 0.16 gpm/sq ft ordinary – 0.21 - 0.37 gpm/sq ft extra hazard
• 150 gpm min (commercial)
Sprinkler Demand – 2 Hose Stream Allowance • Total flow required – greater of – Sprinkler + hose stream – 500 gpm
Light Ordinary Extra Hazard
• 100 gpm • 250-500 gpm • 500-1000 gpm
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-11
Sprinkler Pressure • Generally 7 psi at every sprinkler • Use 20 psi available at riser base if no analysis done
Sprinkler Systems
Wet-pipe – full with pressurized water Anti-freeze – full with pressurized anti-freeze mix Dry-pipe – full with pressurized air Deluge – all open, controlled at main valve
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-12
Utility Evaluation • Owner provides data on needed flow and pressure • Evaluate distribution system capacity • Load model and analyze
If system inadequate • Upsize distribution piping • Upsize owner’s piping • Add fire pumps and/or storage • Reduce requirements
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-13
Sizing Sprinkler Systems • Layout piping, meters, backflow prevention • Determine sprinkler k (flow emitter) • Open sprinkler(s) • Determine discharge
Q = kP
1
2
Representing Sprinklers as Flow Emitters
Upstream Junction
Pipe Link
Flow Emitter Junction at Correct Elevation
Model will calculate flow and pressure at sprinkler
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-14
Sprinkler System Design • NFPA 13 (13D, 13R) • Start with available head • Locate critical sprinkler(s) • Tradeoff pipe size, meter size, RPBP size • Quality deterioration
Fire Insurance Rating • Fire Suppression Rating Schedule • Public Protection Class – 1 = great – 10 = terrible
• ISO • Use for all but largest cities
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-15
Determining Public Protection Class Select Test Sites Calculate NFF
Compare NFF, available FF
Hydrant maintenance
Conduct Hydrant Flow Tests
Calculate main capacity, supply capacity, hydrant distribution Water Supply
Fire Department Fire Alarms
PPC
PPC Calculations • Scoring: – 40% water supply – 50% fire department – 10% fire alarm/communications systems
• Water score – If AFF>NFF, AFF=NFF – If NFF>AFF, AFF=AFF – 35 x Sum(AFF)/Sum(NFF)
• Divergence - fire department and water supply difference
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-16
Split Classifications Single Public Protection Classification All properties receive that classification
Split classification (for example, 5/9) First class (Class 5 in the example) applies to properties within five road miles of a fire station and within 1,000 feet of a fire hydrant. Second class (Class 9 in the example) applies to properties within five road miles of a fire station but beyond 1,000 feet of a hydrant. ISO generally assigns Class 10 to properties beyond five road miles.
Distribution of Communities in the U.S. by PPC Class
ISO web site
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Dec-08
Fire Protection and Fire Flow Analysis
Page 6-17
Hydrant Discharge as Flow Emitter
Junction at Main
Lateral with minor losses
Emitter at elevation of outlet
Emitter K = 2.31 ((1/Do4-1/Dp4)/11.9g + 2.31/Cv)-1/2 Typical K (gpm,psi, in.) 2.5 in. outlet
150-180
4.5 in outlet
380-512
Modeling Hydrants
Hydrant as junction node
Hydrant element on pipe (Lateral losses part of hydrant)
Hydrant element with Lateral explicitly included
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-18
WaterCAD Fire Flow Analysis • Solves sequentially for fire flow at residual pressure at all nodes • Problems with min pressure – Pump suction – Ground tanks – Chronic low pressure nodes
Fire Flow Analysis Data • Selection set (which nodes?) • Minimum zone/system pressure – Nodes near tank – Pump suction
• Needed/max fire flow • Add needed to base • Calculation Dialog - Fire Flow Analysis
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-19
Fire Flow Analysis Analysis Restrictions
Nodes to analyze for Fire Flow
Tabular Reports
Key References • ISO Fire Suppression Rating Schedule • AWWA M-31 • ISO Fire Flow Test Procedure (AWWA M-17) • NFPA Publications
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Fire Protection and Fire Flow Analysis
Page 6-20
The End “Fire flow” means different things to different people
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Automated Fire Flow Analysis Workshop Overview In this workshop, you will evaluate the fire flows at each hydrant in a subdivision project. The overall system is shown in the Problem Statement on the next page. The new subdivision (Greendale) is in the northeast corner of the system connected by a single pipe. The needed fire flow is 750 gpm at each hydrant at 20 psi residual and a minimum zone pressure of 20 psi.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
WaterCAD/GEMS System Planning and Operation
Workshop Objectives After completing this workshop, you will be able to:
Set fire flow constraints
Perform an automated fire flow analysis
Perform an auxiliary fire flow analysis
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
1
Problem Statement
Problem Statement The overall steps will include:
Setting up a scenario for max day demand (1.5 times average day) and running it to get a feel for how the system will work under normal conditions. Setting up an automated fire flow scenario to include only those hydrants in the subdivision. Using the results of the fire flow analysis, simulate a representative fire to determine the weak links in the system. Making some improvements to the system and determining the effects on fire flows.
The file to be used for this workshop is Automated_Fire_Start.wtg.
2
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Max Day Run
Max Day Run This section is for setting up the max day demand scenario and for you to get familiar with the system. To make fire flow runs, you will need to first set up a scenario based on max day demand. Exercise: Setting up the max day demand alternative 1. Open the Automated_Fire_Start.wtg file in C:\Program Files\Bentley\WaterDistribution\Starter. 2. Open the Alternatives manager. 3. Expand the Demand Alternative category. 4. Create a child alternative from the Base-Average Daily alternative by highlighting Base-Average Daily and clicking the New button. 5. Name the new child alternative Max Day Demand.
Exercise: Creating the max day scenario 1. Open the Scenarios manager and create a child scenario from the Base Scenario by highlighting the Base Scenario and clicking on the New button. 2. Name the child scenario Max Day Base Physical.
3. With the Scenarios manager still open, right click on Max Day Base Physical and select Properties. 4. Change the Demand Alternative to Max Day Demand.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
3
Max Day Run
5. Within the Scenarios manager, right click on the Max Day Base Physical scenario and select Make Current.
Note: Notice the red check mark will be displayed next to this scenario now indicating that this is the current scenario. 6. Close the Scenarios manager. Exercise: Multiplying the demands by 1.5 and computing the max day scenario 1. Open the Demand Control Center (Tools > Demand Control Center). 2. Globally Multiply all demands by a factor of 1.5.
4
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Max Day Run
3. All of the demands should now be 1.76 gpm.
4. Click Close to exit the Demand Control Center. 5. Make sure Max Day Base Physical is still current, and then run the scenario by clicking Compute . 6. Review the results and fill in the table for the Max Day Run found at the end of the workshop. Note: The results can be reviewed using tables, color-coding, or annotation. 7. Answer the design questions that pertain to this run.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
5
Fire Flow Analysis Run
Fire Flow Analysis Run In this section you will set up and compute the fire flow scenario for the Greendale subdivision. Exercise: Reviewing pressures from max day run 1. Our fire flow minimum zone pressure requirement is 20 psi. Before setting up the fire flow run, review the pressures in the system under Max Day conditions so that you will have an idea of how the system will react to fire flows. 2. Open the Junction FlexTable. 3. Sort the Pressures in Ascending order. 4. Notice that one of the pressures is already below 20 psi. Do not be concerned with this junction as it is located on the suction side of the pump and has already been placed in a separate zone. 5. Note that all of the other junctions are above 40 psi.
6. Close out of the FlexTable.
6
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Fire Flow Analysis Run
Exercise: Creating the fire flow alternative 1. Open the Alternatives manager. 2. Expand the Fire Flow Alternative category and create a Child Alternative from Base-Fire Flow. 3. Name the child Greendale Fire Flows.
4. Edit Greendale Fire Flows and the Fire Flow data screen will appear. 5. Our analysis constraints are based on pressures, not velocity, so do not check the Use Velocity Constraint? box.
6. Set the Fire Flow (Needed) to 750 gpm, and the Fire Flow (Upper Limit) to 3500 gpm. 7. Set the Apply Fire Flows By to Adding to Baseline Demand in order to add these flows to the existing demands.
8. Continue by setting the Pressure (Residual Lower Limit) to 20 psi and the Pressure (Zone Lower Limit) to 20 psi. 9. Do not check the Use Minimum System Pressure Constraint box. 10. Let the Fire Flow Auxiliary Results Type remain at its default of None. Note: The junction nodes in Greendale already have been placed into a selection set. You need to choose it for your Fire Flow Nodes. 11. Select Greendale FF Junctions from the Fire Flow Nodes dropdown menu. Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
7
Fire Flow Analysis Run
12. The junction nodes in the table below should be listed: J-115
J-145
J-210
J-139
J-204
J-224
J-138
J-117
J-197
J-217
J-143
J-208
J-236
J-199
J-136
J-198
J-219
J-144
J-209
J-237
J-221
When finished, the Fire Flow dialog screen should appear as follows:
14. Click on Close to exit the Fire Flow dialog, and then close the Alternatives manager. Exercise: Setting up the fire flow calculation option 1. Select Analysis > Calculation Options. 2. Select Base under Steady State/EPS Solver. 3. Use the Duplicate
button to make a copy of the Base Calculation Options.
4. Enter Fire Flow Calcs for the name by clicking the Rename
8
button.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Fire Flow Analysis Run
5. Open the Fire Flow Calcs Properties window by double clicking on it. 6. Change the Calculation Type to Fire Flow.
7. Close the Calculation Options window. Exercise: Creating and computing the fire flow scenario 1. Open the Scenarios manager. 2. With the Max Day Base Physical scenario highlighted, create a child scenario called Greendale Fire Base Physical.
3. Double click on the Greendale Fire Base Physical to open its Properties. 4. Set the Fire Flow Alternative to Greendale Fire Flows and also set the Calculation Option to Fire Flow Calcs.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
9
Fire Flow Analysis Run
5. Return to the Scenarios manager. 6. Make Greendale Fire Base Physical the current scenario by right clicking on the scenario name and selecting Make Current. 7. Close the Scenarios manager. 8. On the main drawing window, click Compute
to run the fire flow analysis.
9. Close the Calculation Summary screen and save your file. 10. Review the results with the Fire Flow Report FlexTable. Note: Use the sort function to get results for the junction nodes in Greendale to come to the top of the table; these are the junction nodes that have values whereas all other junctions have N/A in the various fields. 11. Review the results and complete the Results Table for Fire Flow Analysis found at the end of the workshop. 12. Also answer any questions that pertain to this run. Hint: You may want to filter the results by Fire Flow Iterations > 0, or by Fire Flow (Available). 10
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Using Auxiliary Results
Using Auxiliary Results Now that you have found the fire flows, you would like to know which pipes have unusually high velocity and which nodes are troublesome for particular fire flows. To do this, you will use auxiliary results and the Fire Flow Results Browser. Exercise: Setting up and computing the auxiliary fire flow scenario 1. Open the Alternatives manager and create a child alternative of the Greendale Fire Flows alternative, called Greendale Auxiliary.
2. Open the Greendale Auxiliary Alternative. 3. Select All Nodes from the Fire Flow Auxiliary Results Type dropdown menu to indicate you want results to be saved for all fire flow runs. 4. Check the box for Use Node Pressure Less Than? and enter 30 psi to see any nodes that have pressures below 30 psi. 5. Check the box for Use Pipe Velocity Greater Than? and enter 5 f/s as the velocity above which you will store pipe flow results. 6. Make sure that the Fire Flow (Needed) is set to 750 gpm, the Pressure Constraints are both set to 20 psi and Greendale FF Junctions are selected for Fire Flow Nodes.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
11
Using Auxiliary Results
7. Close the alternative and create a new scenario called Auxiliary as a child of Greendale Fire Base Physical.
8. Open the Auxiliary scenario to edit its Properties. 9. Set the Fire Flow Alternative to Greendale Auxiliary. 10. Make Auxiliary the current scenario. 11. Click Compute from the toolbar and close the Calculation Summary when it comes up. 12. Browse through the Fire Flow FlexTable, it should look essentially the same as the previous fire flow run. Exercise: Reviewing results using the fire flow results browser Now you will use the Fire Flow Results Browser to look at auxiliary results. 1. Select Analysis > Fire Flow Results Browser and you will see the dialog below:
12
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Using Auxiliary Results
Note: This indicates that all the fire flows passed, but you would like to see the marginal nodes and pipes. 2. Open the Junction FlexTable. 3. Right click on the Pressure column and select Sort > Sort Descending. 4. Click on any junction node in the Fire Flow Results Browser and you will see the results update in the Junction FlexTable. Note: You will see results for all nodes from the Greendale FF Junctions set which have pressure below 30 psi.
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
13
Using Auxiliary Results
Note: Above shows results for when J-115 is selected in the Fire Flow Results Browser. 5. Close the Junction FlexTable and open the Pipe FlexTable. 6. Sort the Velocity column in Descending order and you will only see results for pipes with high velocity and the pipes connected to the selected fire flow node.
Note: Above shows results for when J-136 is selected in the Fire Flow Results Browser. WaterCAD/GEMS does not save results for pipes that do not meet the velocity criteria except for the pipes that are connected to the fire flow node. 7. Fill in the Results Table at the end. 8. If you go back to the Fire Flow Results Browser and pick some other fire flow junction node, you will see the results change in the Pipe FlexTable. 14
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Using Auxiliary Results
9. If you have additional time, use color coding to see which pipes are critical for each fire flow node. Exercise: Color coding critical pipes 1. Select View > Element Symbology and uncheck the Diameter color coding for the pipes.
2. With Pipe highlighted, click the New button and select New Color Coding. 3. Select Velocity for Field Name. 4. Select Color and Size from the Options dropdown menu. 5. Set the following: Value
Color
Size
6
Blue
4
10
Green
4
20
Red
4
6. Click Apply and then OK. Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
15
Using Auxiliary Results
7. Now that you are color coding by velocity (only for those pipes that have velocity greater than 5 f/s (as set in auxiliary results), you can step through the fire flow nodes in the Fire Flow Results Browser and look at the high velocity pipes for each fire flow. 8. Try zooming to the new development portion of the system to better see the pipes.
16
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Results Tables
Results Tables Max Day Base Physical Scenario Junction Node
Pressure (psi)
HGL (ft)
J-83 J-114 J-138
Fire Flow Analysis – Fire flow analysis run with the existing distribution system Node
Fire Flow (Available) (gpm)
Pressure (Calculated Residual Lower Limit) – Pressure at Fire Flow Node (psi)
Junction with Minimum Pressure (Zone)
Calculated Minimum Zone Pressure (psi)
J-115 J-136 J-197 J-237
Auxiliary Results Pipe Data – List Pipes with Velocity Greater than 10 ft/s when fire flow node is J-115. Pipe Number
Flow (gpm)
Velocity (ft/s)
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
17
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. In reviewing the pressures from the max day steady state run, what would you conclude about the pressures in this system?
2. In the fire flow analysis for this system the node which limited the fire flow was not near the fire, why was this the case?
3. Is this typical for most systems?
4. What pipe(s) had the highest velocity and were most responsible for limiting fire flows?
5. What was the source of the water during the Max Day run vs. the source for the Fire Flow run?
18
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Answers Max Day Base Physical Scenario Junction Node
Pressure (psi)
HGL (ft)
J-83
41
1829
J-114
93
1828
J-138
139
1828
Fire Flow Analysis – Fire flow analysis run with the existing distribution system Node
Fire Flow (Available) (gpm)
Pressure (Calculated Residual Lower Limit) – Pressure at Fire Flow Node (psi)
Junction with Minimum Pressure (Zone)
Calculated Minimum Zone Pressure (psi)
J-115
1114
21
J-114
20
J-136
1708
60
J-83
20
J-197
1197
20
J-144
22
J-237
1708
31
J-83
20
Auxiliary Results Pipe Data – List Pipes with Velocity Greater than 10 ft/s when fire flow node is J-115. Pipe Number
Flow (gpm)
Velocity (ft/s)
P-162
1202
13.63
P-163
1198
13.59
P-164
1196
13.57
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
19
Workshop Review
1. In reviewing the pressures from the max day steady state run, what would you conclude about the pressures in this system? Pressures are generally quite high. More than half of the node pressures are greater than 90 psi.
2. In the fire flow analysis for this system the node which limited the fire flow was not near the fire, why was this the case? High points other than at the flowed hydrant can control available fire flow.
3. Is this typical for most systems? This is not typical of systems in flatter terrain.
4. What pipe(s) had the highest velocity and were most responsible for limiting fire flows? Non-looped pipes had the highest velocity (e.g. P-162, P-163, and P-164). However for some cases, head loss back in the other part of the system controlled fire flow.
5. What was the source of the water during the Max Day run vs. the source for the Fire Flow run? Max day flows came from the pump while fire flows came primarily from the tank. Pumps are limited by their curve.
20
Automated Fire Flow Analysis Copyright © December-2008 Bentley Systems Incorporated
Extended Period Simulation
Page 7-1
Extended Period Simulation Running water models over time
Extended Period Simulation (EPS)
EPS
• • • •
Tracks a system over time Is a series of linked steady-state runs Models pump and tanks cycle(s) Excludes transient (water hammer) analysis
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-2
Why Use EPS? • Water system operations change over time: – – – –
Demands vary over the course of a day Pumps and wells go on and off Valves open and close Tanks fill and draw
• Design tank volume • Virtually test pump operation • Provide operator training • Design for energy minimization • Perform water quality analysis
Data Changing Over Time p
h pressure gage
time
time
tank
tank
flow gage
q time
Copyright © 2008 Bentley Systems Incorporated
h time
Dec-08
Extended Period Simulation
Page 7-3
Data Changing Over Time Water usage
Tank water level Pumpage rate Flow through PRV 0:00
6:00
12:00
18:00
24:00
Time of day
Using an EPS Model Simulate: • Peak day • Minimum day • Average (modal) day
• Answer these questions and more: – – – –
Are Are Are Are
pumps cycling on and off too much? tanks exercising too little? pressures out of or under range? velocities reasonable?
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-4
Can Simulate These… • Fires • Pipe breaks • Energy costs • Power outages • Tank out of service • Shutdown for rehab or connection • Unusual demands • Use your imagination
Determine Energy Costs • Energy cost = k Q h p/e – Q = flow, h = head, p = price, e = efficiency
• Calculates – – – – – – – – –
Water power, hp Brake horsepower, hp Wire power, hp Power used, kwhr Efficiency, % Energy cost, $ Demand cost, $ Storage cost, $ Unit costs, $/MG
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-5
EPS Simulation Process
Initial conditions
Data entry
Results
Yes
First time step
Last step?
Solve network
Check controls
No
EPS Input Steady State input Pump and valve controls
Initial tank water levels
EPS Input Water use patterns
Tank xsections Duration and time step
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-6
Time Scales • Duration – Length of EPS – 24, 48, 72 hours – Run for several cycles
• Time step – Smaller steps give better resolution – 1 hour typical
• Depends on scale of problem – Water distribution – 1 hour step for 72 hours – Hydropneumatic system – 10 min step for 2 hours – Reservoir – 1 day step for 3 months
Water Use Patterns • Temporal variations in water usage – i.e. diurnal curve • Literature values can provide first guess – very system specific • Define patterns by demand types: – example: residential / industrial / commercial • For large water users, use actual water use patterns • Patterns can vary by season/day of week • SCADA useful in estimating system-wide temporal water use patterns • Data logging is useful
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-7
Using Demand Patterns • Patterns are made of a series of multipliers • Assign patterns to nodes – Few patterns, many nodes
• Can have composite nodes with several patterns • Patterns repeat if duration exceeds pattern
Flow Time
Importing Demand Patterns Tab Delimited File
Time
Pattern 1
Pattern 2
0
0.9
0.6
1
0.8
0.7
2
1.0
0.8
3
1.2
1.3
4
1.4
1.6
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-8
Patterns: Stepwise or Continuous STEPWISE
CONTINUOUS
TIME
Typical Demand Factors
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-9
Flow Balance For given time period: Usage = V(in) – V(out) +/- ΔStorage Define area where all flows and levels are known
Demand = Usage/Time Multiplier = Demand/(Average Demand)
System-wide Temporal Water Use
Tank Water Level
Pump Rate
Slope of tank water level curve defines usage rate. Example: For a 100 foot diameter cylindrical tank that empties at 0.5 feet per hour (feet/hr) X (x-sectional tank area) = Usage rate
500 +/-
Usage = 0.5 ft/hr X 7850 ft2 = 3925 ft3/hr = 489 gpm
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-10
Data Collection
Flow
Level
Small errors in tank level (H) can cause errors in Q – Q=A (dh+error)/dt
Use average flow rate during time step “Instantaneous” vs. “average”
Time
Data for Energy Analysis • Good EPS run • Energy costs (time of day) • Efficiency curve – Constant efficiency – Piecewise – BEP
e
Flow
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-11
Controls
Operational Controls • Property of a controlled element • Limited to a single condition/action
Logical (rule based) Controls • Kept with logical alternatives • Complex conditions/actions
Specifying Node Controls Example Off at 450 ft On at 440 ft Pump 1 Initial Status = on Controlled by Tank - 1 Tank - 1
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-12
Controls: Operating Rules • Must tell model how pumps and valves operate • Status (digital): – Pipe: Open or Closed – Pumps: On or Off – Valves: Active, Inactive (pipe) or Closed
• Setting (analog): – Pumps: Relative speed factor – Valves: Pressure, flow or headloss coefficient
Logical (Rule Based) Controls • Controls made up of conditions and actions • IF (condition is true) • THEN (action) • ELSE (action) • IF (Flow at P-17 > 200) THEN (PMP-1 = on) ELSE (PMP-1 = off)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-13
Conditions • Element (HGL at J-11 > 145) • Time from start (T >= 7) • Clock time (Clock Time < 7:00 am) • System demand (Demand > 500)
Composite Conditions and Actions • Flow > 200 AND Clock Time > 3:00 pm • PMP –1 = off AND P-11 = open • Each action and condition has label • IF (CC01 AND CC02) THEN (AA03 AND AA05) • Can find references for each action or condition
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-14
Setting Logical Controls
Define conditions and actions
Create controls
Create control sets
Specify control set (operational alternatives)
Control Priority • Can set priority of control • 1 = high priority, 5 = low • Default = lowest • If conflict – execute highest priority – first on list if same
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-15
Understanding Controls • What do you have in your system? – – – – –
Local PLC, RTU Centralized SCADA Manual control Combination Determine rules from operators
Tanks
Ground Storage
Stand Pipes
Elevated tanks
Hydropneumatic
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-16
Matching Tank Levels, Flows, Pressures 1. Start with good static calibration parameters 2. Set up and Run model in Extended Period Simulation (EPS) 3. Compare model results to field measurements 4. Adjust model parameters to accurately match observed field data
Tank Data Define tank cross-sectional area.
– Tank cross section may be constant at different depths (e.g. cylinder). – Tank cross section may vary over depth (e.g. pedespheroid).
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Dec-08
Extended Period Simulation
Page 7-17
Tank Volume vs. Depth
Tank Levels
850
Maximum
30
150
845
Initial
25
145
0
120
820
Minimum
LEVEL Base = 820
ELEVATION 700
Base
LEVEL Base = 700
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Dec-08
Extended Period Simulation
Page 7-18
Tank Volumes Equal Equal
Average Town
Fire
Small Town
Fire
Equal
Major City
Equal Emergency
Rural System
Emergency
Tank Sizing Equalization (~10-20 % max day)
Time
Fire (Max Day+ Fire - Production) Emergency (Duration x Demand) Volume = Equalization + max{Fire, Emergency}
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Dec-08
Extended Period Simulation
Page 7-19
Tank Water Level 30
C
20
A
D
B
0
10
Water Level
E
0
12
24
36
48
60
72
Time of Day
Simulating Tank in Design
Min Day
HGL
Ave Day
Max Day
Time
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Dec-08
Extended Period Simulation
Page 7-20
Multiple Tanks Control Valve Min Use
Ave Use 2010
2015
Max Use
Water Level
Simulate Fire
Fire Recovery
Time
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-21
What are Hydropneumatic Tanks? • Pressurized tank (typical 1,000-10,000 gal) • Filled with air & water • Store energy as compressed air • Gas vessel/bladder tanks/surge tank
Hydropneumatic Operations • Pump to tank compresses air/stores water • Pump kicks off at high pressure • Compressed air balances system pressure • At low pressure pump kicks on
Effective Volume
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Dec-08
Extended Period Simulation
Page 7-22
How are Hydropneumatic Tanks Used? • Options – – – –
Constant speed pump Variable speed pump Elevated tanks + pump Hydropneumatic tank + pump
• Small systems where elevated storage is not practical or feasible • Handles wide range of flows but limited in volume • Large energy savings possible
How to Model Hydropneumatic Tanks • Steady model – As Fixed HGL – As Fixed outflow
• EPS model – Using Gas Law (Method #1) – Using Constant area tank (Method #2)
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Dec-08
Extended Period Simulation
Page 7-23
Modeling Hydropneumatic Tanks Gas Law - Method #1
Ideal Gas Law
pV(gas) = nRT = Constant =K Boyle’s Law V(gas) = K/(P+Patm)
Gas Law vs. Effective Area
Hoff Effective Volume Hon Hmin
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-24
1000 gal - Op 200 to 600 gal 200
Pressure, psi
160
Gas Law Equivalent
120
Effective Volume
Con
80
Pressure Range
40
0 0
200
400
600
800
1000
Vol, gal
Hydropneumatic Tank Options Constant equivalent area tank • Input – – – –
Elevation HGL on / HGL off Effective volume Controls for associated pump
• Output – HGL fluctuations – Total volume is user responsibility
Gas law tank • Input – – – –
Elevation Initial HGL and liquid volume Total volume Controls for associations pump
Copyright © 2008 Bentley Systems Incorporated
• Output – HGL fluctuations – Effective volume for given pressure range
Dec-08
Extended Period Simulation
Page 7-25
Modeling Hydropneumatic Tanks Constant Area - Method #2 H2 = z + 2.31 P2 V
A = Veff / (H2 – H1) V
H2 H1
H1 = z + 2.31 P1
Pressure Switch Elev. - z
Calibrating an EPS Model 1. Start with well calibrated steady-state model 2. Compare – – – –
tank water levels pressure recorders flow meters actual valve operation
3. Look at different seasonal and water usage situations 4. Consider tracer studies – provide insights
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Dec-08
Extended Period Simulation
Page 7-26
Calibration Plots
field data points poor agreement
Tank Water Level
Good agreement
Time
Multiplier
Validate Model with Other Days
20% variation between days
Time of Day
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Dec-08
Extended Period Simulation
Page 7-27
Adjustments for EPS • If tank slope in wrong direction, pump or valve controls wrong • If tank slope of wrong magnitude, demands wrong • Difficult to find roughness or closed valve
Tracer Tests • Uses an EPS water quality model to adjust hydraulic parameters • Accurate hydraulic model can predict movement of conservative substance through network • Must vary concentration of tracer
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-28
Fairfield CA Rancho Solano Zone III
Fluoride matched relatively well at most stations. At Sampling Station F006
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-29
Very poor match at station F015. Predicted low-fluoride front arrived much sooner than observed results.
Solution: by trial and error it was surmised that partially closed valve existed in pipe near to station F015. Results improved significantly.
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Extended Period Simulation
Page 7-30
Assessment of Tracer Method • Good for demand errors and closed valves • Relatively few tracer studies done • Usually quite labor intensive • Low cost recording monitors would make method more practical • Potentially more accurate than standard calibration techniques
Reporting Time Step (Calc Option) • Saves results for all time steps (default) • Can save only at a constant increment • Can save at variable increments – Can skip range of time steps – Can save at constant or all times steps in some range
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Extended Period Simulation
Page 7-31
Results File Path • Results saved with .mdb by default • May want to save results files elsewhere • Can specify alternative path in – Tools>Options>Project – Specify Custom Results File Path?
• Some results files – – – –
.OUT main results file .NRG energy cost results .SEG segmentation analysis .RPC messages
The End Systems are inherently unsteady
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Copyright © 2008 Bentley Systems Incorporated
Variable-Speed Pumping and Energy Costing Analysis Workshop Overview In this workshop you will compare the energy costs for three different pump operating strategies. You will compare these different operating strategies by setting up and running a 24-hour Extended Period Simulation (EPS) for each one.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
WaterCAD/GEMS System Planning and Operation
Workshop Objectives After completing this workshop, you will be able to:
Set up and compute an extended period simulation
Model variable speed pumps
Create and apply element controls
Perform an Energy Cost Analysis
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
1
Problem Statement
Problem Statement In this workshop, you will compare the energy costs for following three different pump operating strategies:
Constant-speed pumping with storage Constant-speed pumping without storage Variable-speed pumping without storage
You will make this comparison by setting up and running a 24-hour EPS simulation for each operating strategy. The network layout and most of the input data have already been entered into the file EPS.wtg.
You will need to enter the demand pattern (continuous type) given below and assign this pattern to all of the node demands for every scenario.
2
Hour
Multiplier
0
0.8
3
1.0
6
1.2
9
1.4
12
1.2
15
1.0
18
0.8
21
0.6
24
0.8
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Problem Statement
The pump efficiency curve for both pumps under all scenarios is described by:
Efficiency Type: Best Efficiency Point Motor efficiency = 95% BEP efficiency = 75% BEP Flow = 15 MGD
For all operating strategies, PMP-4 is initially ON and PMP-5 is OFF. The operating strategies for the three scenarios are given below. Scenario 1: Tank Control Tank levels for pump switches are shown in the following table: On if T-1 HGL (ft) is <
Off if T-1 HGL (ft) is >
PMP-4
350
359
PMP-5
345
355
Scenario 2: Constant speed/no tank
PMP-4 is always on. PMP-5 comes on when flow in P-18 is greater than 15 MGD; else, PMP-5 is off. T-1 and P-16 are inactive for this scenario.
Scenario 3: Variable speed/no tank
PMP-4 is a variable speed pump, which is always on and set to maintain a target head of 380 ft at J-1. The maximum relative speed is 1.0. The controls on PMP-5 are the same as those used in Scenario 2. T-1 and P-16 are inactive for this scenario.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
3
Getting Started
Getting Started You will be using an existing WaterCAD/GEMS file named EPS.wtg. This file includes the layout of the system with a base physical scenario for which node demands, elevations, pipe, pump, and tank characteristics have already been entered. You will need to finish entering the rest of the data to get the model set up for the different scenarios. Exercise: Entering demand data 1. Select Components > Patterns. 2. In the Patterns dialog, click on Hydraulic, and then select the New button. 3. Instead of accepting the default name Hydraulic Pattern-1, rename the pattern to Diurnal. 4. Enter a Start Time of 12:00:00 AM and a Starting Multiplier of 0.8. 5. Set the Pattern Format to Continuous. 6. Complete the pattern as shown below:
4
Hour
Multiplier
3
1.0
6
1.2
9
1.4
12
1.2
15
1.0
18
0.8
21
0.6
24
0.8
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Getting Started
7. Close the Patterns manager. Exercise: Assigning the demand pattern to demand nodes 1. Assign the diurnal demand pattern to each of the demand nodes by selecting Tools > Demand Control Center. 2. Right click on the Pattern (Demand) column header and select Global Edit. 3. Select Diurnal for the Value.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
4. Click OK and click Close to return to the drawing pane. Next, you must define the efficiency curve for each pump. Exercise: Entering pump efficiency data 1. Select Components > Pump Definitions to enter the Pump Definitions manager. Note: Notice that there are currently two pumps defined.
2. Highlight Pump Definition – 3 (PMP-4), select the Efficiency tab and enter the following: Pump Efficiency
Best Efficiency Point
BEP Flow
15 MGD
BEP efficiency
75%
Note: The pump efficiency curve is displayed as the red line.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Getting Started
3. Select the Motor tab and set the Motor Efficiency to 95%. 4. Enter the same Efficiency data for Pump Definition-2 (PMP-5). Exercise: Setting pump initial conditions 1. For all scenarios, PMP-4 is initially ON and PMP-5 is initially OFF. Note: These can be easily set in the Pump FlexTable. 2. Open the Pump FlexTable and set those conditions using the Status dropdown menus.
Hint: You may need to Edit the FlexTable to add Status (Initial) as a column in the FlexTable. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
Exercise: Setting the calculation options You are going to analyze this system using 24-hour extended period simulation runs so you need to set the Calculation Options up for that type of analysis. 1. Select Analysis > Calculation Options. 2. Make sure Steady State/EPS Solver is highlighted and click the New button. 3. Name the new calculation option 24-Hour EPS.
4. Adjust the properties of 24-Hour EPS as follows: Base Date:
Enter today’s date
Time Analysis Type:
EPS
Start Time:
12:00:00 AM
Duration (hours):
24
Hydraulic Time Step (hours): 1.0
5. Close the Calculation Options dialog. 6. Save your file.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 1: Tank Control Scenario
Scenario 1: Tank Control Scenario You will now set up controls for the first Scenario described in the Problem Statement. All of the controls will be set up through Components > Controls. In the Controls dialog, you can set up the controls directly, or build Conditions and Actions individually and then combine them to make controls. New in WaterCAD/GEMS V8i is the Control Wizard which we will use in this training. Exercise: Setting up the tank control conditions 1. Select Components > Controls. 2. On the Controls tab click the Control Wizard
button.
3. Select the following from the associated dropdown menus in the Control Wizard dialog to enter the controls for PMP-4: Pump:
PMP-4
Tank:
T-1
On Operator:
<
On HGL (ft):
350
Off Operator:
>
Off HGL (ft):
359
4. Click the New button and add the following controls for PMP-5. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 1: Tank Control Scenario
Pump:
PMP-5
Tank:
T-1
On Operator:
<
On HGL (ft):
345
Off Operator:
>
Off HGL (ft):
355
5. Click the Create button when you are done. Note: When you click Create the Control Wizard enters the different Conditions and Actions of the controls that you entered into their associated tabs on the Controls dialog and builds the controls for you. 6. You should now see four controls listed on the Controls tab of the Controls dialog.
7. Click on the Conditions and Actions tab to review what the wizard did.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 1: Tank Control Scenario
Note: These four logical controls are needed for the first scenario, in which the pumps are controlled by tank level. We are going to group them into a Logical Control Set. Exercise: Creating a logical control set 1. Select the Control Sets tab and click on the New button to open the Logical Control Set dialog.
2. Move all four controls from the Available Items pane to the Selected Items pane by clicking the Add All
button.
3. Click Close when done. 4. Right click on Logical Control Set-1 and select Rename. 5. Give it a name of Tank Controls.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 1: Tank Control Scenario
6. Close out of the Controls dialog when you are done. 7. Save your file. Exercise: Creating the control alternative 1. To create a new alternative and scenario named Tank Control that incorporates the logical controls you just created, first go to the Alternatives manager and expand the Operational Alternative category. 2. Create a child alternative from Base-Operational Controls. 3. Name the new child alternative Tank Control Operations.
4. Open the Tank Control Operations Alternative. 5. Select Tank Controls from the dropdown menu for Control Set.
6. Click Close. Exercise: Creating the tank control scenario 1. Open the Scenarios manager. 2. Add a child scenario to Base named Tank Control Scenario.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 1: Tank Control Scenario
Note: This scenario will use the base topology, physical, demand and initial conditions alternatives. 3. Open the Tank Control Scenario and set the Operational Alternative to Tank Control Operations and the Calculation Option to 24-Hour EPS.
4. Close the Scenarios manager. Exercise: Computing the tank control scenario 1. Make Tank Control Scenario the active scenario. 2. Click Compute
.
3. Review the Calculation Summary results. Note: The buttons for every time increment should be green.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 1: Tank Control Scenario
4. Close the Calculation Summary. Exercise: Using graphs to compare junction pressures 1. Click on the Graphs 1, J-3 and J-9.
button to create a graph to compare pressures at nodes J-
2. Select the down arrow next to the New button and select Line-Series Graph. The Select toolbar appears with the Add
button already selected.
3. Select junctions J-1, J-3 and J-9 on the drawing pane, then select Done
.
The Graph Series Options dialog appears. 4. Select Pressure and uncheck Hydraulic Grade for the Fields. Your screen should look as shown on the next page.
14
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 1: Tank Control Scenario
5. Click OK to generate the graph.
6. Use the Chart Settings
button to enhance the appearance of your graph.
7. Arrange the information listed in the legend so the nodes are in ascending order, left to right. Note: Use the
and
buttons to rearrange the legend.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 1: Tank Control Scenario
8. Change the graph to 3-D by clicking on the 3-D tab. 9. Put a check mark in the 3 Dimensions box, select Best Quality from the Quality dropdown menu.
10. Click Close to exit out of the Chart Options dialog.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 1: Tank Control Scenario
11. Close the graph and rename it Junction Pressures.
12. Save your file. Exercise: Graphing a pump’s flow over time Now, create another graph of pump PMP-4 flow over time. Note: On the drawing nodes J-1, J-3 and J-9 may still be highlighted. 1. Click on PMP-4 to highlight it instead of the junctions. 2. Then click the New button from the Graphs dialog and select Line Series Graph. Again, make sure the correct Scenario, Element, and Field are checked. Note: You can use Flow (Total) or Flow (Absolute) to plot pump flows. 3. Select OK to view the graph. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
17
Scenario 1: Tank Control Scenario
4. Enhance the graph appearance if you like the 3-D look.
5. Close this graph and rename it Pump PMP-4 Flow. 6. Complete the column in the Results Table for the With Tank scenario. 7. Results can be found using graphs or tables. Note: For each run, wait until later in the workshop to answer the energy cost questions. Computing energy cost will be addressed in detail after you have set-up all 3 scenarios.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 2: Constant-Speed Pump with no Tank
Scenario 2: Constant-Speed Pump with no Tank The next two scenarios will model the system with no storage tank. To do this within the same model file without losing any data, you will need to set up an alternative topology—one without T-1 and P-16. Exercise: Creating an active topology alternative 1. To make T-1 and P-16 inactive, go to the Alternatives manager and expand the Active Topology category. 2. Add a child alternative to Base-Active Topology and name it No Tank.
3. Edit No Tank. 4. On the Pipe tab, uncheck the Is Active? box for P-16.
5. On the Tank tab, uncheck the Is Active? box for T-1.
6. Click Close. 7. Close the Alternatives manager. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
19
Scenario 2: Constant-Speed Pump with no Tank
Exercise: Creating a new control condition You must now set up a new logical control set for this scenario. PMP-4 will remain on at all times in this scenario because there is no storage. Under higher flow conditions, it may be necessary to run PMP-5 as well. Set up a control that will turn PMP-5 on when the flow in P-18 is greater than 15 MGD. 1. Select Components > Controls and pick the Conditions tab. 2. Click the New button and select Simple. 3. Set the parameters as listed below: Condition Type:
Element
Element:
P-18 (click the ellipsis and select from drawing)
Pipe Attribute:
Flow
Operator:
>
Discharge:
15 MGD
Exercise: Creating the new control Because you have already created the Actions (PMP-5 = On) and (PMP-5 = Off), you do not need to recreate them. 1. Go directly to the Controls tab, click New, and set the following: IF Condition: (P-18 Flow > 15 MGD) THEN Action: (PMP-5 = On) ELSE Action:
20
(PMP-5 = Off) (check the Has Else? box to activate option)
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 2: Constant-Speed Pump with no Tank
Exercise: Creating the new control set 1. Select the Control Sets tab and click on New. 2. Add only the Control for pipe P-18 flow that you just created using the single Add button. 3. Click OK and rename this Control Set No Tank. Note: It should only contain one control.
4. Close the Controls dialog. Exercise: Creating a new control alternative 1. Go to the Alternatives manager and expand the Operational Alternative category. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 2: Constant-Speed Pump with no Tank
2. Add another child to Base-Operational Controls and name it No Tank Operations.
3. Open No Tank Operations and select No Tank as the Control Set.
4. Click Close. Exercise: Creating and computing the new scenario A new scenario is needed that uses this new control. 1. Open the Scenarios manager, highlight Base, and click the New button and select Child Scenario. 2. Name it No Tank Constant Speed. 3. Assign this new scenario the Active Topology No Tank; Operational control set No Tank Operations and Calculation Options 24-Hour EPS.
22
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 2: Constant-Speed Pump with no Tank
4. Close the Scenarios manager and make No Tank Constant Speed the active Scenario. 5. Compute this scenario and check the results to make sure that there are no warnings. 6. Close the Calculation Summary. 7. Go back to your graphs and view the pressure comparison graph you created in the last scenario. Note: Make sure No Tank Constant Speed is the selected scenario in the Graph Series Options dialog box. 8. Fill in the Results Table and answer the questions for this scenario.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
23
Scenario 3: Variable-Speed Pump with no Tank
Scenario 3: Variable-Speed Pump with no Tank The variable speed pump scenario will use the same active topology and operational controls as the constant speed scenario, so it will be created as a child of that scenario. The only change between the two runs is that the lead pump, PMP-4, will now be a variable-speed pump (VSP). Exercise: Creating a new physical alternative Change PMP-4 to a variable-speed pump by creating a new physical alternative called Variable Speed. 1. Go to the Alternatives manager and expand the Physical Alternative category. 2. Add a child to Base-Physical named Variable Speed.
Note: Make no more modifications here; we will modify this alternative from the drawing. Exercise: Creating the no tank variable speed scenario 1. Go to the Scenarios manager and add a child to No Tank Constant Speed named No Tank Variable Speed.
2. Change its Physical Alternative to Variable Speed.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Scenario 3: Variable-Speed Pump with no Tank
3. Close the Scenarios manager. Exercise: Changing PMP-4 to a VSP 1. On the main window make No Tank Variable Speed the active scenario. 2. Double click on PMP-4 to edit its pump properties. 3. In the Physical category, change Is Variable Speed Pump? to True. 4. Set the following: VSP Type
Fixed Head
Control Node
J-1
Hydraulic Grade (Target) (ft)
380
Relative Speed Factor (Maximum)
1.0
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Scenario 3: Variable-Speed Pump with no Tank
Exercise: Computing and reviewing the variable speed scenario 1. Make sure No Tank Variable Speed is the active scenario and Compute it. You can get an overview of how the operations of the pumps affect pressures by looking at junctions J-1 and J-3. 2. In the Graphs dialog, create a new Line-Series Graph. 3. Select J-1 in the drawing. 4. In the Graph Series Options dialog select Pressure and check all three boxes for your scenarios: Tank Control Scenario, No Tank Constant Speed, and No Tank Variable Speed. 5. Click OK to view the graph.
6. Enhance the graph appearance if you like. 7. Fill in the Results Table and answer questions for this run. Note: You can use the Data tab and column sort functions to help find minimum and maximum pressures. 8. Close the graph and give it a descriptive name. 9. Repeat these steps for junction J-3. 10. Complete the rest of the first Results Table. 26
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Energy Cost
Energy Cost Now you are going to calculate the energy cost for each scenario. Exercise: Setting up energy costs 1. Select Analysis > Energy Costs. 2. Click the Energy Pricing Pricing dialog.
button and then click the New button on the Energy
3. Rename this Energy Pricing data Uniform Energy Price. 4. Enter a Start Energy Price of $0.10/kWh with no demand charge. 5. Enter the same price, $0.10/kWh at 24 hours.
6. Click Close on the Energy Pricing dialog. 7. Stay in the Energy Cost dialog and select the Tank Control Scenario. 8. Include PMP-4 and PMP-5 in the energy calculations and assign Uniform Energy Price in the Energy Pricing column. Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Energy Cost
9. Click the Compute button on the Energy Costs dialog and record the daily pumping cost. 10. Review energy cost information and pump/storage details. 11. Then select the No Tank Constant Speed scenario, compute it, and record the daily cost. 12. Finally, do the same for the No Tank Variable Speed scenario. 13. When finished, exit the Energy Cost dialog. Exercise: Reviewing Wire-to-Water Efficiencies The next results to review are Wire-to-Water Efficiencies and Pump Heads. 1. Create a new Line-Series Graph for pump PMP-4. 2. On the Graph Series Options dialog, set the Scenario to Tank Control Scenario and the Fields to Wire to Water Efficiency found under the Results (Energy Costs) section. 3. Click OK to view the graph.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Energy Cost
4. Review the graph and the Data tab. 5. Record the range of efficiencies in the Results Table. Note: Do not use a minimum efficiency value that occurred when the pump is off. 6. Change the graph to show Pump Head, and record the minimum and maximum pump operating heads.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Energy Cost
Note: Record head values that occurred when the pump is running. 7. Use the graphing capabilities to obtain the wire-to-water efficiencies and pump heads for the other two scenarios. 8. You may use this existing graph and adjust the scenario, or you can create additional graphs. Hint: An effective procedure for comparing results is to plot multiple scenarios on one graph.
9. Complete the results table and finish the questions.
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Results Table
Results Table Please use graphs and data tables to complete the results table with approximate values. Do not record zero hour values. Complete this first table after the extended period simulation runs. Attribute
With Tank
No Tank Constant Speed
No Tank Variable Speed
Max Pressure J-1 (psi) Min Pressure J-1 (psi) Max Pressure J-3 (psi) Min Pressure J-3 (psi)
After you complete the energy costing runs, fill in the table below. Attribute
With Tank
No Tank Constant Speed
No Tank Variable Speed
Max W-to-W Efficiency PMP-4 (%) Min W-to-W Efficiency PMP-4 (%) Max Head PMP-4 (ft) Min Head PMP-4 (ft) Daily Energy Cost ($)
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. In the tank control run, why does the pressure vary more at J-1 than J-3?
2. In the variable speed pump run, why does pressure vary more at J-3 than J-1?
3. What is the number of pump starts during the day for the scenario with the tank? Is it excessive?
4. Do you think the pumps have enough capacity for this application?
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Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Workshop Review
5. Which scenario had the lowest energy costs? Which do you think would have the lowest life-cycle cost?
6. Why was the energy use for the no tank constant head scenario the greatest? What did the other two scenarios do to lower costs?
7. What was the range of relative speeds for the variable speed pump? If the target head were increase, how do you think the speed would change?
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
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Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers
34
Attribute
With Tank
No Tank Constant Speed
No Tank Variable Speed
Max Pressure J-1 (psi)
84
102
78
Min Pressure J-1 (psi)
59
91
78
Max Pressure J-3 (psi)
70
100
76
Min Pressure J-3 (psi)
64
85
72
Attribute
With Tank
No Tank Constant Speed
No Tank Variable Speed
Max W-to-W Efficiency PMP-4 (%)
71
69
70
Min W-to-W Efficiency PMP-4 (%)
70
44
49
Max Head PMP-4 (ft)
179
216
164
Min Head PMP-4 (ft)
169
195
161
Daily Energy Cost ($)
691
986
730
Variable-Speed Pumping and Energy Costing Analysis Copyright © 2008 Bentley Systems Incorporated
Workshop Review
1. In the tank control run, why does the pressure vary more at J-1 than J-3? The tank tends to keep pressure constant. The cycling of pumps affects J-1 the most because of location.
2. In the variable speed pump run, why does pressure vary more at J-3 than J-1? Pressure is controlled to be constant at J-1.
3. What is the number of pump starts during the day for the scenario with the tank? Is it excessive? 5, not excessive.
4. Do you think the pumps have enough capacity for this application? Yes, pumps turn off or run at less than full speed.
5. Which scenario had the lowest energy costs? Which do you think would have the lowest life-cycle cost? Tank had lowest energy cost, while variable speed will probably have lowest life-cycle cost. Must compare VFD costs with tank costs and benefits.
6. Why was the energy use for the no tank constant head scenario the greatest? What did the other two scenarios do to lower costs? Constant speed pump cannot turn off if there is no storage or slow down if there is no variable speed drive.
7. What was the range of relative speeds for the variable speed pump? If the target head were to increase, how do you think the speed would change? 0.87 to 0.92, speed would increase if target head increased.
Variable-Speed Pumping and Energy Costing Analysis Copyright © December-2008 Bentley Systems Incorporated
35
Water Quality Modeling
Page 8-1
Fundamentals of Water Quality Modeling Simulate movement and transformation of constituents in the distribution system
Foundation of Water Quality Modeling
Representation of Physical, chemical, and biological processes to simulate movement and transformation of the components in the distribution system
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-2
Why Model Water Quality? • SDWA requires compliance at the tap; not just at treatment plant • Water movement - quite complex and nonintuitive • Water quality of sources may differ • Sampling provides a limited picture of water quality throughout the system • Test alternative plans to reduce water quality deterioration
Distribution System Water Quality Issues • Covering tanks
• Taste & odor complaints
• Cross connection control
• High turbidity
• Lead and copper rule • Disinfection decay • DBP formation • Flushing
• Disinfection of new mains and tanks • Disinfection during and after breaks • Contaminated sources • Litigation
WQ modeling has been useful in many of these areas
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-3
Design Applications • Checking impacts of new tank • Adding disinfection booster station • Interconnecting two service areas • Extending distribution system • Adding new services • Impact of pipe sizing • Pipe cleaning and lining • Pipe layout (eliminating dead ends)
Operation Applications • Adjusting disinfectant feeds • Selecting disinfectant – chlorine, chloramines
• Balancing sources • Understanding complaints • Adjusting PRVs and pump controls
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-4
Water Quality Modeling History • 1930’s-present: Hydraulic modeling • 1960’s-1970’s: Pollution awareness (Love Canal, EPA) • 1980’s: First steady-state & dynamic WQ models • 1991: EPA-AwwaRF Water Quality Modeling Workshop • 1990’s: WQ legal cases - Woburn (A Civil Action) etc. • 1993: Introduction of EPANET • Mid 1990’s: Chlorine modeling research • Mid 1990’s: Introduction of powerful user friendly models • Mid to late 1990’s: Modeling of water quality in tanks
Water Quality in Distribution Systems • Affected by: – – – –
source water operation of system transport and transformations storage
• Significant variations in water quality – temporally – spatially
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-5
Hydraulic and Water Quality Modeling • Modern distribution system models actually two models • Hydraulic model calculates flows and velocities – used as input by a water quality model
HYDRAULIC MODEL
WATER QUALITY MODEL • water quality results
• flows and velocities
Water Quality Simulation Flow Chart Data Entry Initial Hydraulic Conditions Solve EPS Hydraulics Last Time Step?
NO
YES
Initial Water Quality Conditions Solve Water Quality Equations Last Time Step?
NO
YES
Results
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-6
Water Quality Modeling Processes
• Hydraulics • Transport • Bulk reactions • Wall reactions • Tank hydrodynamics
Processes Affecting Water Quality Tanks
Reservoirs Leak
Treated Transformations in Drinking the bulk water Water Transformations at or near the wall
TAP
Cross Connections
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-7
Types of Modeling of Quality of Water
• Tracking of source • Age of the • Water Components
Source Tracing • With multiple sources of water, model can trace movement from a source over time • Multiple runs to trace all sources • No calibration (beyond hydraulic calibration) can be done 100 % of water from Source A 0
time
100 % of water from Source B 0
Copyright © 2008 Bentley Systems Incorporated
time
Dec-08
Water Quality Modeling
Page 8-8
Water Age • Calculate age of water at each node over time • Age influenced by residence times in tanks and reservoirs • Age highest in dead ends or long pipes with little flow • No calibration (beyond hydraulic calibration) can be done • Consider tank initial condition
Constituents • Conservative substances: Concentration of conservative substances only change due to mixing • Non-conservative substances: Concentration of non-conservative substances change (grow or decay) – Chemical, Biological & physical processes – Represented by different mathematical transformations
• Typical constituents that are modeled – Chlorine & chloramines – DBPs (Trihalomethanes) – Fluoride (as a tracer)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-9
Constituents • Salinity (TDS)
• pH/alkalinity
• Nitrates/Nitrites
• hardness
• Metals
• Lead & copper
• Chlorine
• Fluoride
• Chloramines
• Solids/turbidity
• Organics
• Microbial activity
• VOC’s
• Taste & odor
• DBP’s (THM)
First Order Decay • Constituent decays proportionally to concentration • .dC
/ dt = kC
• Exponential decay: C t = C 0 e
− kt
– Co is initial concentration; t is time – k is decay coefficient (usually expressed per day)
• Chlorine residual usually follows 1st order decay • Half-life: Time to decay to 50% of initial concentration
C0 Example: k = 0.5/day Half-life = 1.4 days
Concentration
Co/2 Half-life
Copyright © 2008 Bentley Systems Incorporated
Time
Dec-08
Water Quality Modeling
Page 8-10
Zero-Order Growth or Decay • Constituent grows (or decays) at a constant absolute rate • .dC / dt • .C t
=k
= C 0 + (rΔt )
– C0 is initial concentration – Δt is time step – r is growth rate
• Age is an example of zero order growth (r = 1)
Concentration or Age
C0 time
First-Order Growth to Equilibrium • Constituent grows proportionally to concentration to an equilibrium value • .dC / dt = k (C max − C ) • Constituent exponentially approaches a maximum value
(
• .C t = C max − C max − C 0e − kt
)
– C0 = initial concentration, Cmax = max. concentration
• Trihalomethanes are an example
Concentration
Cmax C0 time
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-11
Problem Definition • Given: – – – – –
Network representation Flows in all pipes (from hydraulic model) Reaction rates Source concentrations Initial conditions
• Determine: Concentration at all nodes at all time periods
Nodal Conservation of Mass - Complete Mixing Total mass in = Total mass out
Q1, C1
Q3, Cout Node
Q4, Cout
Q2, C2
C out = [(Q1C 1) + (Q 2C 2 )] / (Q1 + Q 2 )
Q1 + Q 2 = Q 3 + Q 4 Is there complete mixing at a junction ? Sandia
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-12
Example of Nodal Calculations 2 gpm 1.67 mg/L
10 gpm 1 mg/L Node
28 gpm 1.67 mg/L
20 gpm 2 mg/L
Qin = QOUT = 30 gpm C out = [(10 gpm × 1mg / L) + (20 gpm × 2mg / L)] / (10 gpm + 20 gpm ) = 1.67 mg/L
Tank Nodes • Tanks different from junction nodes because of storage • Water quality changes due to – inflow quality – transformations in tank
• Most models assume that tank is instantaneously and completely mixed (more on this later)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-13
Model Elements • Pipes – Flow and velocity can change over time – Water ages as it moves through a pipe – Quality can change due to transformations
• Pumps and Valves – No quality transformations – No detention time
Transport in Pipes • Advection only – in direction of flow
C
• No longitudinal dispersion – plume does not spread out – except for inadvertent numerical dispersion
x
• Complete lateral mixing
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-14
Additional Data Needs for Water Quality Model • Source concentrations • Initial concentrations – most important for tanks
• Reaction rates • Tank mixing model • Chemical feed rates • Water quality tolerance • Diffusivity – depends on constituent
Initial Conditions Concentration
Tank with well-defined initial conditions
Typical node
Tank with poorly-defined initial conditions
0
Time
Model input: Conditions at time = 0
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-15
Chlorine Modeling • Most common WQ modeling task • Predict the chlorine residual throughout the distribution system • Can vary significantly during the day
Chlorine Reactions in a Pipe
Boundary Layer BULK FLUID
Boundary Layer WALL
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-16
Bulk Decay • Bulk decay: decay in flowing water • Usually represented as first order decay
C t = C 0e − kt
• Decay rate
– depends on water quality characteristics – independent of pipe material
• Use of negative sign when we refer to k – Implied when we talk about decay – Explicit when we talk about reaction rate
• Range of decay coefficients: 0.05 to 15 per day • Most typical range is 0.2 to 1.0 per day
Determination of Chlorine Bulk Decay Coefficient • Fill 8 to 12 bottles with source water and store in dark place at constant (water) temperature (e.g., water bath) • At intervals of a few hours and days, take a bottle and measure chlorine residual • Continue for normal max. water age in distribution system
Ln(Cl2)
K bulk = Ln(C1 / C 2 ) / (t1 − t 2 ) kbulk
Time in days
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-17
Bulk Decay Plots • Plot of log of chlorine vs. time does not always follow a perfect 1st order decay • Complicates modeling. Select representative value for bulk decay rate Ideal 1st order
Initial plateau
Piecewise linear
Time
Time
Ln(Cl2)
Time
Wall Decay • Wall decay: Interaction of water with wall • Due to corrosion, biofilm, and other processes at the wall • Depends on pipe material • Rate of loss of chlorine at wall depends upon – wall decay coefficient – rate bulk water contacts wall
• Generally not a factor in tanks & reservoirs – ratio of wall to volume is usually very small
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-18
Overall Decay Formulation First order reaction: C t = C 0 e − Kt Where:
K = kbulk +
k wall × k f
(
Rh k wall + k f
)
• Kf is mass transfer coefficient ; function of
– Reynolds number = momentum/viscous = vρD/μ – Schmidt no. = viscous/diffusion = μ/ρD
• Rh = hydraulic radius = Area/perimeter • viscosity (μ) ; density (ρ)
Determining Wall Coefficients • Difficult to determine wall decay coefficient – no direct measurement technique
• Estimate values in the field based on chlorine measurements under controlled conditions • Ideal experiment: – long isolated pipe with no connections – flow could be controlled – measure chlorine loss
• Typical range of values for kwall: 0 − 1 ft / day
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-19
Relationship between wall decay rate and pipe roughness? • Relationship seems logical: Rougher pipes have: – greater wall surface area – greater opportunity for biofilm growth
• .K wall = α /( Hazen Williams C - Factor) • Limited field data suggests a range of values for α of 0 to 100.
Water Quality Calibration • For conservative substances, source tracing and water age only hydraulic calibration • For chlorine modeling, field calibration is almost essential • Must identify water quality of sources • Apply good analytical methods
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-20
Analytical Methods • For source characterization or calibration • In-field or laboratory methods • Probes (conductivity, pH) • Continuous monitors (chlorine) • Grab samples • Laboratory analysis (GC-MS, AA) • Know precision & accuracy • Standard Methods
Example Chlorine Calibration Calibration is usually a trial and error process to match field data
Measured chlorine Kwall = 0. Kwall = 20 / C Kwall = 100 / C Kwall = 0.25
Chlorine Concentration (mg/L)
Time
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-21
Tracer Tests • Used to calibrate or validate EPS hydraulic model • Uses: – water quality model – conservative substance (tracer)
• Provides better hydraulic calibration that may be necessary to support WQ modeling • Very good for identifying closed valves
How to Do a Tracer Study PUMP
1. Inject tracer at a constant feed rate at entry to a zone over a period of many hours 2. Measure concentrations of tracer at key nodes ( ) at frequent intervals 3. Collect operational data required to run a model (pump, valve, tank operation). 4. Run model and compare predicted tracer concentrations to field data TANK
5. If predicted & observed do not agree, adjust hydraulic parameters to get better fit or check for data collection errors.
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-22
Chemical Feed • Concentration – of inflow, reservoir, etc. – .C = (C in Qin + QC ( feed )) / Qout • Mass inflow – mass feed, kg/s – .C = (C Q + QC ( feed )) / Q in in out • Flow paced booster – fixed concentration added (total inflow) – .C = C in + C (add ) • Set point – junction outflow fixed – C = C(setpoint) if Setpoint < Cin – else C = Cin
Impact of Storage on Water Quality • Tanks & reservoirs designed for hydraulic needs; water quality is secondary • Long residence times: – depress disinfectant residuals – promote bacterial growth
• Poor mixing can amplify water quality problems
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-23
To Minimize Water Quality Deterioration in Tanks • Water quality objectives: – Minimize water age and disinfectant loss – Achieve good mixing – Avoid stagnant zones
• Solution – Encourage good turnover – Increase velocity of inflow
Turbulent Jet Mixing: Primary Mixing Mechanism
PROFILE VIEW
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-24
Insuring Mixing During Fill Period
% Change in Volume During Fill
100 90 80 70 60 50 40 30 20 10 0
d = inlet diameter
Inlet Diameter (feet)
1
d=6’
2 3
d=4’ d=3’ d=2’ d=1’ 0
1
2
3
4
5
6
7
8
9
4 6
10
Volume (million gallons)
Stratified Conditions
Tin > T tank
Tin < T tank
Negatively Buoyant Jet
Copyright © 2008 Bentley Systems Incorporated
Positively Buoyant Jet
Dec-08
Water Quality Modeling
Page 8-25
Potential Mixing / Stratification Problems Top View
Side View
Top View
Tangential Inlets
Large Diameter Inlets
Complex Baffles
Side View
Ttank
Temperature Differences
Tinflow
Deflectors Standpipes
Tank Mixing Models Complete mix Plug flow (FIFO) Plug flow (LIFO) 2 compartment
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-26
Effects of Mixing Models
Calculated Concentration (mg/l)
2.0
Tank: T-1 Calculated Concentration versus Time
T-1\Cl-CM T-1\Cl-LIFO T-1\Cl-FIFO T-1\Cl-2C
1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0
16.0
32.0
48.0 Time (hr)
64.0
80.0
96.0
Other Uses for Water Quality Models • Determining historical exposures • Litigation • Recreating cross-connection events • Recreating complaints • Must rely on limited data
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Water Quality Modeling
Page 8-27
What’s Likely in the Future • Better models of water quality processes • More processes (pH, temperature, solids) • Integration of water quality models in system operation • Quality impacts of hydraulic transients & crossconnections • Greater confidence in water quality models
The End Water Quality Modeling Now Practical
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Dec-08
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Copyright © 2008 Bentley Systems Incorporated
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Workshop Overview In this workshop you will run through creating 6 different scenarios for Water Quality analysis. You will learn to set up a network scenario to investigate the blending of two sources, perform a water age analysis, a chlorine residual analysis (one with wall decay and the other without) and a trace analysis.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
WaterCAD/GEMS System Planning and Operation
WaterCAD/GEMS Extended Period Simulation
Workshop Objectives After completing this workshop, you will be able to:
Set up and perform a Water Age Analysis
Set up and perform a Trace Analysis
Set up and perform a Multisource Chlorine Mixing Analysis
Enter Constituents
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
1
Problem Statement
Problem Statement Runs 1-2 You are working with a system with two sources: one source (R-1) has low total dissolved solids (TDS) of 250 mg/L, while a second source (R-3) has a TDS of 600 mg/L. The low TDS source runs continuously, while the high TDS source only comes on when the water level in tank 1 drops to 163 ft. It goes off when the level reaches 168 ft. You want to investigate the blending of the two sources in the distribution system.
Runs 3-4 You are also concerned with the chlorine residual in the system. You will simulate 2 chlorine residual runs for the system, one considering wall decay and the other not considering wall decay and compare the results.
Runs 5-6 There have also been reports that the water in the system may be quite old, so you want to investigate the water age. In addition you would like to trace water from R1 to determine how much of the systems water is being generated by this reservoir. An EPS model of the system has already been constructed and is stored in a file named Water_Quality.wtg. You will use this model to analyze the water quality runs discussed above. Open this file from C:\Program Files\Bentley\WaterDistribution\Starter to begin the workshop.
2
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 1- TDS Simulation
Run 1- TDS Simulation WaterGEMS has a default water quality alternative called Default -Constituent which already exists. You will create an additional alternative to model TDS. Any substance can be modeled provided you enter the correct data to describe its concentration and decay. Exercise: Creating the TDS Alternative Setup an alternative for TDS by opening the Alternatives Manager. 1. Expand the Constituent Alternative category and add a child alternative to Default-Constituent. 2. Rename it to TDS.
Next, you will need to define TDS as a constituent. Exercise: Creating the TDS Constituent 1. Open the TDS Alternative.
2. Click the ellipsis (…) to open the Constituents dialog. 3. Click on New
and create a new constituent label named TDS.
4. Click on the TDS label and confirm that a Diffusivity value of 1.300e-008 ft2/s is entered and the box for Unlimited Concentration? is checked.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
3
Run 1- TDS Simulation
Note: Since TDS is a conservative constituent, the reaction rate (bulk and wall decay) coefficients are zero. 5. Click Close and you should be back at the constituent alternative screen. 6. Select TDS from the dropdown menu for Constituent.
7. You will need to set the concentration of TDS in the two reservoirs based on the table below. Reservoir
TDS -Concentration (Initial) (mg/L)
R-1
250
R-3
600
8. Select the Reservoir tab on the Constituent dialog to enter the above concentrations:
4
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 1- TDS Simulation
Note: The initial TDS concentration in T-1, T-2, and the junctions are zero so you will not need to modify these. 9. Click Close to accept the data. Exercise: Entering the calculation option for analyzing TDS 1. Now set up a calculation option for analyzing TDS concentrations with the name Constituent Analysis – 144 hours.
2. Edit the new Calculation Option and set the following: Calculation Type
Constituent
Base Date
Today’s Date
Start Time
12:00:00 AM
Duration (hours)
144
Hydraulic Time Step (hours) 1.0
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
5
Run 1- TDS Simulation
3. Close the Calculation Options dialog. Exercise: Creating the TDS Scenario 1. Open the Scenarios manager. 2. Create a child scenario from the Base. 3. Name it TDS.
4. Review the properties of TDS and set the Demand Alternative to Peak Hour and the Constituent Alternative to TDS. 5. The Calculation Option should be Constituent Analysis – 144 hours.
6
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 1- TDS Simulation
6. Close the Scenarios manager. Exercise: Computing the TDS scenario and reviewing results 1. Make TDS the active Scenario. 2. Select Compute from the menu bar. 3. Review the Calculation Summary (all time step buttons should be green) and then close the Calculation Summary. Exercise: Using color coding to review the TDS To view the results graphically set up pipe color-coding for TDS using the color range table below: Value Element Symbology if the window is not already open. 2. Right click on Pipe and select New > Color Coding to create a color-coding table. 3. Select Concentration (Calculated) for the Field Name. 4. Click the Calculate Range button to see the Minimum and Maximum values. 5. Make sure Options: is set to Color. 6. Enter the information from the above table.
7. When finished, click Apply and then OK. Exercise: Using the EPS Results Browser to scroll through the time steps The EPS Results Browser will be used to scroll though the TDS Scenario time steps. 1. Click the EPS Results Browser
button or select Analysis > EPS Results Browser.
2. Size and drag the EPS Results Browser window to a convenient location on your screen. 3. Set the Increment to 1.0 hour and use the Step button to scroll through several time steps and see how TDS levels fluctuate by observing link color changes. Note: It should be obvious when the pump starts and stops. 4. Click the Play
8
button to automatically scroll through the time steps.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 1- TDS Simulation
5. Use the Speed slider to increase or decrease the scroll rate.
Exercise: Graphing calculated concentration at J-13 Make a graph of calculated concentration at Junction J-13. 1. Select View > Graphs. 2. On the Graphs window select New > Line-Series Graph using the drop down arrow next to the New button. 3. Select node J-13 from the drawing and click on Done. 4. On the Graph Series Options window, the TDS scenario should be checked and Elements should be J-13. 5. In the Fields section, expand Results (Water Quality) and check the box for Concentration (Calculated). 6. Clear the check marks for the other Fields.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
9
Run 1- TDS Simulation
7. Click OK. You should see the graph below:
Note: You can enhance the appearance of your graph if you would like to. 8. Click the Data tab to view the data that was used to create the graph. 10
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 1- TDS Simulation
Note: You can sort and filter the information shown under the Data tab. 9. To access the Filter option, right click on the column header for Time and select Filter > Custom…. 10. You can apply a filter to show only the last 24 hours of any run and then sort the TDS column in ascending and descending order to get the minimum and maximum values. 11. Close the Data table and rename your graph TDS.
12. Open the graph again and use the graphs and tables to fill in the Results Table and answer the questions for Run 1. 13. Save your file.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
11
Run 2- TDS-300 Simulation
Run 2- TDS-300 Simulation In the second run you will set more realistic initial conditions and run the simulation for a longer time period. Results from the first Scenario run can be used to generate a graph of TDS concentration over time for the two tanks and use the graph to estimate starting initial concentrations. Hint: Notice that in T-1 and T-2 the concentration was still climbing at the end of the 144-hour run. Tank T-1 has a concentration of 255 mg/l and climbing and T-2 has a concentration of 256 mg/l and climbing. Based on these graphs, we decide to modify our initial conditions for Run 2. A good starting condition for both T-1 and T-2 is 300 mg/l for Run 2. For this run you will need to create a new TDS alternative and enter more accurate starting conditions (300 mg/l) for T-1 and T-2. Then set-up a second scenario for this updated TDS alternative. Exercise: Creating the TDS-300 Scenario 1. Open the Alternatives manager and create a child alternative from TDS. 2. Name it TDS-300.
3. Open TDS-300, click on the Tank tab, and enter 300 mg/L in Concentration (Initial) for each tank.
4. Click Close and close out of the Alternatives manager.
12
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 2- TDS-300 Simulation
Exercise: Setting the 288 hour calculation option 1. Open the Calculation Options window (Analysis > Calculation Options) and duplicate the Constituent Analysis – 144 hours. 2. Rename the new calculation option Constituent Analysis – 288 hours and change its Duration (hours) to 288. 3. Close the Calculation Options dialog. Exercise: Creating the TDS-300 Scenario 1. Open the Scenarios manager and create a child scenario from TDS. 2. Rename the new scenario TDS-300.
3. Edit the scenario and change the Constituent Alternative used by this scenario to be TDS-300, and change the Calculation Option to Constituent Analysis – 288 hours.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
13
Run 2- TDS-300 Simulation
4. Close the Scenarios manager. 5. Set TDS-300 as the active scenario on the main screen. 6. Select Compute from the menu bar to calculate the scenario. 7. Close the Calculation Summary. 8. Fill in the column for Run 2 using graphs and other viewing tools. Note: Remember to look at the last 24 hours.
14
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 3- Chlorine Residual
Run 3- Chlorine Residual In the next 2 runs you will simulate the resulting chlorine residual throughout the system. To begin you need to add chlorine as a constituent. Exercise: Creating the chlorine constituent and alternative 1. Open the Alternatives manager and create another child from the DefaultConstituent Alternative called Chlorine.
2. Open the Chlorine Alternative. 3. Select the ellipses button for the Constituent field to add Chlorine as a constituent. 4. Select New to create a new constituent and name it Chlorine. 5. The Diffusivity is 1.300e-008 ft2/s. Note: Chlorine reaction is a first order reaction. 6. From a bottle test of decay you know that the Bulk Reaction Rate is –0.3 (mg/L)^(1-n)/day. Note: Do not worry about entering wall reaction.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
15
Run 3- Chlorine Residual
7. Select Close to bring you back to the Constituent screen. 8. Select Chlorine for the Constituent.
9. Enter a Concentration (Initial) of 1.0 mg/L for R-1 and R-3 on the Reservoir tab.
10. Close the Constituent Alternative. Exercise: Creating, computing and reviewing the chlorine scenario 1. Open the Scenarios manager. 16
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 3- Chlorine Residual
2. Add a child to the Base scenario and name the new scenario Chlorine Residual.
3. Make sure that the Demand Alternative is Peak Hour, the Constituent Alternative is Chlorine, and the Calculation Option is Constituent Analysis – 144 hours.
4. Close the Scenarios manager. 5. Confirm that the active scenario on the main window is Chlorine Residual. 6. Select Compute to run the scenario. 7. Fill in the results column for Run 3 using graphs and other viewing tools.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
17
Run 4- Chlorine Residual with Wall Reaction
Run 4- Chlorine Residual with Wall Reaction For the next chlorine residual run we will make a modification to the wall reaction. Your supervisor has noticed that the observed chlorine residual in the network is generally lower than modeled results and she suspects there is a significant wall demand. In order to more accurately model the real world situation we need to enter a wall reaction rate for Chlorine. Exercise: Creating the chlorine plus wall reaction alternative 1. Open the Alternatives manager and create a child alternative to the Chlorine Constituent Alternative. 2. Name it Chlorine + Wall.
3. Open Chlorine + Wall and click on the ellipsis (…) to enter the wall reaction coefficient. 4. Click on Chlorine and then click Duplicate
.
5. Rename the new label Chlorine + Wall. Note: The Diffusivity and Bulk Reaction Rate fields should already be filled in. 6. Select First Order for Wall Reaction Order and enter -1 ft/day as the value.
18
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 4- Chlorine Residual with Wall Reaction
7. Click Close. 8. Select Chlorine + Wall as the Constituent, and then click Close. Exercise: Creating the chlorine residual scenario 1. Go to the Scenarios manager and create a child scenario from Chlorine Residual. 2. Name the new scenario Chlorine with Wall.
3. Edit the scenario and select Chlorine + Wall as the Constituent Alternative. 4. You want to analyze over a longer duration, so set the Calculation Option to Constituent Analysis – 288 hours.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
19
Run 4- Chlorine Residual with Wall Reaction
5. Close Scenarios manager and make sure that Chlorine with Wall is the active scenario on the main screen. 6. Select Compute to calculate the scenario. 7. Fill in the results column for Run 4 using tables and graphs.
20
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 5- Age
Run 5- Age In the fifth run you will investigate water age in the system. Exercise: Creating the age alternative 1. Go to the Alternatives manager and expand the Age category. You will notice that a Default-Age Alternative already exists. 2. Add a child to Default-Age and name it Age. 3. Open the new alternative. 4. Set the Age (Initial) (hours) in J-1 through J-19 to 1 hour, the water age in the Reservoirs to 0.00 hours and the initial age in both tanks to 72 hours (3 days). This is a typical water age found in many tanks.
5. After you have entered these values, select Close. Exercise: Creating new age calculation options 1. Go to Calculation Options (Analysis > Calculation Options). 2. Create a new calculation option called Age-144 that has the following: Calculation Type
Age
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
21
Run 5- Age
Start Time
12:00:00 AM
Duration (hours)
144
Hydraulic Time Step (hours) 1.0 3. While you are here, create another Calculation Option named Age-288 with the same parameters, but with a Duration of 288 hours.
4. Save your file. Exercise: Creating the new Age scenarios 1. Open the Scenarios manager and create a new child scenario from the Base scenario. 2. Name the new scenario Age-144. 3. Open the scenario and select Age as the Age Alternative and Age-144 as the Calculation Option. 4. Close the Scenarios manager. Exercise: Computing and reviewing the Age scenario 1. Make Age-144 the active scenario and Compute it. 2. Use a graph to review the water age in the two tanks over the 144 hours. 3. Have both tanks reached an equilibrium condition? 4. If not, then run the age scenario for a longer duration (try 288 hours) in order to select better starting ages for the tanks and make another run. 5. Once you feel the starting conditions for age are correct, complete the results column and answer the questions for Run 5 in the results table. Note: The answers at the end of the workshop are based on T-1 initial age = 72 hours, T-2 initial age = 144 hours, and an analysis duration of 288 hours).
22
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 6- Trace
Run 6- Trace In the sixth run you will do a source tracing for reservoir R-1. This will tell you the amount of water at each node that comes from this reservoir. You know from historical analysis that on average about 80% of the water comes from reservoir R-1, so as a starting point, you will set the initial trace percentage to 80% for all junctions and tanks. Set the initial trace percentage to zero for R-1 and R3. Exercise: Creating the trace alternative 1. Open the Alternatives manager and expand the Trace Alternative category. 2. Create a child alternative to Default-Trace and name it Trace.
3. Open the Trace Alternative and set the Trace Element to R-1 by picking the ellipsis […] and then selecting R-1 from the drawing.
4. Select the Junction tab and globally change all Trace (Initial) (%) to 80%. 5. Select the Tank tab and set both tanks at 80%. 6. Click Close when done. Exercise: Setting up the trace calculation options 1. Open the Calculation Options window (Analysis > Calculation Options). 2. Create a calculation option and name it Trace-450.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
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Run 6- Trace
3. Set the following: Calculation Type
Trace
Start Time
12:00:00 AM
Duration (hours)
450
Hydraulic Time Step (hours) 1.0
Exercise: Creating and computing the trace scenario 1. Now open the Scenarios manager and create another child from the Base scenario. 2. Name this scenario Trace.
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Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Run 6- Trace
3. In the Scenario Properties set Trace as the Trace Alternative and Trace-450 as the Calculation Option.
4. Close the Scenarios manager. 5. On the main window, make sure that Trace is the active scenario. 6. Run the trace analysis by selecting Compute. 7. Complete the results column and answer the questions for Run 6 in the results table.
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
25
Results Table
Results Table Choose the minimum and maximum values by looking at the last 24 hours of each simulation. Node
26
Condition
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Constituent
TDS (mg/L)
TDS (mg/L)
Chlorine Residual (mg/L)
Chlorine Residual w/wall (mg/L)
Age (hours)
Trace R1
Initial values at T-1
0
Initial values at T-2
0
J-13
Min Value
J-13
Max Value
J-3
Min Value
J-3
Max Value
T-1
Min Value
T-1
Max Value
T-2
Min Value
T-2
Max Value
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. Why were initial conditions at the tanks maintained so long in comparison with those at the nodes?
2. How long did it take to reach the equilibrium pattern of TDS at nodes: J-13 J-3 T-1 T-2
3. What is the maximum water age at the two tanks (T1 and T2)? What type of problems could result in tanks with water that is this old?
4. What part of the distribution system showed the greatest and least temporal variation in source water tracing?
5. If you were deciding where to live in town based on water supply, which area would you choose and why?
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
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Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers Node
28
Condition
Run 1
Run 2
Run 3
Run 4
Run 5
Run 6
Constituent
TDS (mg/L)
TDS (mg/L)
Chlorine Residual (mg/L)
Chlorine Residual w/wall (mg/L)
Age (hours)
Trace R1
Initial values at T-1
0
300
0
0
72
80%
Initial Values at T-2
0
300
0
0
144
80%
J-13
Min Value
250
250
1
0.8
0.8
47%
J-13
Max Value
436
436
1
0.9
1.4
100%
J-3
Min Value
241
260
0.6
0.4
1.2
59%
J-3
Max Value
395
395
1.0
0.8
64
97%
T-1
Min Value
238
297
0.4
0.3
75
85%
T-1
Max Value
255
300
0.5
0.4
84
86%
T-2
Min Value
233
369
0.3
0.2
138
63%
T-2
Max Value
256
372
0.3
0.2
146
63%
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
1. Why were initial conditions at the tanks maintained so long in comparison with those at the nodes? There is a much greater volume in the tanks than in pipes to flush out the initial conditions.
2. How long did it take to reach the equilibrium pattern of TDS at nodes: J-13
10 hours
J-3
10 hours
T-1
250 hours
T-2
300 hours
3. What is the maximum water age at the two tanks (T1 and T2)? What type of problems could result in tanks with water that is this old? Maximum age in Tank T-1 is 3 days and the maximum age in Tank T-2 is 5 days. Especially in water as old as 5 days, you can lose your chlorine residual and bacterial re-growth can occur.
4. What part of the distribution system showed the greatest and least temporal variation in source water tracing? The area near reservoir R-1 showed the least temporal variation while the area near reservoir R-3 showed the most variation. This behavior is because R-1 is always being used as a source and R-3 is intermittent.
5. If you were deciding where to live in town based on water supply, which area would you choose and why? In the area served directly by Reservoir R-1 (near nodes J-1, J-14, J-12, etc.) because it is always served by a single source, the water is very young, the TDS is lower, and the pressure is reasonable (60 psi).
Multisource Mixing, Chlorine Residual, Age and Trace Analysis Copyright © December-2008 Bentley Systems Incorporated
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Criticality Analysis
Page 9-1
Criticality Analysis Quickly finding the weak links
Criticality • Need to identify critical elements • Can not do it by simply removing pipe links • Real outages depend on valving
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Criticality Analysis
Page 9-2
Reliability Example
12” 6” 12”
X
6” 16”
= Valve
Segmentation and Criticality • Segment – smallest isolatable set of elements • Segmentation – identifying segments • Criticality – determining the critical segments • Isolation valves – special elements to help define segments
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Dec-08
Criticality Analysis
Page 9-3
Valving • How many valves are enough? • Valves minimize impact of outages • Valves improve system reliability • # of valves often done by rule of thumb • Standards – 10 State • < 500 ft commercial districts • < 800 ft residential
– California • < 1000 ft for < 12 in.
Valving Approaches
N valves at cross
N valves at T
Copyright © 2008 Bentley Systems Incorporated
N-1 valves at cross
N-1 valves at T
Dec-08
Criticality Analysis
Page 9-4
Isolating Valve Elements • Usually gate or butterfly valve • Can also be control valves • Not hydraulic model nodes • Do not affect model size • Must reference the pipe they are on • Can import from GIS
Isolating valve not on pipe, but within tolerance
Should we move valve to pipe?
Or modify pipe to pass through valve?
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Dec-08
Criticality Analysis
Page 9-5
Valve referenced to pipe
Analysis Steps • Existing model • Place isolating valves • Identify distribution segments • Identify outage segments • Assess criticality of segments – Connectivity – Hydraulics
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Dec-08
Criticality Analysis
Page 9-6
Distribution Segments • Smallest portion of system isolated by valves • May be – Part of a pipe – One or more pipes plus junctions
• Not consistent with model topology
J-1
P-1
V-21
S-101
V-22
J-2
S-103
S-102
P-12
P-15
P-11 P-14
P-9
P-8
P-7 P-10
P-6
P-13 P-16
P-2
P-5
P-4
P-3
P-1
P-17
Segmentation Process
Build model system without valves
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Dec-08
Criticality Analysis
Page 9-7
P-5
P-2
V-2 V-1
P-4
V-7
V-12
V-10 V-11
V-16 P-12 V-18
P-11
V-13
V-15 V-14
P-13
V-19
V-17
P-15
P-14
V-9
P-16
P-10
P-6
P-9
V-5
V-3
P-7
V-4
V-8
V-6 P-3
P-8
P-1
P-17
Segmentation Process
V-20
Overlay valves onto model
Segmentation Process V-2 V-1 V-4
S-1
V-8
V-6
V-3
S-4
S-3
S-2
V-5
V-7
V-9
V-10 V-11
S-6
S-5
S-7
V-12
V-16 S-9
V-13
S-8
V-15
V-14
V-17
V-18 V-19 V-20
WaterCAD/GEMS represents segments by a single color each
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Dec-08
Criticality Analysis
Page 9-8
Segmentation Process V-2 V-8 V-1
V-3
S-1
V-9
S-2 S-3
V-5
S-4
V-10
V-6
V-4
V-7
V-16
V-12 V-13
V-11
S-6
S-5
V-15 S-8
S-9
V-18
V-19
V-20
V-17
V-14
S-7
Segment topology (segments are circles; valves are lines)
Segment properties Segments
Valves to isolate segment
Pipes in segment
1
V-1 2 3 4
P-1 2 3 7
2
V-3 5
P-3
3
V-7 9
P-4
4
V-8 9 10 11
P-4 6 9 17
5
V-4 12
P-7
6
V-5 6 7 16
P-3 4 5 8
7
V-11 18 19 20
P-9 12 13 16
8
V-12 13 14 15
P-7 10 11 14
9
V-15 16 17 18
P-8 11 12 15
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Criticality Analysis
Page 9-9
Segmentation Results • Large segments – likely to break, more customers out of service • Segments with many valves – very difficult to shut down • Large volume segments – difficult to drain • For each segment: – Shortfall = Demand-Demand Met – % Shortfall = Shortfall/Demand
Segmentation Results
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Dec-08
Criticality Analysis
Page 9-10
Outage Segments • Outage segments – segments downstream of current segment • Rare in looped systems • Pervasive in tree systems • Sometimes there are surprises • There can be large outage segments even in looped systems • Calculating outage segments separate step
System with isolating valves
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Dec-08
Criticality Analysis
Page 9-11
Color coded segments
Outage segment identified
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Dec-08
Criticality Analysis
Page 9-12
Criticality Cases • Node isolated from source • Negligible impact • Service reduced
Criticality Options • Type of run – Connectivity only – Steady hydraulic – EPS hydraulic
• Handling demands in hydraulic runs – Pressure dependent demand – No PDD
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Dec-08
Criticality Analysis
Page 9-13
Pressure Dependent Demand (PDD) • Water leaves system through orifices • Flow from orifices depends on pressure • Many demands are volume driven • Demand mix of – Pressure dependent – Pressure independent
Demands • Volume Based – – – – –
Toilet flushing Washing machines/dishwashers Bath tub Industrial process tanks Cooling water makeup
• Pressure based – Sprinklers – Leaks
• Most demands fall somewhere in between
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Dec-08
Criticality Analysis
Page 9-14
Traditional PDD • Use flow emitter • Orifice equation:
Q = k Pn • Adequate for some applications • Inflexible • Poor behavior for negative P
Pressure Dependent Demands 2.5
2
Q, gpm
1.5
1
0.5
0 0
20
40
60
80
P, psi
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Dec-08
Criticality Analysis
Page 9-15
WaterGEMS v8 PDD • Need more flexibility than emitters • Use cases – Outages – Pressure reduction for leakage – Systems w/limited capacity
• Determine shortfall or leak reduction • Criticality analysis
Data for PDD • Existing model • PDD function Q = f ( P ) – Power – Piecewise linear
• Reference and threshold pressure • % volume based • Junctions with PDD
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Criticality Analysis
Page 9-16
Power PDD Curve 35 30
Flow, gpm
25 20 15 10 5 0 0
20
40
60
80
100
Pressure, psi
Reference Pressure - Demand 35 30
Flow, gpm
25 20 15 10 5 0 0
20
40
60
80
100
Pressure, psi
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Dec-08
Criticality Analysis
Page 9-17
Threshold Pressure 25
Flow, gpm
20 15 10 5 0 0
20
40
60
80
100
Pressure, psi
Combining Fixed and Pressure Dependent Demand 15
Flow, gpm
PDD Fixed
10
Total
5
0 0
20
40
60
80
100
Pressure, psi
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Dec-08
Criticality Analysis
Page 9-18
Running PDD 1. Define PDD function 2. Set up PDD alternative 3. Specify local overrides 4. Set up calculation options for PDD 5. Compute
Using Criticality 1. Create model w/isolating valves 2. Set up scenarios (steady, PDD, etc.) 3. Start criticality 4. Create segments 5. View isolating segments 6. Determine criticality
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Dec-08
Criticality Analysis
Page 9-19
The End A chain is only as strong as its weakest link.
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Copyright © 2008 Bentley Systems Incorporated
Analysis of Valving and Critical Segments Workshop Overview In this workshop you will become familiar with an existing system and the isolating valves that it already contains. Using the WaterGEMS Criticality tool you will identify segments in the system and determine if there are any outage segments. You will also identify problem areas in the system and the criticality of the identified segments.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
WaterCAD/GEMS System Planning and Operation
Workshop Objectives After completing this workshop, you will be able to:
Identify Criticality Segments in a model
Identify Outage Segments in a model
Use isolation valves
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
1
Problem Statement
Problem Statement In this workshop, you will start with a pipe network model that already contains isolating valves. You will use the information about the valves to create distribution system segments. You will identify problem areas in the system using the information about segments and view the segments in the drawing. You will then find if there are any outage segments. Next you will quantify the criticality of the segments. You will then identify some pipes and valves that may be inserted into the system to improve the performance of the system. The pipe network you are starting with is shown below. The source is in the southwest corner of the drawing.
2
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Getting Started
Getting Started This section just walks you through the existing model so that you are familiar with it for the rest of the workshop steps. Exercise: Opening the starter file 1. Open WaterCAD V8i or WaterGEMS V8i. 2. On the Welcome screen, select Open Existing Project or select File > Open and navigate to C:\Program Files\Bentley\WaterDistribution\Starter. 3. Open the Criticality.wtg file. Note: The drawing shown in the Problem Statement will open. Exercise: Familiarizing yourself with the system 1. Click on the Properties the Properties dialog.
button and type R-1 into the search box at the top of
2. Click the Zoom In button from the main toolbar and it will automatically zoom to that element which is the source for this system.
3. Use the Pan button or hold down the scroll wheel and follow the pipes back through the system. 4. You may want to zoom out by rolling the scroll wheel or using the Zoom Out button. 5. Select the scenario called Original Valves from the scenario dropdown menu. 6. Zoom into any intersection and look at the isolating valve elements which are labeled ISO-number. 7. Double click on one of the isolating valve elements so that the Properties window will open. Note: Each isolating valve has a Reference Pipe which is the pipe on which the valve is located. The pipe stays associated with the valve even if the valve element symbol is moved off the pipe.
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
3
Criticality and Segmentation
Criticality and Segmentation Now that you have gotten a feel for isolating valves we are going to move onto the Criticality Manager. Exercise: Creating a criticality study 1. Open the Criticality manager by selecting Analysis > Criticality or by clicking the Criticality button. This will open an empty Criticality dialog.
2. Click New to create a criticality study. 3. On the Add Scenario dialog select Original Valves as the scenario.
4. Click OK. 5. On the Segmentation Scope tab, select Entire Network from the dropdown menu.
4
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
6. Click the Compute
button to start the segment identification.
Note: If the following screen comes up click Yes.
When complete, a list of segments should be displayed as shown below:
The table shows the number of segments and gives some statistics about the segments.
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
5
Criticality and Segmentation
Exercise: Viewing segments with color coding 1. Color code the drawing by segment, by clicking on the Highlight Segments button at the top of the middle pane in the Criticality manager. 2. Drag the Criticality manager away from the top of the drawing and view the segments. Note: The black and white drawing below does not do justice to the drawing.
3. Find which segment requires the largest number of valves to isolate a segment by right clicking on the Isolation Elements column heading and selecting Sort > Sort Descending. Note: This will give you the segment with the most valves.
6
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
4. Click on that segment in the Label column and only that segment will appear as shown below:
5. Click the Zoom To Segments button at the top of the middle pane and this will zoom the drawing to that segment.
6. Fill in the appropriate results at the end of this problem. Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
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Criticality and Segmentation
Exercise: Finding Outage Segments 1. In the left pane of the Criticality manager, click on Outage Segments and click Compute. 2. In the right pane, right click on the Outage Set Length column heading and select Sort > Sort Descending.
3. Select the largest outage segment based on Outage Set Length and highlight it in the Label pane. 4. Click the Highlight Segment
button on top of the Label pane.
5. Move the Criticality manager aside and look at the drawing.
8
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
Note: This shows the somewhat trivial results in which when the segment from the source fails, the entire system is without water. 6. Repeat these steps for the second and third largest outage segments. These are interesting in that they show locations where a single outage can put a large number of customers out of service and a single isolation valve can greatly reduce the outage segment size. Exercise: Determining Criticality 1. Click on Criticality in the left pane of the Criticality manager. 2. In the right pane, check the box marked Run Hydraulic Engine. 3. Click Compute above the left pane.
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
9
Criticality and Segmentation
You should get the results below:
4. Sort the segments in the System Demand Shortfall (%) column in the right pane in Descending order. 5. Review the shortfalls due to outages of various segments. 6. Fill in the appropriate results at the end of the problem. 7. Close out of the Criticality dialog when finished.
Improving the System You will now install a pipe, with valves at each end, connecting nodes J-44 and J-45 in an attempt to improve the system. Exercise: Setting up the new improved system 1. Create a new active topology alternative, called New Interconnect, which will be a child of W-Valves.
2. Create a new scenario called Improved System, which will be a child of Original Valves. 10
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
3. Edit the Improved System Scenario and using the dropdown menu for Active Topology select New Interconnect as the alternative.
4. Switch to the Improved System scenario. 5. Zoom to the portion of the drawing where node J-44 is located. 6. Select the Pipe Layout click and select Done. 7. Select the Isolating Valve new pipe.
tool and draw a new pipe between J-44 and J-45, right tool and place isolating valves at each end of the
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
11
Criticality and Segmentation
Note: Do not worry if the element labels for the valves are different from above. 8. Double click on each isolating valve to insure that it is referenced to the correct pipe.
Criticality of Improved System Exercise: Viewing the criticality of the Improved System Scenario 1. Select Analysis > Criticality. 2. In the left pane, highlight Criticality Studies and click the New button. 3. Select the Improved System from the Add Scenario dialog. 12
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
4. Click OK. 5. Select Improved System in the left pane and switch to the Segmentation Scope tab in the right pane. 6. From the Scope Type pull down menu, select Entire Network. 7. Click the Compute button above the left pane. 8. Review the results under the Segmentation Results tab in the right pane. 9. Highlight Outage Segments under Improved System and click Compute. 10. In the right pane, right click on Outage Set Length and select Sort > Sort Descending.
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
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Criticality and Segmentation
Note: Note the length of the second longest segment. 11. Fill in the Results Table. Note: Notice how that single pipe greatly improved the impact of a shutdown. 12. View the second longest outage segment by selecting Outage Segment – 46 from the middle pane and clicking the Highlight Segments color coding button at the top of the middle pane. It should look like the drawing on the next page.
14
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Criticality and Segmentation
13. Think about where you could install valves to minimize the size of this outage segment. 14. If you have time after you answer the questions, insert additional valves or pipes to improve the system further.
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
15
Results Table
Results Table Result Max number of Isolation Elements Length of the third longest outage segment (ft) System Demanded Flow (gpm) System Supplied Flow for third largest segment (gpm) Length of second longest outage segment (ft) (Improved System)
16
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. Why is it undesirable to have segments where a large number of valves are needed to shut down the segment?
2. What do outage segments show?
3. Would you expect there to be a correlation between the length of distribution segments and system shortfall.
4. Would you expect the same results for a steady state and an EPS criticality analysis?
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
17
Workshop Review
Answers Result Max number of Isolation Elements
9
Length of the third longest outage segment (ft)
7,247
System Demanded Flow (gpm)
610
System Supplied Flow for third largest segment (gpm)
445
Length of second longest outage segment (ft)
3,071
(Improved System)
1. Why is it undesirable to have segments where a large number of valves are needed to shut down the segment? More difficult to shut down system making it more likely that some valves will be inoperable, thus spreading the outage to additional customers.
2. What do outage segments show? They show the impact of an outage. Sometimes, even in looped systems, there may be significant number of downstream customers out of service.
3. Would you expect there to be a correlation between the length of distribution segments and system shortfall. In general, the shortfalls will be correlated with the length of the segment because larger segments have more demand. However, a failure of a key segment, no matter how small, can place a large number of customers out of service. The size of the outage segment is more important in terms of criticality than the size of the segment.
4. Would you expect the same results for a steady state and an EPS criticality analysis? For this system, yes, because no storage tanks were involved. If there were storage tanks, the EPS and steady results would be very different once the tanks drained. 18
Analysis of Valving and Critical Segments Copyright © December-2008 Bentley Systems Incorporated
Hydraulic Transient Modeling
Page 10-1
Hydraulic Transient Modeling Featuring HAMMER® An Overview
Learning Objectives At the end of this session you should be able to: • Understand the basic characteristics of transients • Recognise the risks of transients • Learn about the transient calculation methods • Learn what the Hammer tool can do
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-2
What is a Transient?
Pressure
Shut off
New steady state Time
What is a Transient? Propagation of energy from one location to another… c) Uneven Filling Rate…
…results in…
…Mass Oscillation V = 1 to 20 m/s
ΔH=v v/2g
d) Sudden Gate Opening…
…results in…
ΔH=a Δv/g
…Waterhammer (Transient Pressure Wave) 300toto1000 14000 m/s Va==250 m/s
Pipe L
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-3
Water Hammer Damage !
Water Hammer Damage !
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-4
Sub-atmospheric Pressure a) Excavated Pipe Section at Leakage Location
b) Pipe Joint Jammed by Sand & Dust Residue
c) Sample of Failed Pipe Joint
Pressure Wave Properties • Transients move as pressure waves • a = wave speed • The Wave Speed depends on: – – – – –
Fluid Pipe material Joints Presence of dissolved gas Anchoring
• Time of travel = L/a • Characteristic time = 2L/a
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-5
Pressure Wave Speed Calculation Korteweg equation for wave speed in a pipe:
Ev = Young's modulus (pipe) E = bulk modulus (liquid) ρ = liquid density Ψ = pipe support index μ = Poisson's ratio D/e = dimension ratio (DR)
Characteristic Time: 2L/a • Every system has a characteristic time, 2L/a: – L is the longest possible path through the system (e.g. from pump to reservoir) – a is the pressure wave speed: 300 to 1400 m/s
• 2L/a is the time required for a pulse to travel to the far end, then return: – Fractions of a second for a short suction line – Tens of seconds for a forcemain – Minutes for long-distance transmission lines
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-6
System Response to Change • Compared to 2L/a, valve movements or pump operations are: 0 = Instantaneous (e.g. phase change) ≤ 2L/a = Rapid, requires elastic theory (Method of Characteristics) >
2L/a = Gradual, solvable by rigid-column theory
>> 2L/a = Slow, use rigid-column theory (or even WaterCAD Extended Period Simulation)
• HAMMER uses elastic theory by default
What Causes Transients? Any change in momentum that is “rapid” compared to the characteristic time: 2L/a (usually a few seconds) • Power failure
• Start/Shift/Shut-down
• Control/component failure
• Valve operations & air
• Human error
• Process changes, heat/cool
H .G
.L.
Reservoir
Pump
Check V alve
H.G.L.
H.G.L.
Fl
Penstock Governor
ow
Sump
Generator
Valve
F lo
w Gate
Tailrace
Turbine
Pump
Copyright © 2008 Bentley Systems Incorporated
Turbine
V alve
Dec-08
Hydraulic Transient Modeling
Page 10-7
What is the Impact of Transients? • Joukowski’s / Allievi equation estimate transient pressure rise due to an instantaneous change in momentum: – dH = dV (a / g ) • where: – a = 1000 m/s concrete or – a = 300 m/s plastic
• 1 m/s change (dV) can cause an upsurge (dH) of 100 m or 10 bars! • Also be aware of thrust force, oscillations and resonance!
Why Worry About Transients? • Positive transients can break pipes • Transients can cause pipes to shift • Negative transients can collapse pipes • Negative transients can suck contaminated water into pipes • Injuries or death can occur if staff are present!
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-8
Assessing System Vulnerability “Hammer” Modeling (1990’s) Run HammerTM to find out! M in ut es
• Monitoring systems can not usually measure transients fast enough, or for enough different causes and locations.
SURGE ANALYSIS TOOLS
th on
Graphical Analysis (1960’s)
s
• Modern models make it possible to model an entire system
Days
M
• Field data used to calibrate model
Computer Analysis (1970’s)
Rule of Thumb or Rule of Dumb
Unsteady Pipe Flow Equations • Conservation of mass
δH δH a 2 δV +V =− δt δx g δx
• Conservation of momentum (e.g. energy)
δH δV 1 δV =− +V + f (V ) g δt δx δx
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-9
Methods to Analyze Transients • Arithmetic, e.g. Joukowski equation – Makes many assumptions but a useful rule-of-thumb
• Graphical method and design charts – Popularized by Parmakian. Many charts by Fok. Time-consuming.
• Implicit method (two characteristic equations indexed by time) • Linear analysis method – Linearize friction to study oscillatory behavior and dampening
• Wave-plan method (discrete cumulative disturbances) • Perturbation method (expands nonlinear friction term) • Method of characteristics, e.g. MOC – Converts full Navier-Stokes equations to solvable form – Very widely-used and thoroughly calibrated/validated
Head-loss Equations • Darcy-Weisbach equation
• Hazen Williams equation — (k=6.79 for SI and 3.02 for US unit)
• Manning’s equation — (k is 1.0 for SI and 1.49 for US unit)
Copyright © 2008 Bentley Systems Incorporated
hL = f
L V2 D 2g
1.85
kL V hL = 1.16 D C
V 2n2 L hL = 2 4 / 3 k R
Dec-08
Hydraulic Transient Modeling
Page 10-10
Steady vs. Unsteady Friction • Steady friction does not account for all damping mechanisms 250
Steady
Quasi-Steady
Transient
Steady 230
Head (m)
Quasi-steady Unsteady (Transient) 210
190 0
5
10
15
20
25
Time (s)
Types of Transient Theories • Rigid column theory
ΔH =
L dV g dt
• Elastic theory
ΔH =
a ΔV g
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-11
Elastic vs Rigid-Column Theory Maximum Transient Head Envelopes for a Pumping System Comparison of rigid and elastic theories: Max. Head (Elastic) Max. Head (Rigid)
Reservoir Steady HGL Static HGL
Min. Head (Rigid) Min. Head (Elastic)
Pipeline Pump Station Reservoir
+
Transient Energy Calculated by Elastic Water Column Theory (EWCT) Transient Energy Calculated by Rigid Water Column Theory (RWCT)
Boundary Conditions & Reflections • Boundary Conditions – Orifices to atmosphere & consumption – Dead-ends, reservoirs, and tanks (reflections) – Operating equipment such as valves & pumps
• Changes in Topology – Sudden change in diameter – Branching – Looping
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-12
Water Column Separation • If pressure < vapor pressure, liquid vaporizes • This is called column separation • Water column rejoins once the pocket collapse • Effect of water column separation
What is the Role of Pumps? • Surges and Water Hammer happens if pumps start/stop too quickly • Variable Speed pumps, soft starts, discharge control valves minimize transients during normal operation • Hammer can help set safe restart delays & ramp times for motor controller or PLC • Pre-start safety audits, re-commissioning plans
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-13
What about Surge Protection? • Specialized valves, tanks or pipe configurations • Need to be installed at specific locations • Need to inspect and maintain carefully! • Passive protection is best if available: – Elevated tanks can isolate one system from another – Bypass lines around valves and check valves – Strong, vacuum-resistant pipes and joints
• Need well-trained operators & fire fighters • Need high and low transient risk map
HAMMER Transient analysis and water hammer modelling • Assess safety and vulnerability of water systems • Avoid catastrophic failure of pipes & equipment • Model and simulate any transient event • Simulate any surge protection device • Complete integration with WaterGEMS/CAD Prevent system damage Develop cost-effective surge control strategies Trim construction and O&M budgets Model any surge protection device Minimize wear and tear on pipes Simulate any transient condition Design and operate with greater reliability Eliminate costly over design Ensure the longevity of your water system Prepare for power failures Protect your operators Improve water quality Minimize service interruptions
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Hydraulic Transient Modeling
Page 10-14
WaterCAD/GEMS vs HAMMER WaterCAD/GEMS
HAMMER*
Steady or gradually varying flow
Rapidly varying or transient flow (tracks changes in momentum)
Time step ~ 1 min -1 hour
Time step ~ 0.01 sec
Incompressible, Newtonian, single-phase fluids
Slightly compressible, two-phase fluids (vapour and liquid) and two-fluid systems (air and liquid)
Full pipes.
Closed-conduit pressurized systems with air intake and release at discrete points
* Transient numerical engine
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Dec-08
Hydraulic Transient Modeling
Page 10-15
The End Transients are important - You can model transients to prevent problems
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-1
Optimal Calibration Darwin® Calibrator
Optimization • 2 Types – Darwin (GA) – Manual
• Considerable research interest • Adjust C and demand • Can match results (flow and head) well • System of equations underdetermined – Not unique solution – Can’t tell if answer right
• Genetic algorithms
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-2
Darwin® Calibrator Module Including in WaterGEMS - Addition in WaterCAD • Theory of natural selection developed in the 70’s • Applied to water systems in the 90’s • Optimization through genetic algorithms • Uses multiple field data sets to calibrate: Roughness, Demands and States • It generates tests of successive populations
•Comparison of Field data: •Pressures or gradients at nodes • The strong will survive •Flows in pipes, pumps, and valves
Genetic Algorithm Process • Guess at solutions • Find model prediction • Calculate fitness • Use fittest solution to seed next generation • Make up new solutions by crossover and mutation • Continue until no better solution is found or max generations are reached
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-3
Need Indicator of Fitness of Solution • Measures difference between model and field data • Fitness = [H i (obs ) − H i (model )]
2
• Low value of fitness = good solution
Fitness Calculation • Min squares difference F=
1 wH
(H
− H obs ) + 2
mod
1 wQ
(Q
− Qobs )
2
mod
• Min absolute value differences F=
1 wH
H
mod
− H obs +
1 wQ
Q
mod
− Qobs
• Min worst point F=
1 1 max H mod − H obs + max Qmod − Qobs wH wQ
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-4
How many solutions are there?
• You know that the C-factor is somewhere between 60 and 100 for four pipes • Possible C-factor range 60, 70, 80, 90, 100 • Possible solutions = 54 = 625 • What about 10 pipes?
104=?
• Enumeration is difficult • You have got observations of system head
Fitness Derivation Example: Find initial fitness… 3.7
6.4
2.9
12.9
3.1
15.0
[80,60,70,70] [60,70,100,90] [70,80,80,90] [60,60,100,70] [80,80,80.70] [60,100,100,70]
fitness improves… 2.8
4.2
5.6
0.8
2.1
1.6
[80,70,80,80] [60,70,90,80] [70,60,80,90] [80,80,90,70] [80,80,70,70] [70,80,80,90]
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-5
Fitness Derivation 2.8
4.2
5.6
0.8
2.1
1.6
[80,70,80,80] [60,70,90,80] [70,60,80,90] [80,80,90,70] [80,80,70,70] [70,80,80,90]
0.8
1.2
0.4
0.1
0.3
0.9
[80, 80, 70, 90] [70,80,90,90] [80,90,80,90] [80,80,90,90] [80,90,90,90] [90,90,80,80]
Fitness of Best Solution
Fitness levels off, optimal solution identified
Error in measurement or discretization
Generation Number
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-6
Darwin ® Calibrator Options • Fitness tolerance • Max trials • Non-improvement generations
• Era generation number • Population size • Cut probability
• Solutions to keep
• Splice probability
• Max era number
• Mutation probability • Random seed
Pipe Grouping • Solutions – mn – m values, n pipe groups – Want to limit solution space
• Combine pipes, nodes into groups with similar properties • Groups selected – – – –
Graphically Selection set Filter Manually
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-7
Example of Field Data • Representative scenario • Observation – Element (J-17) – Attribute (Head) – Value (147 ft)
• Demand adjustments – by multiplier – by fire flow test node(s)
Potential Pitfalls of Field Data • Questionable data – Must screen data
• Inappropriate groups – Lumping new pipe with old
• Adjusting wrong parameter – Correcting demands when C is wrong
• Still need common sense – good judgment
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-8
Error Analysis of Field Data • Given: – – – – –
10,000 ft pipe 12 in. diameter Source at 200 ft End at 50 ft Flow and downstream pressure
• Find: Hazen-Williams C
If Q = 40 gpm, V = 0.1 ft/s …HGL is flat
If Q = 2000 gpm, V = 5.7 ft/s …HGL is steep
Copyright © 2008 Bentley Systems Incorporated
P (psi)
C
87
Infinity
86
25.5
85
14.9
84
11.4
83
9.6
P (psi)
C
40
119.5
39
118.1
38
116.8
37
115.5
36
114.3
Dec-08
Optimal Calibration
Page 11-9
Field Data Must be Sensitive to Parameter Adjustment
dH H (orig ) − H (correct ) = 0 dC C(orig ) − C(correct )
Why is Sensitivity Important?
C(correct) = C(orig ) −
H (orig ) − H(correct) dH/dC
(
dC = −1.85LC - 2.85 1.86VD-1.16 dH
Copyright © 2008 Bentley Systems Incorporated
)
1.85
Dec-08
Optimal Calibration
Page 11-10
19
But where does all of the Water go? Billed water exported Billed authorized consumption
Billed metered consumption
Revenue water
Billed unmetered consumption
Authorized consumption Unbilled authorized consumption System input volume
Unbilled meter consumption Unbilled unmetered consumption Unauthorized consumption
Apparent losses Customer meter inaccuracies
Non revenue water
Leakage on transmission and distribution mains
Water losses Real losses
Leakage and overflows at storage tanks Leakage on service connections up to point of customer meter
Source: IWA “best practice” standard water balance
Darwin ® Calibrator for Leaks • Darwin can find likely leak locations • Leak should be large enough to cause measurable head loss • Works by moving around emitter coefficient – Until HGL’s and flows match
• Two ways to run – Find emitter coefficient – Find leakage node
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-11
Calibrator for Leakage • Model the system using only known/metered demands • Enter system metered flows and pressures • System metered flow > Customer demand • Darwin uses this difference to place leakage/theft at best nodes • Likely leak locations
Running Darwin ® Calibrator Construct Model with CIS Data
Identify Parameters to Adjust
Identify Objective Function
Identify Grouping
Collect Field Data Screen Data
Set Ranges Set Optimization Controls
Run Optimization Repeat until Satisfied
Copyright © 2008 Bentley Systems Incorporated
Apply to Model
Dec-08
Optimal Calibration
Page 11-12
Running Darwin Leak Calibration • Uses differences between known flows and actual flow to suggest leakage “hot spots” • Uses same UI as roughness/demand calibration • Needs good data • Focuses leak detection
Case Study: Darwin Leak Detection Leak repaired, 10 l/s saving Forest Farm
Leakage spots identified with Darwin Calibrator
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-13
Case Study: Darwin Leak Detection • United Utilities, UK • Significant leakage was known to be present • Wanted more than sonic leak detection • Small demand management areas (DMA) with good flow and pressure data • Darwin successfully found leak “hot spots”
Lessons Learned-Darwin Leak Calibrator • Need plenty of good data – System flow – Multiple pressure points – Good metered demand estimate
• Best to use nighttime data – Less impact of uncertainty in roughness
• May need additional data collection
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Optimal Calibration
Page 11-14
Tips for using Darwin Leak Calibrator • Emitter coefficient usually on order of – 1 gpm/psi0.5 (0.1 L/s/m0.5)
• Leak must be big enough to cause measurable head loss • Solve sub-areas individually • Works best for smaller pipes( Pipe.
A Query Builder - Pipe dialog will open. 7. In the Fields list scroll down until you see Material. 8. Double click on Material to make pipe material part of your query criteria. 9. Now click on the equal sign = button. 10. Then select the Refresh Unique Values choices in the Unique Values list.
button to list the possible pipe material
Note: Cast iron and Ductile Iron will be displayed. 11. Double click on Cast iron.
10
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
12. Click OK. Note: Several pipes should be highlighted red on the drawing.
13. Click on the Done
button in the Select toolbar.
You are returned to the Selection Set: Cast Iron window.
Note: The pipes that were highlighted on the drawing will be listed. Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
11
Darwin Calibrator
14. Click OK. 15. The Roughness Groups display will now show a Cast Iron group with 17 items (pipes) in it. 16. Click the New button and add another Roughness Group called Ductile Iron. 17. Follow the same steps as used for Cast Iron to create a Ductile Iron roughness group with the remaining 29 pipes.
Baseline Run You are almost ready to perform a calibration. First, however, you will make a baseline run with existing data. Exercise: Setting up a baseline run 1. Click the New button in the left pane of the Darwin Calibrator dialog and select New Manual Run. 2. Name the run Baseline. Note: You should now see the Roughness tab. 3. Set the roughness multiplier Value for both groups to 1.0 in order to hold C constant for the baseline run.
4. Make sure Baseline is highlighted in the left window pane and select the Compute button to run calculations and view results. 12
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
5. Close the Calibration progress dialog. 6. Select Solutions under Baseline to see the Fitness of the manual run.
7. Click on Solution 1 and then view the Solution and Simulated Results for Average Day, Fire Flow at J-10, and Fire Flow at J-31.
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
13
Darwin Calibrator
8. Use this data to fill in the first column (Initial Run) of the Results Table at the end of this workshop. 9. Also enter the Adjustments and Fitness in the Adjustment Factors table for this run.
Manual Calibration Now, you are ready to run a calibration. For the first run, you will manually guess at an adjustment to see how the model behaves. Exercise: Creating a manual run to reduce C by half 1. To set up the calibration, highlight New Calibration Study-1 in the left pane. 2. Click the New button and select New Manual Run. 3. Name the run Reduce C by half. You should now see the Roughness tab for Darwin Calibrator. 4. Set the roughness multiplier Value for both groups to 0.5 to get a feel for how the model responds to changes in C.
14
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
5. With Reduce C by half highlighted, click Compute to run the calibration. 6. Close the Calibration progress dialog. Note: The model ran a simulation with C factors set to one half the values in the representative scenario. 7. View results by selecting Solutions and Solution 1 under Reduce C by half. 8. Fill in the Results Table for this run.
Note: The agreement is to within a few feet for the average day, not quite as good for fire at J-10 condition and is far off for the J-31 fire. Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
15
Darwin Calibrator
9. Look at the correlation graph between observed and predicted heads by picking the Graph button to open the graph on the next page. 10. You must have Solution 1 highlighted to activate the Graph button.
Optimized Calibration You could spend a lot of time trying to determine what to adjust next; what data is good, what data is not reliable or is less reliable, etc, or you can try an automated calibration instead. Exercise: Step 1 - Setting the calibration criteria. 1. Highlight New Calibration Study-1 in the left window pane, and then select the Calibration Criteria tab. 2. Confirm that the criteria are:
16
Fitness Type:
Minimize Difference Squares
Head per Fitness Point:
1.0 ft
Flow per Fitness Point:
10gpm
Flow Weight Type:
Linear
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
3. Make sure New Calibration Study-1 is still highlighted. 4. Click the New button, and then select New Optimized Run. This creates an Optimized Calibration Run called New Optimized Run-1. Note: In this case, since we only have Roughness groups; that is the only parameter to adjust. 5. You will allow the original roughness to be adjusted by multiplying it by values from 0.5 to 1.5. These values should appear on the Roughness tab by default.
6. Open the Options tab. 7. Set the following values: Fitness Tolerance:
0.001
Maximum Trials:
50,000
Non-Improvement Generations:
100
Solutions to Keep:
8
8. Leave the remaining values on their defaults.
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
17
Darwin Calibrator
9. Make sure New Optimized Run-1 is highlighted, and then click Compute to start the optimization. 10. When finished, close the Calibration progress window. 11. Look at the results of the optimized calibration, and record the values in the Adjust C Only column of the Results Table. 12. Also enter the Adjustments and Fitness in the Adjustment Factors Table for this run. 13. Use values from the best fit solution (Solution No. 1).
18
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
The Fitness for this solution is lower than for the manual solution, which indicates that in terms of matching heads and flows this solution is better. However, the roughness adjustments do not make much sense. Why would lined Ductile Iron pipe have a C-factor of 91 while old Cast Iron pipe have a C-factor of 135? Maybe you were trying to adjust the wrong things? Possibly the error in your original results was due to errors in demand allocation. Let us try adjusting demands.
Demand Adjustments In this system, the observed data were not taken during an average time, but rather during the middle of a day when demands are above average. It is felt that commercial demands peak higher than residential (or fixed) demand nodes. So you will set up two demand adjustment groups: Residential and Commercial. System zoning maps show that commercial customers are located at Junctions J-2, J10, J-13, J-16, J-22, J-27, J-28, and J-30. Exercise: Creating the commercial demand group 1. Highlight New Calibration Study-1 in the left pane, and select the Demand Groups tab. 2. Create a demand group and label it Commercial. Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
19
Darwin Calibrator
3. Click in the Element IDs field, and then on the ellipsis to open the Selection Set: Commercial dialog. 4. Click on the Select from Drawing button and on the drawing pick the commercial zone nodes (J-2, J-10, J-13, J-16, J-22, J-27, J-28, and J-30).
5. Then click on Done. The eight nodes will be shown in the Selection Set: Commercial dialog. 6. Click OK. 7. Now create a second Demand Group called Residential that will contain the remaining nodes in the network. 8. This time, when you select nodes from the drawing use a window to choose all of the nodes at once. 9. Use the Remove button to deselect the Commercial nodes.
20
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
10. Then click on Done and OK. Note: You should now have two Demand Groups: Commercial with 8 items (junction nodes) and Residential with 21 items.
You are now ready to try another optimized calibration. This calibration will build on your previous runs. Exercise: Running another optimized calibration using the new demand groups 1. With New Optimized Run-1 highlighted, click the New button and select New Optimized Run. 2. Accept the default name New Optimized Run-2. 3. Click the Options tab and set the Maximum Trials to 50,000 and the Solutions to Keep to 4.
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
21
Darwin Calibrator
4. Select the Demand tab and see that the Minimum, Maximum and Increment values under the Demand tab are set to default values of 0.50, 1.50, and 0.10. 5. Highlight New Optimized Run - 2 in the left pane and click Compute. 6. Close the Calibration progress window. 7. Record the Solution 1 results in the Optimal column of the Results Table. 8. Also enter the Adjustments and Fitness in the Adjustment Factors Table for this run. Note: These look better than the previous results in terms of rational adjustments to C and demands. 9. Review a graph of Solution 1 results.
Saving Optimal Solution We are now going to export the best fit results from our calibration to a scenario. Exercise: Exporting calibration data to a scenario 1. Select Solution 1 from the New Optimized Run - 2 and click on the Export to Scenario button at the top of the left pane. Note: Default names are automatically selected. You can rename the scenario and alternatives you are creating as you choose.
22
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Darwin Calibrator
2. Select OK to export the data. You should receive the following confirmation:
3. Go to the Scenarios manager and check to see that the new calibration scenario has been created.
4. Open the Alternatives manager and confirm the corresponding physical and demand alternatives also were created.
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
23
Advanced Exercise – Measurement Errors
Advanced Exercise – Measurement Errors If you have time, try this exercise. Let us say that you only took measurements during normal demands and you were not very careful in calibrating your gages. Your data is in the table below: Location
Corresponding HGL (ft)
Location
Discharge (gpm)
J-1
165
PUMP
690
J-2
159
J-4
162
J-8
158
J-12
164
J-13
161
J-23
155
J-32
157
Exercise: Creating the calibration run with errors 1. Build a new Field Data Snapshot called Avg. Day w/errors using the above field data.
24
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Advanced Exercise – Measurement Errors
2. With New Optimized Run-2 highlighted, click the New button and select New Optimized Run. 3. Name it Optimized with errors. 4. Set the Maximum Trials to 50,000 on the Options tab.
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
25
Advanced Exercise – Measurement Errors
5. Select the Field Data tab; uncheck the Is Active? box for everything except Avg. Day w/Errors.
6. Select Compute and record the results in the Results Table. 7. Also enter the Adjustments and Fitness in the Adjustment Factors Table. 8. Answer the questions following the Result Tables.
26
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Results Tables
Results Tables Average Day Node
HGL
Initial Run
½ C-factor
Adjust
Optimal
Data
Optimized
Observed
(ft)
(ft)
C only
(ft)
Error
w/Error
(ft)
(ft)
(ft)
J-1
166
165
J-2
157
159
J-4
160
162
J-8
160
158
J-12
162
164
J-13
161
161
J-23
160
155
J-32
160
157
PUMP (gpm)
679
690
Fire Flow at J-10 Node
HGL
Initial
½ C-factor
Adjust
Optimal
Observed
Run
(ft)
C only
(ft)
(ft)
(ft)
J-1
150
J-10
138
J-13
143
PUMP (gpm)
763
(ft)
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
27
Results Tables
Fire Flow at J-31 Node
HGL
Initial
½ C-factor
Adjust
Optimal
Observed
Run
(ft)
C only
(ft)
(ft)
(ft)
J-1
144
J-13
132
J-31
111
PUMP (gpm)
790
(ft)
Adjustment Factors
Initial
½ C-
Adjust
factor
C-only
Optimized
Optimized w/error
Cast Iron Ductile Iron Commercial Residential Fitness
28
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. What would happen if you relied on a model that only adjusted C-factor?
2. Did changing the C-factors have a bigger effect on HGL in the static or fire flow runs? Why?
3. What was the lesson learned when you tried to run optimal calibration at low demand with some small errors in the data?
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
4. If you could get more data, what data would you get?
5. In a real system would you expect all the commercial customers to have the same demand adjustments?
6. What accuracy would you expect to get with real HGL measurements?
30
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Workshop Review
Answers Average Day Node
HGL
Initial Run
½ C-factor
Adjust
Optimal
Data
Optimized
Observed
(ft)
(ft)
C only
(ft)
Error
w/Error
(ft)
(ft)
(ft)
J-1
166
166
176
166
166
165
165
J-2
157
162
163
162
157
159
158
J-4
160
160
160
160
160
162
160
J-8
160
160
161
161
160
158
160
J-12
162
163
168
163
162
164
161
J-13
161
162
165
162
161
161
160
J-23
160
161
162
161
160
155
160
J-32
160
162
165
162
161
157
160
PUMP (gpm)
679
682
623
683
680
690
684
Fire Flow at J-10 Node
HGL
Initial
½ C-factor
Adjust
Optimal
Observed
Run
(m )
C only
(ft)
(ft)
(ft)
J-1
150
155
149
151
150
J-10
138
146
111
141
138
J-13
143
150
129
146
143
PUMP (gpm)
763
737
770
757
762
(ft)
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Workshop Review
Fire Flow at J-31 Node
HGL
Initial
½ C-factor
Adjust
Optimal
Observed
Run
(ft)
C only
(ft)
(ft)
(ft)
J-1
144
151
134
146
144
J-13
132
141
97
130
132
J-31
111
124
38
106
111
PUMP (gpm)
790
761
837
781
790
½ C-
Adjust
factor
C-only
Optimized
Optimized w/error
(ft)
Adjustment Factors
Initial
32
Cast Iron
1.0
0.5
1.5
0.6
0.8
Ductile Iron
1.0
0.5
0.7
1.0
0.8
Commercial
N/A
N/A
N/A
1.5
1.4
Residential
N/A
N/A
N/A
1.2
1.5
Fitness
27.368
459.206
4.481
0.076
5.629
Automating Calibration using Darwin Calibrator Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
1. What would happen if you relied on a model that only adjusted C-factor? You would end up adjusting the wrong parameter to get calibration. HGL would be right but C and demand are wrong. This is an example of calibration by compensating error.
2. Did changing the C-factors have a bigger effect on HGL in the static or fire flow runs? Why? Much more dramatic effect on fire flow runs because of higher velocity.
3. What was the lesson learned when you tried to run optimal calibration at low demand with some small errors in the data? When head loss is on same order of magnitude as error in head loss, the calibration does not know what to adjust.
4. If you could get more data, what data would you get? Would run some actual C-factor tests on cast iron pipes.
5. In a real system would you expect all the commercial customers to have the same demand adjustments? No, they would be different.
6. What accuracy would you expect to get with real HGL measurements? It depends on care taken and instruments used. With GPS elevations and quality gages you can get +/- 2 ft accuracy; with topo map and average quality gage, +/- 10 ft.
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Piping Optimization
Page 12-1
Piping Optimization Darwin Designer
Optimization • Why not have model design system? • Considerable research • Difficulties – – – – – –
Inequalities [p > P(min)] Discrete sizes Local minima Difficult to quantify reliability Handling uncertainty Real goal – not cost minimization
• Darwin GA Optimization
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Piping Optimization
Page 12-2
What is the Objective? • Build the minimum you need at the minimum cost • Build as much as you can given the budget • Tradeoff between cost and performance
Darwin Objectives • Minimize cost • Maximize benefit • Multiobjective tradeoff
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Piping Optimization
Page 12-3
Darwin Actions • New pipe – must specify – – – – –
cost function roughness material and range of diameter 0 diameter means pipe is optional
• Rehab – must specify – – – –
action cost function post-rehab diameter post-rehab roughness
Darwin Costs • Installation Cost - $/ft x ft as f(D) • Rehab Cost - $/ft x ft as f(D) for each rehab action type • Different installation cost functions can be specified for different pipes – – – –
Central city State highway Old Subdivision New Street
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Piping Optimization
Page 12-4
Darwin Benefits • Need a way to measure capacity in excess of the minimum • Darwin uses the excess pressure at key nodes to evaluate this capacity • Two formulations – Unitized – Dimensionless
Quantifying Benefits
Unitized
1 events Benefit = n i
nodes
(P
ij
− Pij ( goal ))
j
Dimensionless
Benefit =
Q ij j Q itot
event node
i
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Pij − Pij ( goal ) P ( goal ) ij
b
Dec-08
Piping Optimization
Page 12-5
A
Inferior B
C
Benefit
Noninferior
Cost
1 Pareto front
2 3
4
Benefit
5
6
Cost
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Dec-08
Piping Optimization
Page 12-6
Levels of Darwin Data • Design study – data entry (Representative Scenario) – Design event • • • •
Demand Adjustments Pressure constraints Flow constraints Boundary conditions
– Design groups (which new pipes) – Rehab groups (which existing pipes) – Option groups • Cost functions • Rehab actions
– Design type (min cost, max benefit, tradeoff)
• Design run – individual run
For a study or its components you can • Create • Copy • Rename • Delete • Compute (for design run)
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Piping Optimization
Page 12-7
Preliminaries Before entering Darwin Designer • Set up representative scenario • Lay out pipes to be designed • Give proposed pipes good names • Lay out and specify tanks, pumps, reservoirs that will be on line
Demand Adjustment (Design Event) • Time • Demand multiplier • Alternate demand alternative • Junction demand adjustments
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Piping Optimization
Page 12-8
Pressure and Flow Constraints (Design Event) • Specify min and max pressure – Globally – Selection set – Specific nodes
• Can set max pressure very high • Specify min and max velocity • Node pressure included in benefits – Globally – Specific nodes
Boundary Condition (Design Event) • Uses tanks levels, pump status, etc. from representative scenario • Can override – – – –
Tank level Pump status (speed) Valve settings Pipe status
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X
Dec-08
Piping Optimization
Page 12-9
Design Groups • Identifies pipes to be candidates for design • Group pipes with common diameter • Enables Darwin to run effectively • For m possible sizes and n groups – mn possible trials – Keep n reasonable
• Give groups logical names 6
12
10
8
Option Groups • Design – Cost function – New pipe roughness – Material
• Rehab – – – –
Action (clean, slipline) Pre vs. Post diameter Pre diameter vs. unit cost Pre diameter vs. Post roughness
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Diameter
Dec-08
Piping Optimization
Page 12-10
Design Runs • Optimized – Use genetic algorithm – Views many solutions
• Manual – User specifies sizes and actions – Tests design events against single solution
Design Run • Select options from Design Study • Design events • New pipe groups • Rehab groups • Options – GA Parameters – Stopping criteria – Top Solutions
• Compute
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Piping Optimization
Page 12-11
Outputs (for each top solution) • Pipe with size (action) and cost • Comparison with constraints • Export to scenario • Copy to clipboard
Designer Tips • Use events that control sizing • Considering multiple events improves reliability • Keep projects that interact in same design run • Check tank refill by forcing inflow • Some nodes can not reach min pressure • Make sure you have a feasible solution • Skeletonizing helps GA run faster
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Piping Optimization
Page 12-12
Using Design Optimization Construct Model
Prepare Demand Estimates
Formulate Benefits
Identify Constraints
Formulate Alternative Plans
Identify Alternative Pipes and Routes and Groups
Assemble Cost Data
Run Optimization
Review Results and Repeat as Needed
Set Optimization Parameters Make Design Decisions
Designer Example
Min Cost
Max capacity
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Min cost w/loops
Max Reliability
Dec-08
Piping Optimization
Page 12-13
Design Decisions • Engineer must still make decisions • Darwin just enumerates trials quickly • Darwin enables you to look at more – Design events – Outages – Design alternatives
The End Darwin Designer makes design work easier
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Automating Design using Darwin Designer Workshop Overview In this workshop, you are going to size pipes for a new commercial site that will be constructed in an existing system. You must provide a 3000 gpm fire flow to the site on max day at a minimum pressure of 20 psi and a pressure of at least 40 psi during peak hour conditions at the site. There are two pipes that must be sized within the customer’s site plus some additional piping that is needed in the distribution system to bring water to the site. You will set up Darwin Designer to find the least cost solution and then you will look at some tradeoffs with other options.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Model Calibration
WaterCAD/GEMS System Planning and Operation
Workshop Objectives After completing this workshop, you will be able to:
Set up and use Darwin Designer to help you in designing a system
Perform a tradeoff analysis
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
1
Getting Started
Getting Started This short section will get you familiar with the model that you will be using Darwin Designer on. Exercise: Setting up for Darwin 1. Start WaterGEMS V8i and open the file called Darwin_Designer.wtg.
Look on the east side of the system for node J-500 which is the new site. It is served by pipes P-500 and P-501 which must be sized and installed. However, the system does not have excess capacity in this area and simply connecting those pipes into the grid will not provide sufficient fire flows. That area needs to be connected back into some larger pipes. There are three major directions through which this can be done:
From the West through pipes P-600 through P-601 From the North through pipes P-700 through P-702 From the South through pipes P-800 through P-804
Note: The proposed pipes have all temporarily been assigned diameters of 1 inch and show up as gray lines in the drawing. 2. Compute
2
the Avg day scenario.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Getting Started
3. Review the pressures and velocities in the pipes to check to make sure that the existing system is in reasonable shape before you start. 4. Open the Junction FlexTable and confirm that there are no nodes that fail to meet the 20 psi and 40 psi pressure standard for average day conditions.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Darwin Designer
Darwin Designer Now we are going to begin to build the data needed for a Darwin Designer run. We will first focus on creating a design event. Exercise: Creating a new Designer Study 1. Open Darwin Designer by clicking the Darwin Designer Analysis > Darwin Designer.
button or by selecting
You need to create a new Designer Study. 2. Click the New button and select New Designer Study. 3. Name the new design study Least Cost Design. 4. Check that the Representative Scenario is Avg day.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Darwin Designer
Exercise: Establishing a Design Event 1. Click on the Design Events tab. 2. Click the New button on that tab. 3. Click the Rename button and name the new design event 3000 Fire at J-500.
4. Click OK. Exercise: Setting demand constraints for the design event 1. On the Design Events tab in the right window leave the Start Time and Design Time at 12:00:00 PM and the Time from Start (hours) at 0.0. Note: The Design Event to be tested is a fire flow under maximum day demands. 2. Enter a Demand Multiplier of 1.5 to convert average demands to max day demands. 3. In the lower half of the Design Events tab, select the Demand Adjustments tab. 4. Click the New button. 5. Click in the Node field and select the ellipsis (…). Note: This will bring you to the drawing pane. 6. Click on J-500 on the east side of the system. 7. When you are brought back to the Darwin Designer window, enter an Additional Demand for J-500 of 3000 gpm.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Darwin Designer
Next, you need to set pressure criteria. Exercise: Setting the pressure constraints for the design event 1. Select the Pressure Constraints tab. 2. Click on the Select from Drawing
button.
Note: This will bring you to the drawing pane. 3. On the Select toolbar click on the Query Junctions.
button and select Network > All
Note: This will highlight all the junction nodes in the model. 4. Click the Done
button on the Select toolbar when you are done.
5. Back on the Pressure Constraints tab; confirm that you have 148 nodes listed in the table. 6. Right click the Override Defaults? column heading and select Global Edit. 7. On the Global Edit dialog select the Value box and click OK. 8. Use Global Edit again to set a Minimum Pressure of 20 psi and a Maximum Pressure of 200 psi at all nodes. Warning: Do not put check marks in the Consider Pressure Benefit? column.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Darwin Designer
Exercise: Selecting the pipes to size using Design Groups Next you need to create some design groups because you will not want to change the pipe size at every block. For your study you will want to create four design groups representing the three directions from which you can bring water to the site, plus a group for the two pipes at the site. 1. Select the Design Groups tab. 2. Click the New button. 3. Rename the new design group Internal and click in the Elements IDs field. 4. Click on the ellipsis (…).
This opens the Selection Set: Internal dialog. 5. Click the Select from Drawing button and select pipes P-500 and P-501. Note: These pipes are connected to J-500.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Darwin Designer
6. Click the Done button once the pipes are selected and then click OK on the Selection Set: Internal dialog. 7. Repeat steps 2-6 to create three additional groups with the following names and pipes based on the direction from which the water will reach the site: Name of Design Group
Pipes in Design Group
West
P-600, P-601
North
P-700, P-701, P-702
South
P-800, P-801, P-802, P-803, P-804
Note: The pipe numbering was set up with these groups in mind. This may not always be the case. When done, the Design Groups tab should look like the following:
Exercise: Entering Costs and Roughness Data Cost and roughness data for the new pipes are specified on the Costs/Properties tab. 1. Select the Costs/Properties tab. 2. Make sure New Pipe is selected. 3. Click the New button and select Design Option Groups.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Darwin Designer
4. Name the new group to Cost New. You will now enter the data for the pipes that must be installed during the project. 5. Click in the Material field and select the ellipsis (…). 6. In the Engineering Libraries window expand Material Libraries and MaterialLibrary.xml. 7. Select Ductile Iron from the list and click Select. 8. Make sure all the pipes you enter have a Hazen-Williams C of 130 and are made of Ductile Iron. Note: You can use the Material ellipsis and Material Libraries to select Ductile Iron, or you can type the words in the Material field. 9. Enter the costs associated with each Diameter listed below: Diameter (in)
Unit Cost ($/ft)
6
55
8
60
10
80
12
105
16
120
When complete, the table should look like the one below:
Note: Pipes that use this option group will need to be installed (i.e. there is no diameter). However, some of the pipes are indeed optional. A new option group will be created from the existing group for these pipes. Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Darwin Designer
10. With Cost New selected click the Duplicate
button.
11. Rename the new group to Cost Optional Pipes. 12. Add a new line with $0.00 Unit Cost and a Diameter of 0.0 to account for the fact that no pipe is a viable option for some pipes. 13. Modify the remaining costs shown in the table below: Diameter (in)
Unit Cost ($/ft)
0
0
6
60
8
70
10
90
12
115
16
135
When completed, the table should look like the one below:
14. Select the Design Type tab. 15. Check to make sure that the default of Minimize Cost has been selected for Objective Type.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Darwin Designer
Exercise: Creating a new Optimized Design Run You will now create a new Design Run. 1. With Least Cost Design selected in the left pane, click the New button and select New Optimized Design Run. 2. Rename the run to 3000 Fire at J-500, Min Cost, Pump On, which corresponds to the design event, type of optimization and boundary condition. Note: In setting up the design run, you must pick which design events, design groups and cost functions are to be used. 3. Select the Design Events tab. 4. Make sure that the Design Event, 3000 Fire at J-500 is marked as Active.
5. Select the Design Groups tab. 6. Make sure that all four Design Pipe Groups are Active for this run.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Darwin Designer
7. Assign the following Design Pipe Groups to their associated Cost/properties using the dropdown menu: Design Pipe Group
Cost/properties
Internal
Cost New
West
Cost Optional Pipes
North
Cost Optional Pipes
South
Cost Optional Pipes
8. Select the Options tab. 9. Leave the GA Parameters and Stopping Criteria sections alone. 10. Set the Solutions to Keep field to 10.
Now that you are all set up, you can run Darwin Designer. 12
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Darwin Designer
Exercise: Running Darwin Designer 1. Make sure that the design run 3000 Fire at J-500, Min Cost, Pump On is highlighted. 2. Click the Compute
button.
3. When Darwin Designer has completed its run, Close the Designing… dialog box.
Now you can look at the results of your runs. Exercise: Reviewing results 1. Select Solutions in the left pane. 2. Review the Solutions listed in the right pane. 3. Look at the costs for the top 10 solutions and see how much they differed.
4. Highlight the individual solutions and review the results. 5. Complete the first Results Table at the end of the workshop. Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
13
Exporting the Solution
Exporting the Solution Now you will export Solution 1 to the Scenarios Manager and set up the maximum day alternative. Exercise: Exporting a solution to a scenario 1. Select Solution 1 and click the Export to Scenario
button.
2. In the Export Design to Scenario dialog, rename the new scenario Least Cost. 3. Check the box for Use Scenario Name for Alternatives to give the same name to your new Physical and Active Topology Alternatives. 4. Check the box for Export Physical Alternative? and Export Active Topology Alternative?.
5. Click OK. 6. Minimize Darwin Designer. 7. In WaterGEMS, switch to the Least Cost scenario. 8. Select Analysis > Scenarios and double click on the Lease Cost scenario. 9. Review the properties of the Least Cost scenario. Note: You will see that it contains the Least Cost Physical and Active Topology Alternatives generated by Darwin, but the Demand Alternative is still set on Average Daily. 14
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Exporting the Solution
Exercise: Creating a maximum day demand alternative You need to set up maximum day demands with 1.5 times average day demands plus a 3000 gpm fire flow at node J-500. 1. Select Analysis > Alternatives. 2. Expand the Demand alternative and click on Base-Average Daily. 3. Click the New button to create a child alternative from it. 4. Name the new child 3000 gpm Fire.
Exercise: Assigning the new demand alternative to the new scenario and computing 1. Select Analysis > Scenarios. 2. Open the Properties window for the Least Cost scenario. 3. Select 3000 gpm Fire as the Demand Alternative.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
15
Exporting the Solution
4. Make sure Least Cost is the active scenario and select Tools > Demand Control Center. 5. Globally multiply all values in the Demand (Base) column by 1.5.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Exporting the Solution
6. Close the Demand Control Center. 7. Locate J-500 on the drawing and double click on the node to open its Properties dialog. 8. Click in the Demand Collection field and then on the ellipsis. 9. In the Demands dialog set a 3000 gpm fire Demand at J-500 with a Fixed Pattern.
10. Close out of the Demands dialog. 11. Compute the Least Cost scenario. 12. Verify that the Pressure at J-500 and all the other nodes is above 20 psi. 13. Check the Velocities in pipes around J-500 to make sure they are not too high. 14. Look at the gray pipes to be sized in the Avg Day scenario and then switch the scenario to Least Cost and see how the pipes change color.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Tradeoff Analysis
Tradeoff Analysis Now that you have found the least cost solution, it is also instructive to examine the tradeoffs between cost and performance. Exercise: Creating the tradeoff analysis study 1. Restore Darwin Designer from the lower window tray. You will modify the already created Least Cost Design Study to convert it to a Tradeoff Analysis. 2. Start by renaming Least Cost Design to Tradeoff Analysis.
Note: For this study, you will want to trade off the benefits of improved performance against cost. The value of this project will be judged partly by how it improves residual pressure at node J-500. The benefit will be measured by the extent to which pressure exceeds 20 psi during the fire. You need to change the Design Type and define how benefits will be calculated during this additional design event. 3. Click on Tradeoff Analysis design study. 4. Select the Design Type tab. 5. Select Multi-Objective Tradeoff as the Objective Type. 6. Set the Available Budget to $500,000. Note: This means that solutions costing more than $500,000 will not be considered. 7. For Benefit Type, select Unitized. Note: This means that the total benefits will have units of psi in this case. 8. Leave the Pressure Benefit fields to 1.0.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Tradeoff Analysis
Exercise: Creating and setting up the new tradeoff design event 1. Select the Design Events tab. 2. Select the 3000 Fire at J-500 Design Event and click the Duplicate button. 3. Rename the Design Event to 3000 Fire Flow Benefit.
4. Click OK. Exercise: Confirming demand data 1. Select the new design event and confirm that the Demand Multiplier is set to 1.5. 2. Select the Demand Adjustments tab on the bottom of the Design Events tab. 3. Verify that the Additional Demand at J-500 is 3000 gpm.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
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Tradeoff Analysis
Exercise: Confirming the pressure constraints 1. Select the Pressure Constraints tab. 2. Confirm Minimum Pressure for all nodes is set at 20 psi and Maximum Pressure for all nodes is set to 200 psi. 3. Sort the Node column in Descending order to easily find node J-500. 4. Check the box for Consider Pressure Benefit? only for J-500.
Exercise: Renaming the design run and verifying it’s data 1. In the left pane, click on 3000 gpm Fire at J-500, Min Cost, Pump on, and rename it to Tradeoff Fire J-500. 2. Select the Design Events tab and make sure only the 3000 Fire Flow Benefit event is Active.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Tradeoff Analysis
3. Select the Design Groups tab and make sure that all 4 design groups are Active. 4. Also make sure that the Design Option Group called Cost Optional Pipes is assigned to the West, North and South groups, and Cost New is assigned to Internal.
5. Select the Options tab and set Solutions to Keep to 20.
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
21
Tradeoff Analysis
Exercise: Computing the tradeoff design run and reviewing results 1. Select Tradeoff Fire J-500 and click Compute. 2. Watch the run and check the message tab when it is done. 3. Close the Designing… dialog box when the run is complete. 4. Select Solution 1 and click on the Graph Plot.
button to display the Pareto Optimal
5. Look at the overview of the non-inferior solutions.
6. Close the graph and review the different solutions to compare results. 7. Choose about 5 of the solutions that cover a range of costs. 8. Write the solution number, benefits, and costs in the second Results Table at the end of the workshop. 9. For the 5 solutions you picked above, look up the pipe diameters, and write them down in the Results Table. 10. Consider how these solutions compare with the least cost solution. 11. Answer the questions at the end of the workshop. 22
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Results Tables
Results Tables 1. For each of the first set of Design Runs, list the pipe sizes and cost (leave blank if pipe not installed), Round cost to thousands of dollars. Solution
Internal
West
North
South
Total Cost ($1000)
1 2 3 4 5
2. For the multi-objective run, list the sizes, costs and benefits for 5 non-inferior solutions. Solution
Internal
West
North
South
Total Cost ($1000)
Benefit
3. What solution would you recommend?
Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
23
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. If you were adding another subdivision on the opposite side of town, should you include sizing those pipes with the pipe sizing for this problem or should you create a new design study?
2. Why did the South piping not get selected as the least cost alternative?
3. How would you force the South pipes not to be eliminated from the solution?
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
4. What do you think would have happened if you included a node that could not reach 20 psi for any combination of pipe sizes (e.g. a node on the suction side of a pump) and what would you need to do to handle that node?
5. How would you decide between non-inferior solutions in the tradeoff analysis?
6. What would happen if you included a lot of nodes on the south side of the system in calculating benefits?
7. Why would you not have used Average Day demands as an event in Designer?
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Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers 1. For each of the first set of Design Runs, list the pipe sizes and cost (leave blank if pipe not installed), Round cost to thousands of dollars. Solution
Internal
West
North
South
Total Cost ($1000)
1
10
10
195
2
8
10
206
3
12
8
221
4
10
10
227
5
16
8
236
2. For the multi-objective run, list the sizes, costs and benefits for 5 non-inferior solutions. Solution
Internal
West
North
South
Total Cost ($1000)
Benefit
10
206
0.702
12
370
1.508
1
8
2
8
6
12
10
253
1.220
7
16
12
308
1.433
18
12
12
496
1.765
8
12
3. What solution would you recommend? If your budget is limiting consider solution 6. Otherwise choose on budget limit.
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Automating Design using Darwin Designer Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
1. If you were adding another subdivision on the opposite side of town, should you include sizing those pipes with the pipe sizing for this problem or should you create a new design study? It depends on whether there likely to be interactions between the piping used to solve each problem.
2. Why did the South piping not get selected as the least cost alternative? It contained the longest (and hence most costly) piping.
3. How would you force the South pipes not to be eliminated from the solution? Not allowing them a zero diameter in the cost table.
4. What do you think would have happened if you included a node that could not reach 20 psi for any combination of pipe sizes (e.g. a node on the suction side of a pump) and what would you need to do to handle that node? You would get a “no feasible solution” message and you would need to set a very low pressure as the pressure constraint for that node (or only enforce pressure constraints for a smaller selection set and not all nodes).
5. How would you decide between non-inferior solutions in the tradeoff analysis? You would need to consider available budget and amount of safety factor you want to build in.
6. What would happen if you included a lot of nodes on the south side of the system in calculating benefits? Those solution’s bigger pipes on the south side would tend to have higher benefits and are more likely to show up as non-inferior.
7. Why would you not have used Average Day demands as an event in Designer? For most situations average day demands do not control pipe sizing.
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Skelebrator
Page 13-1
Skelebrator Automated Skeletonization
All Pipe vs. Skeletonized All Pipe
Skeletonized Model
Skeletonizing Program
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GIS Features to Model Elements Gate Valve
T-fitting
45 bend
Hydrant Lateral
Reducer New Pipe
X -fitting
GIS View
Gate Valve
Model after ModelBuilder
Model after Skelebrator
Why Skeletonize? • Run / open / save faster • Are easier to move / copy • Can be easier to navigate • Can give accurate answers if built correctly
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Skeletonization Example
LEGEND Sampling Points Major Users Tank 12-in Mains Skeleton
Effects of Skeletonization • “The Effects of Skeletonization in Distribution System Modeling” Grayman, Males, Clark, AWWA Computer Conference, 1991. • Constructed four levels of skeletonization: – Level 1: 10” pipes and above and a few loops – Level 2: 10” pipes and above; engineering judgment to include additional important loops – Level 3: 8” pipes and above – Level 4: All-pipe representation
• Examined impacts of skeletonization on prediction of velocity, fire flow, pressure, chlorine residual.
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Four Levels of Skeletonization
LEVEL 1
LEVEL 2
LEVEL 3
LEVEL 4
Effects of Skeletonizationn on a Pressure Node
Pres sure (psi)
77 Skel1
76
Skel2
75
Skel3
74
Skel4
73 72 0
5
10
15
20
25
Hours
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C h lo rin e R e sid u a l (m g /L )
Effects of Skeletonizationn on Chlorine Residual at a Node 1 0.8
Skel1
0.6
Skel2 Skel3
0.4
Skel4
0.2 0 0
5
10
15
20
25
Hours
Effects of Skeletonization on Fire Flow
FIRE FLOW (GPM)
5900 Skel 4
5800 Skeletonization 3
5700 5600
Skeletonization 2
5500 5400
Skeletonization 1
5300 0
200
400
600
800
# OF LINKS
Can you explain this trend?
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Use of GIS • Leads to larger models • Manual skeletonization becomes difficult • Need to automate skeletonization • Can not just arbitrarily remove pipes
Skeletonization Not a Single Operation • Smart Pipe removal • Branch collapsing (trimming) • Series pipe merging • Parallel pipe merging
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Hydraulic Equivalency • Pipe capacity – Same h vs. Q relationship after skeletonizing
• Demand allocation – Total demand not changed
• May be some water quality effects
General Rules • Will not remove non-junction nodes (pumps, control valves, tanks, logical controls) • Will not leave valves and pumps without inlet/outlet • Junctions/pipes/TCV can be removed • Can designate protected elements • Preview – look before you skeletonize • No undo –save before skeletonizing • Only have one scenario in file
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Protection • Pipes and nodes can be protected – – – –
Not removed during skeletonization Protected regardless of operation Not needed for valves/tanks/pumps Protected nodes will not be orphaned
Two step process • Defining operation – Settings – general rules – Conditions – logical statements
• Running operation – Manual – pipe by pipe – Automatic - apply all at once – Preview – view before data changed
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Smart Pipe Removal • Conditions – Very important – Specify for pipe only – Use for removing small pipes
• Settings – Preserve network integrity • Total demand preserved • Nodes connected back to source
– Remove orphaned junctions – Loop sensitivity
• Needed when other methods have been exhausted
Smart Pipe Removal 2 • No adjustments to other pipes • Makes one pass through network • Removal order based on order pipes added to model • Will only remove last pipe in branch • In loop, starts with lowest number pipe • Can preserves demands
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Smart Pipe Removal
Branch Collapsing (Trimming) • Removes pipe/node at end of branch • Settings – Number of levels to collapse (default = 1) – Retain loads?
• Conditions – Which nodes and pipes are candidates
• Useful for eliminating services/laterals
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Branch Collapsing 6 7
4
5
2
Start
4
10
2
28
7
9
Collapse One Level
Collapse 4 or more
Series Pipe Merging • Combines pipes in series • Get rid of point features like open gates and air releases • Conditions – Pipes and nodes candidate for removal
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Series Pipe Merging Settings • Levels of removal – number of pipes • Use equivalent pipes • Equivalent pipes – Keep D – Keep C or ε (roughness)
• Dominant pipe • Load distribution strategy • Apply minor losses • Allow removal of TCVs
Load Distribution Strategy 5
8 in.
10
10
10.7
9.1
6 in.
9
14
(8/(8+6))10=5.7
13.3
(10/(10+14))10=4.1
14.9
15
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Start Equal Distribution Proportional to Dominant Criteria Proportional to Existing Load Use Defined (all to one end)
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Series Pipe 1
2
e
Qe = Q1 = Q 2
he = h1 + h 2 Le = L1 + L2 Le 0.54 De 2.63 Ce = 0.54 Li 4.87 1.85 Di Ci
Le 0.205 Ce 0.38 De = 0.205 Li 4.87 1.85 Di Ci
Similar Formulas for • Darcy Weisbach equation – Solve for k – Iterative solution needed f(R)
• Manning equation
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Naming Equivalent Pipe • Automatic numbering • Best to set prefix or suffix to indicate equivalent pipe – EP-1 – P-1-E
• Tools > Options > “Labeling Tab” • No new nodes are ever created
Parallel Pipe Merging • Levels of removal – number of pipes • Use equivalent pipes • Equivalent pipes – Keep D – Keep C, n – Can not do Darcy-Weisbach ε (roughness)
• Dominant pipe • No nodes removed • Minor losses strategy – Ignore minor losses – 50/50 split – Do not remove if minor loss K > Minimum
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Parallel Pipe 1
2
e
Le = L1 where 1 is dominant
Qe = Q1 + Q 2 he = h1 = h2
Ce =
L0e.54 De2.63
C i Di2.63 L0.54 i
L0e.54 De = Ce
C i Di2.63 L0.54 i
0.38
The Power of Skelebrator 7 pipes, 5 nodes 2 pipes, 1 node
Branch Collapse Parallel Removal
Series Removal Series Removal
Series Removal
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Working with Skelebrator Operations • Save or back up the Model first! • Skeletonize before you build scenarios • Export to .ske file • Import within another project • Within project can – Duplicate – Rename
• Protected elements included in .ske • Skelebrator works with WaterCAD/GEMS
The End Skelebrator - Intelligent reduction in model size
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Skeletonizing a Large Model using Skelebrator Workshop Overview In this workshop, you will skeletonize a model and examine the differences in the results between the methods involving equivalent pipes and those that simply remove pipes. To do this you will examine the effects on the pressure at node A100, the fire flow at that node, and the system head curve at the pump station as the system becomes more skeletonized. Initially, you will only use pipe removal to skeletonize the model. Then you will restart the problem and use a collection of techniques, with minimal use of pipe removal.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Geospatial Data Overview
Workshop Objectives After completing this workshop, you will be able to:
Use Skelebrator and apply all four of its different operations
View system head curves
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
Getting Started This section will walk you through opening the starter file and getting it ready for our Skelebrator runs. Exercise: Opening the WaterGEMS model 1. Start WaterGEMS V8i. 2. Open the file Skelebrator_Start.wtg from C:\Program Files\Bentley\WaterDistribution\Starter. Once open, the schematic should look like the one below, with two scenarios named Base and Fire at A-100.
Exercise: Starting Skelebrator 1. Start Skelebrator by clicking the Skelebrator Skelebrator Skeletonizer.
2
button or by selecting Tools >
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Getting Started
The main Skelebrator Skeletonizer dialog will open.
Exercise: Protecting an element and computing the model The first thing you want to do is protect Junction A-100 so that it is not removed. 1. Select the Protected Element tab, and then click the Select from Drawing button. 2. On the Select toolbar, click the Find
button.
3. In the Find dialog click the Find button again to populate the list with the elements in the model. 4. Click on element A-100 in the list to highlight it. 5. Click OK and then click the Done
button from the Select toolbar.
6. Minimize the Skelebrator Skeletonizer dialog. 7. Select Analysis > Scenarios. 8. Click the down arrow next to the Compute button, and select Batch Run. 9. In the Batch Run dialog select the boxes for the Base and Fire at A-100 scenarios.
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
10. Click the Batch button. 11. You will be prompted with the Please Confirm dialog to confirm that you would like to run two scenarios as a batch, select Yes. 12. When the simulation is complete, select OK and then close the Scenarios manager. Note: The Base scenario should be selected as the active scenario. 13. As you go through the following steps, record the results in the Results Tables at the end of the workshop. 14. Go to the Results table and review it now so you can see the data you should be recording as you go. Exercise: Running a Project Inventory Report of a model 1. Determine the number of pipes and nodes before skeletonization by selecting Report > Project Inventory. 2. On the bottom of the first page of the Project Inventory Report you should see that there are 656 pipes and 517 junctions.
3. Close the Project Inventory Report. Exercise: Using the Find tool 1. Find node A-100 in the schematic by selecting Edit > Find Element. 2. Type A-100 into the top left field of the Properties dialog. 3. Set the Zoom Percent to 75%. 4. Click the Find
button to locate A-100.
5. Close the Properties dialog.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Getting Started
Exercise: Recording pressures for A-100 in both scenarios The schematic has been annotated by Pressure at each node.
Note: The pressure at A-100 for the Base scenario is 42.3 psi. 1. Record this value in the table in the Results Table at the end of the workshop. 2. Switch to the Fire at A-100 scenario from the Scenario dropdown menu on the main screen and see that the pressure at A-100 for this scenario is 31.1 psi.
3. Record this value in the Results Table. Exercise: Viewing the system head curve for PMP-1 1. Switch back to the Base scenario. 2. Use the Find Element tool again to locate PMP-1. 3. Right click on PMP-1 and select System Head Curve. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
The System Head Curve window will appear. 4. Set the Maximum Flow to 2000 gpm and click the Compute button. Your graph should look like the one below:
5. Select the Data tab and look up the head of the System Head Curve at 2000 gpm. 6. Note that the Head is 195.2 ft; record this value in the table in the Results Table. 7. Click Close. 8. Click Yes to save the System Head Curve. Exercise: Creating a backup of our Skelebrator_Start.wtg file So that this file will be available for the second part of the workshop, we will save another copy of the file with a different name. 1. Select File > Save As. 2. Name the file Skelebrator_End.wtg. 3. Click Save. Note: This is the file you will be modifying using Skelebrator, while Skelebrator_Start.wtg is a backup file in case we need it. 6
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
Skelebrator Skeletonizer In this section you will run through the different operations that are available in Skelebrator.
Smart Pipe Removal Exercise: Removing Pipes Less Than 6 inches 1. Back on the main screen your active scenario should be Base, if it is not, change it before you continue. 2. Select View > Zoom > Zoom Extents to see the full view. 3. Restore Skelebrator Skeletonizer and select Smart Pipe Removal on the left hand side.
4. Click the New button and accept the default operation name. Note: There are three tabs along the top of the window: Settings, Conditions, and Notes. 5. Select the Settings tab and adjust the Loop Retaining Sensitivity to 40 by moving the slider bar to the right.
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Skelebrator Skeletonizer
Note: If the numerical indicator does not update automatically as you move the slider, uncheck and recheck the box marked Preserve Network Integrity? to synchronize the displayed number with the position of the slider. 6. Select the Conditions tab and click the Add button. 7. Set the following: Attribute:
Diameter
Operator:
Less Than
Diameter:
6 inches
8. Preview the operation by clicking the Preview be removed.
button to see the pipes that will
9. Minimize Skelebrator to view the drawing.
8
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
10. After your review, restore Skelebrator. 11. Click the Compute button. 12. You will be warned that you are about to perform a process that cannot be undone, select Yes to continue. Note: Always select Yes in this workshop when Skelebrator asks you if you want to continue. The Skelebrator Progress Summary dialog provides information on the pipes and nodes removed from the model.
13. After reviewing the Skelebrator Process Summary, close it and minimize Skelebrator. Now we will evaluate the hydraulic impact of the Smart Pipe Removal procedure. Exercise: Evaluating the hydraulic impact of this Smart Pipe Removal 1. Open the Scenarios manager and Batch Run both the Base and Fire at A-100 scenarios. 2. Select OK when the simulations are complete and close the Scenarios manager. 3. Select Report > Project Inventory. 4. Record the number of pipes and nodes remaining and enter this data in the Results table at the end of the workshop. Exercise: Finding A-100’s Pressure and PMP-1’s System Head Curve 1. As you did before, find Junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the results table at the end of the workshop. 2. Go to the PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the results table at the end of the workshop. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Skelebrator Skeletonizer
Warning: Make sure to switch your scenario to Base before continuing to the next exercise.
Smart Pipe Removal Exercise: Removing Pipes Less Than or equal to 6 inches 1. Restore Skelebrator. 2. With Smart Pipe Removal-1 highlighted in the left pane, select the Conditions tab. 3. Select the existing Attribute Diameter. You will change the condition so that pipes of diameter equal to 6 inches or less are removed. Note: Recall that in the previous pipe removal we removed pipes that were less than 6 inches, but not the 6 inch pipes as we will in this run. 4. Change the Operator to Less Than or Equal.
5. Select the Compute button to run automated skeletonization. Note: You will be warned that you are about to perform a process that cannot be undone. 6. Select Yes to continue. 7. Review the Skelebrator Progress Summary, and then close it and minimize Skelebrator.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
Exercise: Computing the scenarios and reviewing results 1. Go to the Scenarios manager and run the Base and Fire at A-100 scenarios as a Batch Run. 2. Select OK when the simulation is complete and close the Scenarios manager. 3. Select Report > Project Inventory.
4. Record the number of pipes and nodes remaining and enter this data in the Results Table at the end of the workshop. 5. As you did before, go to element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Results Table at the end of the workshop. 6. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the results table at the end of the workshop. Warning: Make sure to switch your scenario to Base before continuing to the next exercise.
Smart Pipe Removal Exercise: Removing Pipes Less Than or Equal to 8 inches You will repeat the process above one more time, this time removing pipes that are less than or equal to 8 inches in diameter. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Skelebrator Skeletonizer
1. Restore Skelebrator. 2. Select Smart Pipe Removal – 1. 3. On the Conditions tab, change the Diameter to 8 inches.
4. Select Compute. Note: You will be warned that you are about to perform a process that cannot be undone. 5. Select Yes to continue.
6. Review the Skelebrator Progress Summary, then close it and close Skelebrator. Exercise: Computing the scenarios and reviewing the results 1. Open the Scenarios manager and run the Base and Fire at A-100 scenarios as a Batch Run. 2. Select OK when the simulations are complete and close the Scenarios manager. 3. Select Report > Project Inventory.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
4. Record the number of pipes and nodes remaining and enter this data in the Results Table at the end of the workshop. 5. As you did before, go to element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Results Table at the end of the workshop. 6. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the results table at the end of the workshop. Note: This exercise shows that removing half the pipes and two fifths of the pipes can affect model results, particularly in high-demand cases. Next, you will try a different approach.
Branch-Series-Parallel Removal Exercise: Opening Skelebrator_Start.wtg, computing and reviewing results 1. Select File > Open. 2. Select Skelebrator_Start.wtg and click Open. At the top of the drawing window, you will note that you have two WaterGEMS projects open, Skelebrator_Start.wtg and Skelebrator_End.wtg. 3. Click on each tab to look at the pipe changes produced by Skelebrator. 4. When finished with your comparison, make sure that the active project is Skelebrator_Start.wtg. 5. Open the Scenarios manager and Batch Run the two scenarios Base and Fire at A-100. 6. Select OK when the simulations are complete and close the Scenarios manager. 7. Select Report > Project Inventory.
8. Record the number of pipes and nodes in the model at the start in the results table at the end of the workshop. Note: You should be back to 656 pipes and 517 nodes. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Skelebrator Skeletonizer
9. As you did before, go to element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Results Table at the end of the workshop. 10. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the Results Table at the end of the workshop. 11. After recording the results, select File > Save As and save the file as Skelebrator_End2.wtg. 12. Click Save. Note the changed name in the project tab above the drawing window. Warning: Make sure to switch your scenario to Base before continuing to the next exercise. Exercise: Protecting junction A-100 1. Start Skelebrator by clicking the Skelebrator Skelebrator Skeletonizer.
button or by selecting Tools >
2. Select the Protected Elements tab, and then click on the Select from Drawing button. 3. On the Select toolbar, click the Find
button.
4. In the Find dialog click the Find button again to populate the list with the elements in the model. 5. Click on element A-100 in the list to highlight it. 6. Click OK and then click the Done
14
button from the Select toolbar.
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
Series Pipe Merging Exercise: Running a Series Pipe Merging 1. Restore Skelebrator. 2. Highlight the Series Pipe Merging option in the left pane. 3. Select the New button and accept the default operation name. 4. Select the Settings tab. 5. Set the Maximum Number of Removal Levels to 5.
Note: No other changes are needed. 6. With Series Pipe Merging-1 highlighted in the left pane, select the Preview button. 7. Minimize Skelebrator to view the drawing.
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Skelebrator Skeletonizer
8. Use the drawing window zoom buttons to zoom to an area where you can see several pipes and nodes. 9. Restore Skelebrator. 10. Select the Manual
button.
11. Select Yes to continue with the skeletonization.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
12. Select the Go To button and you will zoom into E-2582. 13. Click Execute and you will merge one pipe into one that is connected to it in series, creating a single longer pipe. 14. Select Close to return to the Skelebrator window and click the Compute button. 15. Select Yes to automatically merge the remaining pipes.
16. Review the Skelebrator Progress Summary and then close it. 17. Continue without recording results at this point. Note: You will need to remove some pipes because this system has few dead ends or series pipes. Exercise: Running a Smart Pipe Removal for pipes less than 4 inches 1. Highlight Smart Pipe Removal. 2. Click the New button, and accept the default operation name.
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Skelebrator Skeletonizer
3. On the Settings tab, adjust the Loop Retaining Sensitivity to 40. 4. Select the Conditions tab and click the Add button. 5. Create a condition to remove pipes less than 4 inches in diameter.
6. With Smart Pipe Removal-1 highlighted in the left pane, click the Compute button and select Yes to continue.
7. Review the Skelebrator Progress Summary, and then close it. 8. Minimize Skelebrator. Exercise: Computing the scenarios and reviewing the results 1. Open the Scenarios manager and run the Base and Fire at A-100 scenarios as a Batch Run. 2. Select OK when the simulation is complete and close the Scenarios manager. 3. Select Report > Project Inventory.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
4. Record the number of pipes and nodes remaining and enter this data in the Results Table at the end of the workshop. 5. As you did before, go to the element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Step 1 row of the Results Table at the end of the workshop. 6. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the Step 1 row of the Results Table at the end of the workshop. Warning: Make sure to switch your scenario to Base before continuing to the next exercise.
Branch Collapsing Exercise: Executing a branch collapsing run 1. Restore Skelebrator and highlight Branch Collapsing.
2. Select the New button and accept the default operation name. 3. Select the Settings tab, set the Maximum Number of Trimming Levels to a large number, 10. Note: Do not change the Load Distribution Strategy and do not specify any Conditions.
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Skelebrator Skeletonizer
4. With Branch Collapsing-1 highlighted in the left pane, select the Preview button. 5. Minimize Skelebrator to view the drawing.
6. When finished, restore Skelebrator. 7. Make sure that Branch Collapsing-1 is still highlighted. 8. Click the Compute button and select Yes to continue.
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Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
9. Review the Skelebrator Progress Summary and then close it. Note: Now that you have eliminated some branches, you have created more pipes in series. Exercise: Running the Series Pipe Merging-1 to clean up pipes 1. Highlight Series Pipe Merging-1 in the left pane. 2. Select the Compute button and select Yes to continue.
3. Review the Skelebrator Progress Summary report and then close it. 4. Minimize Skelebrator. Exercise: Computing the scenarios and reviewing the results 1. Go to the Scenarios manager and run the Base and Fire at A-100 scenarios as a Batch Run. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Skelebrator Skeletonizer
2. Select OK when the simulation is complete and close the Scenarios Manager. 3. Select Report > Project Inventory.
4. Record the number of pipes and nodes remaining and enter this data in the Results Table at the end of the workshop. 5. As you did before, go to the element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Step 2 row of the Results Table at the end of the workshop. 6. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the Step 2 row of the Results Table at the end of the workshop. Warning: Make sure to switch your scenario to Base before continuing to the next exercise.
Parallel Pipe Merging Exercise: Setting up a Parallel Pipe Merging Operation 1. Restore Skelebrator and highlight Parallel Pipe Merging. 2. Select the New button and accept the default operation name. 3. Select the Settings tab and increase the Maximum Number of Removal Levels to 5. Note: Do not change other Settings or Conditions.
4. With Parallel Pipe Merging-1 highlighted in the left pane, select the Preview button to preview the operation. 22
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
5. Minimize Skelebrator to view the drawing.
6. Restore Skelebrator. 7. Make sure Parallel Pipe Merging-1 is still highlighted, and select the Compute button. 8. Click Yes to continue.
Note: No nodes are removed in Parallel Pipe Removal. 9. Close the Skelebrator Project Summary to return to the main window. Exercise: Trimming branches with Branch Collapsing Operation 1. Highlight Branch Collapsing-1. Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
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Skelebrator Skeletonizer
2. Select the Compute button and Yes to continue. 3. Review the Skelebrator Progress Summary and then close it.
Exercise: Running a Series Pipe Merging Operation to collapse pipes in series 1. Highlight Series Pipe Merging-1. 2. Select the Compute button and Yes to continue.
3. Review the Skelebrator Summary Report and close it to return to the main Skelebrator window. 4. Minimize Skelebrator. Exercise: Computing the scenarios and reviewing the results 1. Go to the Scenarios manager and run the Base and Fire at A-100 scenarios as a Batch Run. 24
Skeletonizing a Large Model using Skelebrator Copyright © December-2008 Bentley Systems Incorporated
Skelebrator Skeletonizer
2. Select OK when the simulation is complete and close the Scenarios manager. 3. Select Report > Project Inventory.
4. Record the number of pipes and nodes remaining and enter this data in the Results Table at the end of the workshop. 5. As you did before, go to the element dialog for junction A-100 and record the Pressure for both the Base and Fire at A-100 scenarios in the Step 3 row of the Results Table at the end of the workshop. 6. Also, go to PMP-1 and record the Head at 2000 gpm from the System Head Curve for the Base scenario in the Step 3 row of the Results Table at the end of the workshop. Note: After Step 2, there was basically no impact on the results for the scenarios and locations at which we are looking due to further Skeletonization. 7. Select the FlexTables dropdown from the toolbar, and select Pipe to view that table. 8. Scroll through the Pipe FlexTable and you will see that some of the pipes created with series or parallel removal, the ones with the P prefix, have non-standard diameters (or C-factors if you chose that setting). 9. If you have time, try to reduce the model to the absolute minimum number of pipes. 10. Keep applying Branch Collapsing, Series Pipe Merging, and Parallel Pipe Merging until you can go no further. 11. Occasionally you will need to do a Smart Pipe Removal, but try to minimize the use of that operation. 12. Answer the questions at the end of the workshop.
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Results Tables
Results Tables Note: You may round your answers. Pipe Removal Action
Pipes Left
Nodes Left
Pressure A-100 (psi)
Pressure A-100 (psi)
System Head Curve PMP-1 (ft)
Base
Fire
Base
Start Remove < 6 in. Remove Compute to check that the model is complete. 2. Close the Calculation Summary and User Notification windows if they come up. 3. Look through the Pipe and Junction FlexTables to make sure that values are reasonable. Note: This system has two pressure zones, an upper one fed by a variable speed pump with no tank and a lower one fed by constant speed pumps and has a tank serving it. 4. Select View > Element Symbology. 5. Expand Pipe. 2
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Getting Started
6. Uncheck Diameter and put a checkmark in Hydraulic Grade (Start).
Note: The upper zone should be red and the lower one blue; like this:
Exercise: Adding pipe velocity color coding 1. Select View > Element Symbology. 2. Right click on Pipe and select New > Color Coding. 3. Set the following on the Color Coding Properties dialog: Field Name:
Velocity
Selection Set: Minimum:
0 ft/s
Maximum:
20 ft/s
Steps:
5
Options:
Color and Size
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
3
Getting Started
4. Click the Initialize
button (third button).
5. Change the Values, Colors and Sizes as shown below: Value
Color
Size
0.1
Gray
1
1.0
Green
2
3.0
Blue
3
5.0
Magenta
4
20.0
Red
5
6. Click Apply and then OK. Exercise: Adding hydrant demand color coding Now set up Hydrant element color coding so that the flowed hydrant for any event will appear very large. 1. Select View > Element Symbology. 2. Right click on Hydrant and select New > Color Coding. 3. Set the following values: Field Name: 4
Demand Developing System Flushing Routines
Copyright © December-2008 Bentley Systems Incorporated
Getting Started
Selection Set: Minimum:
0 gpm
Maximum:
2000 gpm
Steps:
3
Options:
Color and Size
4. Click the Initialize button. 5. Change the Values, Colors and Sizes as shown below: Value
Color
Size
50
Green
1
500
Blue
10
2000
Red
10
6. Click Apply and OK. 7. Fill in the Results Table at the end of the workshop for normal conditions.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
5
Flushing
Flushing This section will walk you through the two different types of Flushing in WaterCAD/GEMS: Conventional and Unidirectional Flushing.
Conventional Flushing Exercise: Creating a selection set for all hydrants in the model In this analysis, you will open all hydrants one at a time (Conventional Flushing). 1. Create a selection set of all hydrants by selecting Edit > Select by Element > Hydrant. 2. Then right click on the drawing pane and select Create Selection Set. 3. Name this selection set All Hydrants.
4. Click OK. Optional Exercise: Viewing the selection set using Network Navigator 1. If you want to view the selection set, you can select View > Network Navigator. 2. On the Network Navigator window, click in the dropdown box at the top and select the All Hydrants selection set.
3. Close out of Network Navigator when you are done. Exercise: Creating the flushing alternative 1. Select Analysis > Alternatives. 6
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
2. Expand Flushing and open the Base Flushing alternative. 3. Set the following: Target Velocity:
3.0 ft/s
Pipe Set:
All Pipes
Note: This means the target velocity will be checked for all pipes in the system. Compare velocities across prior scenarios? Leave unchecked Flowing Emitter Coefficient:
160 gpm/psi^n
Flowing Demand:
0 gpm
Apply Flushing Flow By:
Adding to baseline demand
Report on minimum pressure?
Check the box
Include nodes with pressure less than?
Check the box
Node Pressure Less Than:
30 psi
4. Do not check Include pipes with velocity greater than? because you have already selected All Pipes as the Pipe Set.
5. Select the Conventional tab in the Flushing Alternative dialog. Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
7
Flushing
6. Click the Initialize from Selection Set
button.
7. Select All Hydrants as the Selection Set; these are the nodes to flush.
8. Click OK. Note: You will specify the flushing alternative to use the 4.5 inch outlet on hydrant H-91. 9. Select the Use local? box for Hydrant H-91 and set the Emitter Coefficient to 400 gpm/psi^n.
10. Close the Flushing Alternative and Alternatives dialogs. Exercise: Setting the Calculation Options for Flushing 1. Select Analysis > Calculation Options. 2. With Steady State/EPS Solver selected, click the New button. 3. Name this Calculation Option FlushingCalc.
8
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
4. Double click on FlushingCalc and in the Properties window, set the Calculation Type to Flushing.
5. Close out of the Calculation Options dialog. Exercise: Creating the flushing scenario 1. Open the Scenarios manager by selecting Analysis > Scenarios. 2. Click on the Steady scenario. 3. Click the New button and select Child Scenario. 4. Name the new scenario, Flush–Conv.
5. Open the Flush-Conv scenario and set the Steady State/EPS Solver Calculation Options to Flushing Calc.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
9
Flushing
6. Make Flush–Conv the current scenario by selecting it in the Scenarios manager and clicking the Make Current button. 7. Close the Scenarios manager. Exercise: Computing the Flush-Conv scenario and reviewing results 1. Select Analysis > Compute or click the Compute button. 2. Close the Calculation Summary and User Notification windows if they come up. Exercise: Reviewing conventional flushing results 1. Select View > FlexTables. 2. Open the Flushing Report. 3. Right click on the Maximum Achieved Velocity column heading and select Sort > Sort Descending.
4. Fill in the Results Table at the end of the workshop. 5. Notice the following:
10
P-675 had no velocity because it was a closed zone divide pipe. P-665 had no velocity because it was a dead end pipe with no hydrant
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
TL-107 had marginal velocity because it is a larger pipe with two directional feed P-455 had good velocity P-294 had very high velocity because it was a dead end pipe
6. Close out of the FlexTable windows. Exercise: Color coding pipes based on maximum velocity 1. Select View > Element Symbology. 2. Right click on Pipe and select New > Color Coding. 3. Set the following: Field Name:
Velocity Maximum Achieved
Selection Set: Minimum:
0 ft/s
Maximum:
20 ft/s
Steps:
5
Options:
Color and Size
4. Click the Initialize button. 5. Change the Value, Color and Size as shown below: Value
Color
Size
0.0
Gray
1
1.0
Green
3
3.0
Blue
5
5.0
Magenta
7
20.0
Red
9
6. Set the Above Range Size to 9.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
11
Flushing
7. Click Apply and OK. 8. Back in the Element Symbology dialog, check only Velocity Maximum Achieved. 9. Review the drawing.
12
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
10. Remember to save your file periodically. Exercise: Using the Flushing Results Browser to view individual flushing events 1. Select Analysis > Flushing Results Browser.
2. In the Element Symbology window, check Velocity and uncheck Velocity Maximum Achieved. 3. Make sure that Demand is checked under Element Symbology for Hydrants.
4. Once the Flushing Results Browser is open, click on the various flushing events to see which pipes experienced high velocity during the particular flush. 5. For example, here is the view for Hydrant H-42 which flushes TL-107.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
13
Flushing
Note: The velocities are not very high. 6. Click on the Flushing Event Results
button.
7. Review some of the details for this selected event.
Note: Not a single section of pipe experienced its maximum flushing velocity when this hydrant was opened. Also see that one node reached 0 psi pressure. Flushing this hydrant may not be useful since the pipes around this area were better flushed by H-33. 14
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
8. To review pressures for any event, open the Junction FlexTable. 9. Right click on the Pressure column heading and select Sort > Sort Descending. 10. Most of the table will be N/A because those junctions did not drop below the 30 psi specified. Remember you set 30 psi for Include nodes with pressure less than? Note: The junctions that do drop below 30 psi are mostly on the suction sides of pumps. Figure: Junction FlexTable for Flushing [H-42]
11. Close the Junction FlexTable. 12. Continue to browse around to other flushing events using the browser and see how effective each event was. 13. For example, Flushing H-16 did not flush a large section of pipes because the hydrant was very close to the source. 14. On the other hand, Flushing H-91 flushed a sizable length of pipe because of its location and the fact that the 4.5 inch outlet was used. 15. Close the Flushing Results Browser when you are done.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
15
Flushing
Unidirectional Flushing Pipe TL-107 did not achieve a very high velocity even though it is fairly close to the source because it gets flow equally from both directions and it is a larger pipe. You will need to set up a unidirectional event that will try to force flow from one direction. Exercise: Reviewing TL-107 1. Zoom into TL-107. Note: You would like to feed it from the tank so you will not be limited by the pump curve. 2. Isolating valves ISO-85 and ISO-212 are at the downstream end of this pipe. Exercise: Creating the new flushing alternative 1. Select Analysis > Alternatives. 2. Select the Base Flushing alternative. 3. Click the New button to create a new child alternative. 4. Name the new alternative UDF-107.
5. Open the UDF-107 alternative to open the Flushing Alternative window. 6. Check that the Flushing Criteria tab still has the same entries as before. 7. Select the Unidirectional tab. 8. Click the New button and select Add Flushing Event. 9. Name the event Flush-107.
16
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
10. Click OK. 11. Click in the Element ID field and click the ellipsis (…). 12. On the Select toolbar, click the Find button. 13. In the Find dialog type H-42 in the top field and click the Find
button.
Note: This will select the element for you and bring you back to the Flushing Alternative.
Exercise: Closing the valves at the end of the line 1. On the Unidirectional tab, click the New button and select Add Elements. 2. On the Select toolbar, you can use the Find valves, ISO-85 and ISO-212.
tool as you did above to locate
3. When you have selected the two elements, click the Done Select toolbar to return to the Flushing Alternative dialog.
button on the
4. The Unidirectional tab should look like the one below indicating that H-42 will be flowed while ISO85 and ISO-212 will be closed.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
17
Flushing
5. Select the Flushing Criteria tab and make sure this event appears in the right pane. 6. Check the box for Compare velocities across prior scenarios? so that this result will be added to the others.
7. Close the Flushing Alternative. 8. Save your file. Exercise: Creating the unidirectional flushing scenario 1. Select Analysis > Scenarios. 2. Create a child scenario of Flush-Conv. 3. Name the new scenario Flush UDF-107.
18
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Flushing
4. Open the Flush UDF-107 scenario and change the Flushing alternative to UDF107.
5. Close the Properties dialog and make Flush UDF-107 the current scenario. 6. Compute the Flush UDF-107 scenario. Exercise: Reviewing results with UDF 1. Select View > Zoom > Zoom Extents. 2. Set the Pipe color coding in the Element Symbology dialog to Velocity Maximum Achieved. 3. Look at the color coding for TL-107. 4. Select View > FlexTables and open the Flushing Report. Note: The velocity in TL-107 for this scenario did not increase dramatically, partly because it is fairly far from the source and partly because it is a 12 inch pipe. 5. Make sure the color coding for Pipe is set to Velocity, and then select Analysis > Flushing Results Browser. 6. Look at the velocities associated with this event.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
19
Results Tables
Results Tables Pipe
Velocity (Normal) (ft/s)
Maximum velocity (ft/s) (from Flushing Report)
P-675 P-665 P-455 P-294 TL-107 (Conventional) TL-107 (UDF)
Normal Hydraulic Grade (Scenario Steady)
20
Zone
Pump
Upper
PMP-12
Lower
PMP-1
Discharge HGL (ft)
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. What could have been done to improve flushing?
2. Why did the velocity at P-103 change so much between normal and flushing demands?
3. What could you do to flush the short dead end pipes in the cul-de-sacs without hydrants?
4. Would you expect unidirectional flushing to be beneficial for TL-107? Why?
5. In flushing P-294, the velocity was very high. What warning would you give to operators that would be especially true for this pipe?
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
21
This page left intentionally blank.
Copyright © 2008 Bentley Systems Incorporated
Workshop Review
Answers Pipe
Velocity (normal) (ft/s)
Maximum velocity (ft/s) (from Flushing Report)
P-675
0.0
0.0
P-665
0.0
0.0
P-455
0.05
5.4
P-294
0.04
13.5
TL-107 (Conventional)
0.02
2.3
TL-107 (UDF)
0.02
2.57
Normal Hydraulic Grade (Scenario Steady)
22
Zone
Pump
Discharge HGL (ft)
Upper
PMP-12
1430
Lower
PMP-1
1254
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
1. What could have been done to improve flushing? Turn on stand-by pumps at the sources.
2. Why did the velocity at P-103 change so much between normal and flushing demands? It was a dead end with virtually no demand on normal day.
3. What could you do to flush the short dead end pipes in the cul-de-sacs without hydrants? Install blow offs at end of line.
4. Would you expect unidirectional flushing to be beneficial for TL-107? Why? You would expect that but the impact was marginal because the pipes being closed did not carry much flow to the flowed hydrant during conventional flushing. The main being flushed is 12 in. which is going to be difficult to flush in any case, especially when it is far from the source and head loss between the source and flowed hydrant would be large.
5. In flushing P-294, the velocity was very high. What warning would you give to operators that would be especially true for this pipe? Be very cautious in closing and opening hydrants in these dead end pipes to minimize water hammer.
Developing System Flushing Routines Copyright © December-2008 Bentley Systems Incorporated
23
Geospatial Data Management Basics
Page 16-1
Geospatial Data Management Basics
Overview • Major advances in modeling and data handling in recent years • Model = Software + Data • Enter data once – Use it many times for many purposes
• Fix data errors once
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-2
Historical Development • Input Cards (1940-75) • Input Files (1965 – present) • Graphical User Interfaces (1990 – present) • Database Connection (1995 – present) • GIS Connection (1997 – present) • Transparent integration of GIS (2003 - present) • Interoperability – Multi-Platform Environment – Federated Geospatial Data (2004-present)
Data Centered vs. Model Centered Approach • Different paradigms for modeling • Shift towards data-centered approach DATA CENTERED
MODEL CENTERED Model Input
Model
Analysis
Data Base
Model 2
Model Model Input
CIS
Model Output
Graphics
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-3
Mapping Paradigms • Communication paradigm – paper map is end product • Analytical paradigm – paper map just one view of spatial relationships/data
Types of Computer Data Files • ASCII (text) • Spreadsheets • Databases • CAD files • GIS files • SCADA files • Customer Information Systems • Word processor files • Others
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-4
Computer Aided Design (CAD) • Main function: generate digital drawings • Limited ability to assign attributes to vectors • DWG (AutoCAD), DGN (MicroStation), and DXF (General) file formats
G I S
eographic - mapping, spatial
nformation - database
ystem - hardware, software
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-5
GIS Capabilities • Combines functionality of CAD & databases • Ability to assign attributes to spatial objects • Use – Data storage/retrieval – Attractive/informative maps
“Geospatial” replacing GIS • Open GIS Consortium now • Open Geospatial Consortium • Emphasis on 3-D geometric data • Emphasis on accuracy
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-6
Topological Model • Describes the connectivity/juxtaposition of objects
Arc A knows that it is connected to Arc B Polygon 17 knows it is adjacent to Polygon 332
A
B
332
17
Geospatial Data Formats • Vector, Raster or TIN format • Vector – points – lines – polygons
• Raster – Raster, regular grid – remote sensing data – digital elevation models (DEM)
Raster Grid
• TIN (Triangulated Irregular Network)
TIN
– surface data
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-7
Land Base (Base Map) • Key to successful GIS • Accuracy – depends on most demanding use • Coordinate system – Lat-long – State Plane – UTM (Universal Transverse Mercator)
• Datum • Year
Map Projection
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-8
Common Coordinate Systems in US • UTM Coordinates (Universal Transverse Mercator) • State Plane Coordinate System • Latitude - longitude • NAD 27 or NAD 83 (North American Datums)
State Plane - Which Zone?
• Zones of the State Plane Coordinate System
Good reference: http://www.fgdl.org/tutorials/howto_reproject/Definitions.html
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-9
UTM - Which Zone? Zone 10 Seattle Portland San Francisco
Zone 15 Minneapolis Little Rock
Zone 11 Las Vegas Boise San Diego
Zone 16 Indianapolis Nashville Birmingham
Zone 12 Salt Lake City Phoenix
Zone 17 Charleston (SC and WV) Roanoke Miami
Zone 13 Denver El Paso Albuquerque
Zone 18 Waterbury Wilkes-Barre New York City
Zone 14 Austin Oklahoma City
Zone 19 Boston Bangor
* Some cities are tricky - Los Angeles and New Orleans fall right at boundaries
Hydraulic/Geospatial Model “Integration” • Use each to do what it does best • Hydraulic Model – – – –
Hydraulic calculations Scenario management Design/operation studies Building model specific data
• Geospatial model – Storage and manipulation of input data – Display of results – Interaction with other data sources
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-10
GIS Products • Bentley Products – Microstation (MSTN) w/Geospatial extension (GSX) – Bentley Water/Wastewater (built on MSTN GSX) – www.bentley.com
• ESRI products – Environmental Systems Research Institute – ArcGIS (and related products)
• Other GIS products – – – – –
GRASS Smallworld MapInfo AutoCAD Map GeoMedia (Intergraph)
ESRI Data Models • Coverages – early PC and UNIX Arc/INFO • Shapefiles – ArcView 2.x and 3.x • Geodatabases – ArcGIS 8 and higher
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-11
Utility GIS vs. Model GIS Citywide GIS
Model GIS
?
Model
Model Model GIS
G E M S
eospatial
ngineering odeling ystem
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-12
Analogy
ArcGIS ArcMap
GEMS WaterGEMS
ArcObjects WaterObjects
Key Geospatial Definitions • Feature – individual element or instance of feature class – P-131, PRV-21
• Feature class – stores features represented as points, lines, or polygons, and their properties – Pipe, Valve
• Feature dataset – set of feature classes with a common spatial reference – Scenario Base
• Geodatabase – contains feature classes (may be organized in feature datasets), and tables – Myfile.mdb
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-13
Model Source
Tool
Software
Import
WaterCAD
Manual Data Entry Old WaterCAD EPANET Bentley Water Shapefile Database Spreadsheet CAD Drawing
(sync)
Geodatabase Geometric Network
M O D E L W O R K F L O W
WaterCAD
ModelBuilder
(sync)
WaterGEMS
ModelBuilder
Geodatabase
Map feature class/subtypes to Model elements Create model w/ModelBuilder
Usage data
Geocode meters
(Add details Where needed) Load model w/LoadBuilder
Format Use data
Import elevation w/TRex
Elevation data
Initial conditions Pump curves Controls Diurnal curves Run-able model
Skeletonize
yes
Skelebrator
no Model cleanup Send changes to GIS
Start calibration
Copyright © 2008 Bentley Systems Incorporated
Start modeling
Dec-08
Geospatial Data Management Basics
Page 16-14
What is the best way to Update your Model? • Incorporating system changes • Depends on… – How much model has changed since it was created – How much GIS/CAD has changed since model created – Whether date of map changes is logged in GIS/CAD
• Approaches vary – Update model automatically – Manual updates – Recreate model
Errors in Data Sources Build model from GIS/CAD
GIS/CAD
Model
Correct GIS/CAD when modeler finds errors
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-15
HMI Modeling Data (xxx.wtg.mdb)
Stand Alone (xxx.dwh)
Microstation (xxx.dgn)
AutoCAD (xxx.dwg)
Project Data (xxx.wtg)
ArcGIS (xxx.mdb)
GEMS File Extensions •
mdb GEMS database – GEMS Data Store – modeling data – Geodatabase – topology (in ArcGIS version)
•
wtg – WaterGEMS display info (was wcd)
•
dwh, dgn, dwg – drawing information in stand-alone, Microstation, AutoCAD
•
mdk – backup of mdb
•
bak – backup of most files
•
out – complete results by scenario
•
rpc – scenario messages
•
nrg – energy cost results
•
pv8 – previous version for files upgraded to new
•
xml – used for libraries
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Geospatial Data Management Basics
Page 16-16
Moving Files • xxx.wtg.mdb contains almost everything you need for modeling • Be sure to zip if sending – will compact significantly • Also send xxx.wtg if want to move graphical settings
Version 7 (3) wcd
wcd
Export Presentation Settings
xml Import Presentation Settings
Version 8
wtg
Copyright © 2008 Bentley Systems Incorporated
Pre-version 7 Export GEMS Dataset
mdb
Import
wtg.mdb
Dec-08
Geospatial Data Management Basics
Page 16-17
Opening Older (pre v8) Models • “Open” wcd invokes conversion wizard • But first, use old version (v7) to Export WaterGEMS Presentation Settings (creates XML file) • For mdb file only, use Import>WaterGEMS Database • For older files (earlier than v6), must first convert to v6 or v7, then convert to v8 using the wizard
The End Enter Data Once - use it many times, for many purposes.
Copyright © 2008 Bentley Systems Incorporated
Dec-08
ModelBuilder
Page 17-1
ModelBuilder Building models from Geospatial Data and other sources
Model Sources • • • • • • • •
Access (Jet) Coverages Geodatabases Geometric Networks dBase FoxPro ODBC OLEDB
Copyright © 2008 Bentley Systems Incorporated
• • • • • • • • •
HTML Import HTML Export Lotus Excel Paradox Shapefiles CAD files EPAnet Old WaterCAD
Dec-08
ModelBuilder
Page 17-2
How it Works
Source File e.g. GIS, Excel
Target File (GEMS Data Store) 15 mins 30 mins 6 months??
The devil is in the details
ModelBuilder V8i GIS Day 1
GIS Day n
Model In synch Day 1
Not in synch
Model Day n
GIS Model Day n In synch Day n again
Copyright © 2008 Bentley Systems Incorporated
Dec-08
ModelBuilder
Page 17-3
GIS Features to Model Elements Gate Valve
T-fitting
45 bend Reducer Hydrant Lateral
New Pipe
X -fitting
GIS View
Gate Valve
Model after ModelBuilder
Model after Skelebrator
Earlier Versions Version 7 (3) wcd
Update wcd
Export Presentation Settings xml Import Presentation Settings
Version 8
wtg
Copyright © 2008 Bentley Systems Incorporated
Pre-version 7 Export GEMS Dataset
mdb
Import
wtg.mdb
Dec-08
ModelBuilder
Page 17-4
Each Table in Source File Must Map to one GEMS Element Source File Tables Tee’s
Target File Tables Isolation Valves
Gate Valves
Pressure Junction Air Release Valves*
Air Releases
PRVs
PRVs
Pumps
Pumps
Pipe?
Check Valves
Check Valves*
* Service Pack 3 and above only – 8.9.400.34+
If multiple element types, must first put in separate tables before Builder Label
Type
Elev
J-2
Junc
680
PRV-1
PRV
685
J-12
Junc
623
PMP-1
Pump
650
J-100
Junc
610
PSV-1
PSV
587
Copyright © 2008 Bentley Systems Incorporated
Junction Table
PRV Table
Pump Table
PSV Table
Dec-08
ModelBuilder
Page 17-5
Exception – Geodatabases ModelBuilder recognizes ArcGIS subtypes if designated as such Label
Name
Subtype
J-2
Junction
1
PRV-3
PRV
2
J-3
Junction
1
PMP-1
Pump
3
PMP-2
Pump
3
No need to break table based on type
GIS Feature GEMS Element Bend, fitting, negligible loss
Pressure junction
Bend, fitting, significant loss
GPV, TCV or minor loss on adjacent pipe
Isolating valve, used for criticality analysis
Isolating valve (version 8.9.165.12 and greater)
Isolating valve, always open, negligible loss
Pressure junction
Isolating valve, always open, significant loss
GPV, TCV or minor loss on adjacent pipe GPV
Isolating valve, normally closed
Closed valve
Air release valve
Pressure junction
Air release valve
Air release valve (version 8.9.400.34 and greater)
Copyright © 2008 Bentley Systems Incorporated
Dec-08
ModelBuilder
Page 17-6
GIS Feature GEMS Element (2) Customer/lateral
Pressure junction
Hydrant + lateral
Hydrant with lateral as property, hydrant + lateral, or just a hydrant
Check valve in-system
Property of adjacent pipe
Check valve at pump
Part of pump
System water meter
GPV, TCV or minor loss on adjacent pipe
Pump control valve
Pressure junction
Reducer
Pressure junction w/ different diameter each side
Change in material
Pressure junction
Must be Common Key/Label between Source and Target Label
D
C
P-134
Label
Diam
Rough
P-134
Source
Copyright © 2008 Bentley Systems Incorporated
Target
Dec-08
ModelBuilder
Page 17-7
Must Identify Relationship between Source and Target Attributes Label
D
C
P-134
Label
Diam
Rough
P-134
Source
Target
When done, data will be copied Label
D
C
Label
Diam
Rough
P-1
0.5
130
P-1
6
130
P-17
0.5
110
P-17
6
110
P-100
0.5
130
P-100
6
130
P-134
0.667
130
P-134
8
130
P-220
0.667
110
P-220
8
110
P-231
0.5
90
P-231
6
90
Source
Copyright © 2008 Bentley Systems Incorporated
Target
Dec-08
ModelBuilder
Page 17-8
Considerations • Not all fields from source file need be copied (e.g. installation date) • Not all attributes in target file need to come through ModelBuilder (e.g. color coding) • x,y coordinates automatically come in from Shapefiles/geodatabases/CAD drawings • System Demands may be better imported using LoadBuilder • Elevations are best imported from DEMs using TerrainExtractor (TRex)
Pipe Bends • Vertices captured in Geodatabases, Geometric Networks, Coverages and Shapefiles • Only straight pipe import from databases and spreadsheets
Copyright © 2008 Bentley Systems Incorporated
Dec-08
ModelBuilder
Page 17-9
Things you cannot import with ModelBuilder • Composite demand • Libraries • GeoGrapher setup • Cost data • Darwin parameters • Color coding • With V8, can import patterns, pump curves…
Types of Connectivity • Explicit –start – stop nodes specified in source file • Implicit – pipes are assigned to start – stop nodes based – on nearest node if nodes exist – pipe end coordinates if nodes don’t exist
J-5
P-3
P-3 J-6
J-5
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Connectivity Issues Pipes without end nodes Pipes that do not connect but should
Pipes that appear to connect but are not
Pipes that cross without junctions
Resolving Connectivity Problems • Add end nodes to pipes without end nodes • Snap ends of pipes to single node if within (user specified) tolerance Tolerance
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ModelBuilder’s Connectivity Logic Do pipes have end points in pipe data?
Yes
No
Explicit connectivity: node data used for ends
Implicit Connectivity: are there nodes in data with x-y values?
Create nodes at end of pipes?
Import failure
Yes
Establish connectivity w/spatial data?
No
No
No
Specify node field to use as start/stop
No
Yes (Set tolerance) In tolerance?
Yes Nodes created
Yes Pipe connects to node
Complex Edges and Geometric Networks Geometric Network
Complex Edge
Geodatabase Feature Class
Copyright © 2008 Bentley Systems Incorporated
3 Pipes - 4 Nodes
1 Pipe – 2 Nodes
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Network Navigator • Finds possible problems caused by – – – –
Nodes in close proximity to other nodes Nodes in close proximity to pipes Orphaned nodes Elements with messages from previous run
Drawing Cleanup • View > Network Navigator • Useful for ModelBuilder • Manually review one-by-one and make changes – Tolerance for drawing review should be greater than for spatial connectivity
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Direction Matters (sometimes) • Must specify “downstream edge” (pipe) for – Pumps – Control valves (PRV, FCV)
• Check valves – Should indicate which pipes have valves – Manually check each check valve
GIS/CAD Building Tips • Snap all pipe ends to something! • Make other valves point features or isolating elements • Element labeling conventions important • Put hydrant laterals & service lines in separate feature class, layer, or level from pipes, and – maintain hydrant lateral info as part of hydrant properties
• Put tanks, pumps, valves, etc. in their own feature classes, layer/level, or use Subtypes)
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The End The devil’s in the details.
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Copyright © 2008 Bentley Systems Incorporated
Automating Model Building using ModelBuilder Workshop Overview In this workshop, you will use shapefiles created in ArcGIS to construct a model and run it. You will use various shapefiles in conjunction with WaterGEMS ModelBuilder, and use WaterGEMS to run the model.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Geospatial Data Overview
Workshop Objectives After completing this workshop, you will be able to:
Use ModelBuilder to build a model from Shapefiles
Use Network Navigator to review a model’s connectivity
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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ModelBuilder
ModelBuilder This section will walk you through the steps of creating a model from Shapefiles with the use of ModelBuilder. Exercise: Opening WaterGEMS and creating a new project 1. Start WaterGEMS V8i. 2. On the Welcome dialog, click Create New Project or if that window is not open select File > New from the WaterGEMS main toolbar. Exercise: Starting ModelBuilder 1. Start ModelBuilder by clicking on the ModelBuilder Tools > ModelBuilder.
button or by selecting
The empty ModelBuilder dialog will appear. Note: ModelBuilder itself is a wizard, but the settings from the wizard dialogs are saved in this manager for future use and editing.
2. Click the New button to kick off the ModelBuilder Wizard. Exercise: Step 1 –Specify Your Data Source 1. In the Select a Data Source Type dropdown menu select Shapefiles. 2. Click the Browse button next to Select your Data Source. 3. Navigate to C:\Program Files\Bentley\WaterDistribution\Starter\ModelBuilder. 4. Hold down the Ctrl key on your keyboard and then select the following three shapefiles: Pipes_2.shp, Junctions_2.shp, and Tanks_2.shp. 5. Click Open to send this selection to ModelBuilder. This adds the three feature classes to the left pane of the wizard. 2
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
Note: Each of the feature classes listed has a checkbox next to it that you can use to exclude it from processing by the wizard. 6. Check the Show Preview box and you will see the type of data available with each table in the right pane. 7. Select Tanks-1 and note that the following fields: Elevation_, Elevation1, and Elevatio_2 have no data; however the field Elevatio_1 has numeric data.
8. Select the Next button to advance to the Specify Spatial and Connectivity Options dialog. Exercise: Step 2 – Specify Spatial Options 1. Specify ft as the Coordinate Unit of the data. 2. Make sure the Create nodes if none found at pipe endpoint and Establish connectivity using spatial data fields are NOT checked.
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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ModelBuilder
3. Click Next. Exercise: Step 3 – Specify element create/remove/update options 1. Leave the defaults on this step as is.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
2. Click Next. Exercise: Step 4 – Specify additional options 3. Leave the defaults on this step as they are.
Note: If you were importing this data into an existing model you can choose to import the data into the current scenario or you can create a new child scenario. New scenario and alternatives will be automatically labeled Created by ModelBuilder followed by the date and time when they were created. If there is no data change for a particular alternative, no child alternative will be created in that case. 4. Click Next. Exercise: Step 5 – Specify Field Mappings for each table Now you are in the section of ModelBuilder where you connect attribute fields from your Shapefiles to WaterGEMS element properties. 1. Click on Junctions_2 in the left pane and select the Settings tab in the right. 2. Select Junction from the Table Type menu. Note: This gives you access to all the fields in your source file.
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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ModelBuilder
3. Set Key Fields to Label. 4. Leave the X Field and Y Field set to since the coordinates will automatically be transferred from the data file. 5. Under the Field column, click on Elevation, then from the Attribute menu select Elevation and ft from the Unit menu.
6. Select Pipes_2 in the left pane and select Pipe as the Table Type. 7. For the Key Fields, select Label from the menu. 8. Leave the Start and Stop fields to as these particular fields are related to the Spatial Connectivity option in a previous window. 9. Select Diameter under the Field column and select Diameter from the Attribute menu. 10. Select in from the Unit menu.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
11. Select Tanks_2 in the left pane and select Tank as the Table Type on the right. 12. Select Label from the menu under the Key Fields. 13. Select Diameter in the Field column and select Diameter from the Attribute menu. 14. Make sure you select ft from the Unit menu. 15. Select Elevatio_1 in the Field column and select Elevation (Base) from the Attribute menu, and ft in the Unit menu.
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ModelBuilder
16. Click Next when done. Exercise: Step 6 – Create Model Now? 1. On the next screen, select Yes to build the model and leave the other two boxes checked as well.
2. Click Finish. 3. After ModelBuilder has run, the ModelBuilder Summary dialog will state that it was unable to create pipes due to missing topology. 8
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
4. Select the Messages tab and you will see that the pipes could not find their start and stop nodes.
5. Close the ModelBuilder Summary. Exercise: Fixing the spatial data issue To resolve this issue, we will go back into ModelBuilder and let it resolve the topology based on the proximity of nodes to the pipe ends. Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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ModelBuilder
1. In the ModelBuilder dialog, select the Duplicate existing connection.
button to make a copy of the
2. With the copy, ModelBuilder(1) highlighted, select the Edit into the ModelBuilder Wizard.
button to go back
3. Click Next since the Data Source fields are already filled in. Note: This is where you implicitly tell ModelBuilder to establish connectivity from the data source itself. If this box is unchecked, then you would need to explicitly specify the connectivity in the Field Mappings: Pipes – Start/Stop fields. 4. On the Specify Spatial and Connectivity Options dialog, check the box for Create nodes if none found at pipe endpoint. 5. Check the box for Establish connectivity using spatial data and set the Tolerance to 0.1 ft.
6. Click Next until you get to the Create Model Now? dialog. 7. Select Yes to build the model now. 8. Click Finish. 10
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
This time 519 pressure junctions, 657 pressure pipes, and 2 tanks were updated.
9. Close the ModelBuilder Summary and close ModelBuilder. 10. Click Yes to the following dialog:
Exercise: Reviewing the model 1. Back on the WaterGEMS screen; select View > Zoom > Zoom Extents to view the newly built model.
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ModelBuilder
2. Review the model information that has been created with the ModelBuilder. 3. Select View > Selection Sets.
Note: You will see that two selection sets have been created. 4. Highlight one of the sets and click the Select In Drawing
button.
5. Close the Selection Sets dialog when you are done and select Report > Element Tables > Junction. Note: You should see the elevations that were mapped from source file. 6. Sort the Elevation column in Ascending order. You will see the eight nodes that were created by ModelBuilder, and do not yet have elevations.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
ModelBuilder
7. Close the Junction table and select Report > Element Tables > Pipe.
8. Close the Pipe table and select Report > Element Tables > Tank. Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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ModelBuilder
Note: If you review other tables, such as Reservoirs, or PRVs, they will be empty because these elements were not present in the source file.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Inputting Model Data
Inputting Model Data Now that we have the model built we would like to compute the model, however some additional information needs to be entered. Exercise: Saving your model 1. Select File > Save As. 2. Name your file ModelBuilder.wtg. If you ran the model now, it would not run because you do not have initial water surface elevations in the tanks. You will need to set them. Exercise: Entering tank data 1. Select the FlexTables
button or select View > FlexTables.
2. Double click on Tank Table. 3. Enter the following for both tanks: Minimum Elevation (ft)
1460
Initial Elevation (ft)
1475
Maximum Elevation (ft)
1480
4. Close out of the Tank FlexTable. Exercise: Entering junction demands You recall from the ModelBuilder procedure that the only data assigned to model junction nodes were elevations; so there are no demands on the model. 1. Select Tools > Demand Control Center. Note: If you receive a warning message regarding cancel and undo, click Yes.
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Inputting Model Data
2. Click on the down arrow next to the New button, and select Initialize Demands for All Elements.
3. Right click the Demand (Base) column heading and select Global Edit. 4. Set all demands to 2 gpm.
5. Click OK.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Inputting Model Data
6. Click Close to exit the Demand Control Center. Exercise: Computing the model and reviewing results 1. Select the Compute button on the main window to run the model. When the run is complete, the Calculation Summary will be generated. 2. Close out of the Calculation Summary. 3. Select the FlexTables button, and double click Junction Table to open it. 4. Review the Pressure column for the junctions. 5. Sort the Pressure column in Ascending order. You will see one node A-311 with low pressure because of its elevation.
6. Click Zoom To
button to locate A-311 on the drawing.
You will see that A-311 is near the Hillside tank.
7. Restore the Junction FlexTable and sort Pressure column in Descending order.
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
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Inputting Model Data
Note: You will see a few nodes with very high pressures reported because they did not have elevations assigned. These are eight the nodes created during the ModelBuilder process. 8. Complete the node elevation data by entering the missing elevations using the following values: Warning: Make sure to match the correct elevation up with the correct junction. Label
Elevation (ft)
J-1
1301
J-2
1302
J-3
1303
J-4
1304
J-5
1305
J-6
1306
J-7
1307
J-8
1308
9. Minimize the Junction FlexTable and Compute the model again. 10. Close the Calculation Summary, restore the Junction FlexTable.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Inputting Model Data
11. Fill the Run values in the table for question one at the end of the workshop.
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Network Navigator
Network Navigator In this section you will use a few of the Network Navigator tools to review the data in your newly built model from ModelBuilder. Exercise: Finding pipe split candidates 1. Select View > Network Navigator.
First you need to look for pipes that are not connected to nodes. 2. Click the Select
button and select Network Review > Pipe Split Candidates.
3. Set the Tolerance to 20 ft.
4. Click OK. Note: You will find four nodes that meet this criterion.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Network Navigator
5. Adjust the Zoom to 75%, click on A-663 and select the Zoom To
button.
6. Do this for each of the four nodes moving the Network Navigator dialog to the side to view the nodes.
With each case, you will see situations where you may need to go back to the original As-Built drawings to decide if connections really exist in the field. If there is an error, you need to decide if you want to correct it only in the model or in the GIS, and then re-import the model. Exercise: Finding nodes in close proximity button in Network Navigator and select Network Review > 1. Click the Select Nodes in Close Proximity. 2. Set the Tolerance to 30 ft and click OK.
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Network Navigator
Note: You will find one node that meets this criterion.
3. Again, you can select the Zoom To button to review the situation.
Note: If two nodes are in close proximity, only one of the nodes is listed in the Network Navigator window. Without additional information it is difficult to determine if these nodes are connected. 22
Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Network Navigator
4. If necessary, move the Network Navigator window so you can see the drawing tools. 5. On the main screen, select the Junction the drawing.
drawing tool, and add a junction to
6. Label this junction J-9.
7. In Network Navigator, click Select > Network Review > Orphaned Nodes. 8. J-9 is the only junction you should see in the list.
9. Close out of Network Navigator. 10. Delete J-9 by right clicking on it and selecting Delete. 11. Save your file and answer the questions that follow. Note: You may need to re-run the model to generate results.
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Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Questions 1. What was the pressure (psi) at the following nodes? Node
Run Values (Pressure psi)
A-26 A-162 J-8
2. There were some fields in the data file that were not mapped to an attribute in WaterGEMS. Why was this the case?
3. The data could have been exported to a standard MS Access file and then imported into WaterGEMS. Why was this not a good idea?
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
4. Instead of entering tank level information in WaterGEMS Modeler, how else could you have brought that data into the model?
5. Explain the difference in the Tolerance specified in the ModelBuilder. Specify Spatial Options dialog and the Tolerance specified in Network Navigator. In general which should be lower?
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Workshop Review
Answers 1. What was the pressure (psi) at the following nodes? Node
Run Values (Pressure psi)
A-26
38
A-162
72
J-8
72
2. There were some fields in the data file that were not mapped to an attribute in WaterGEMS. Why was this the case? These fields were not needed in WaterGEMS and did not have a corresponding attribute.
3. The data could have been exported to a standard MS Access file and then imported into WaterGEMS. Why was this not a good idea? Importing the feature classes directly into WaterGEMS enabled bends, (x, y) coordinates, and topology to be automatically imported (preserved).
4. Instead of entering tank level information in WaterGEMS Modeler, how else could you have brought that data into the model? You could have created fields in your source file for tank elevations and used ModelBuilder to bring in the data.
5. Explain the difference in the Tolerance specified in the ModelBuilder Specify Spatial Options dialog and the Tolerance specified in Network Navigator. In general which should be lower? In ModelBuilder, if the tolerance is met, the nodes are merged automatically, while in Drawing Review, if the tolerance is met, the user is given a chance to edit the nodes. As such, the ModelBuilder tolerances should be set finer (Drawing Review larger). Drawing review will allow you to double-check that other connections were not missed because of too small a value in ModelBuilder.
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Automating Model Building using ModelBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
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LoadBuilder Assigning Demand Data to Nodes
Need for LoadBuilder • Import demands with ModelBuilder if demand assigned to nodes • Assigning demands to nodes is the difficult step • Meter records not kept by node • Water use data in many different formats (8 “methods” available in LoadBuilder)
Copyright © 2008 Bentley Systems Incorporated
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Flow Data Formats • Individual customer meter flows • Meter route flows • Pressure zone flows • Population / unit demands – 300 people x 200 gpd/capita
• Land use / unit demands – 5 acres light industrial x 800 gpd/acre
Types of Flow Data • Customer billing data (bottom up) – – – –
Accurate and high resolution Only collected on billing cycle Time resolution not better than monthly Does not include unaccounted-for water
• System metering data (top down) – Coarse spatial resolution – Good temporal resolution with SCADA – Includes unaccounted-for water
• Must be – Geodatabases – Shapefiles
Copyright © 2008 Bentley Systems Incorporated
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Types of Import Point Data to Node
Polygon Flow Data to Node
Polygon Land Use/Population Data to Node Unit Loading Table
Point Data
8 in. 36 in.
Nearest Node
Nearest Pipe
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Point Data 2
Points in Polygon
CIS Meter Data Issues • GeoCoding – must have x,y coordinate for each meter (address matching - TIGER) • Account for bad reads, manual corrections • All meters are not read on same day • Must select averaging period – Previous billing period – Previous year
• Compatibility issues (Unix, AS 400)
Copyright © 2008 Bentley Systems Incorporated
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Raw Billing Data Read Date
Days in Cycle
6 Jun 03
Read, gal
Gallons billed
Bill, $
Demand, gpd
326578
7 Jul 03
32
340114
13536
43.31
4 Aug 03
28
353554
13440
43.01
6 Sep 03
33
368602
15048
48.15
Gallons billed
Bill, $
Demand, gpd
Calculated Demand Read Date
Days in Cycle
6 Jun 03
Read, gal
326578
7 Jul 03
32
340114
13536
43.31
423
4 Aug 03
28
353554
13440
43.01
480
6 Sep 03
33
368602
15048
48.15
456
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Page 18-6
Correcting Metered Data for Unaccounted-for Water • Production = Billed + UAF • UAF is known % of production (u) • Production = Billed + u Production • Production = Billed/(1 – u) • If u = 20% (0.2), then Production = Billed/0.8
Area Flow Data Sources • Meter route • System meter service area – Pressure zone – Water loss district
• Entire service area
Copyright © 2008 Bentley Systems Incorporated
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Area Water Use Data Equal Flow Distribution
100 gpm
100 gpm/5 nodes = 20 gpm per node
Area Water Use Data Proportional by Area
100 gpm
25% of area x 100 gpm = 25 gpm
Differs for each node ∑% = 100
Copyright © 2008 Bentley Systems Incorporated
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LoadBuilder
Page 18-8
Area Water Use Data Proportional By Population 30 people/200 in area = 15% 15% x 100 gpm = 15 gpm
100 gpm
Using Polygons
Node Polygons
Flow Polygons 150
80
120 200
Node Demand = 20%(150)+40%(120)+30%(80)+15%(200)=132
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Population/Land Use Data • Difficult to directly project flow • Usually project population/land use • Sources of data – – – – –
Census Tracts Traffic Serial Zones Planning Districts Precincts/wards Any kind of polygon
Population/Land Use Methods • Overlay polygons on node service polygons • Need – Node service polygons – Population/land use polygons – Demand density (Unit demand) table
• Check that sum of the parts equal the whole
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Demand Density • Population – Gal/capita/day by type (e.g. large lot) – Gal/unit/day by type (e.g. per bed) – Population equivalent
• Land Use – Gal/acre/day by type (e.g. light industrial)
• Some literature values available • Need to customize for your system
Node Service Area Polygons • Nodes (points) must be converted to areas (polygons) • Can manually draw polygons • Thiessen polygon generation automated • Formed by bisecting lines connecting nodes
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Thiessen Polygon Generation 1
2
3
4
LoadBuilder Results • Create a Child Demand Alternative • Override an existing Demand Alternative • Append to an existing Demand Alternative
Copyright © 2008 Bentley Systems Incorporated
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Other Options • Assign multiplier by demand type • Assign pattern by demand type • Can save template
The End Import demands from a wide variety of data sources
Copyright © 2008 Bentley Systems Incorporated
Dec-08
Automating Demand Allocation using LoadBuilder Workshop Overview In this workshop, you will import model demand data from two different kinds of data sources. The first raw data source you will use is customer meter data. The second data source you will use is population data assigned to polygons. Unaccounted-for water is 15%.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Geospatial Data Overview
Workshop Objectives After completing this workshop, you will be able to:
Apply demand data using customer meter data
Apply demand data using population data
Create service area polygons using Thiessen Polygon Generator
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
1
Getting Started
Getting Started You have a basic water model that has been created, but it does not have demands loaded onto it. Information relating to metered customer demands is contained in a shapefile Meters.shp. Population data is provided in a shapefile called PopulationCensus.shp. Exercise: Opening WaterGEMS and the starter file 1. Start WaterCAD V8i or WaterGEMS V8i. 2. On the Welcome dialog click Open Existing Project or if that window does not come up select File > Open. 3. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\LoadBuilder and open the LoadBuilder_Start.wtg file.
Reviewing and Entering Data Exercise: Importing a background layer 1. Select View > Background Layers to open the Background Layers manager. 2. Click the New button and select New File.
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Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
Getting Started
3. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\LoadBuilder and select the Meters.shp file to Open. 4. On the Shapefile Properties dialog box change the Line Color to a color other than black.
5. Click OK to complete the import.
Exercise: Entering element elevation data 1. Select View > Find Element.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
2. In the Properties dialog box, type PMP-1 into the search bar and click the Find button. Note: This will zoom to the element and open its properties. 3. Enter 2670 for the Elevation (ft). 4. Enter the following element elevation data in the same manner or use the Junction FlexTable to finish: Element
Elevation (ft)
J-104
2600
J-108
2670
J-112
2600
J-113
2600
Exercise: Reviewing the existing demand alternative 1. Select Analysis > Alternatives. 2. Expand the Demand alternative category. Note: Note that the only demand alternative is the default, Base-Average Daily.
Exercise: Computing the model and reviewing the results 1. Select Analysis > Compute or click the Compute to calculate the Base scenario.
button from the main toolbar
2. Close the Calculation Summary dialog and open the Junction FlexTable. 3. Review the demands and pressures. Note: The FlexTable shows zero demands and high pressures; this is because there is no demand data and the pump is running near shutoff head. 4. Close the Junction FlexTable.
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Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
LoadBuilder This section is going to walk you through applying customer meter data using the Nearest Node and Nearest Pipe Methods. You will then apply demands based upon population data assigned to polygons. Exercise: Opening LoadBuilder 1. Activate LoadBuilder by clicking the LoadBuilder > LoadBuilder.
button or by selecting Tools
Nearest Node Method Exercise: Applying loads using the Nearest Node Method 1. Start the LoadBuilder Wizard, by clicking the New button. 2. On the Available LoadBuilder Methods dialog, select the Allocation radio button and click Nearest Node.
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LoadBuilder
3. Select Next to continue. 4. Click the ellipsis (…) for Node Layer to open the Select a Layer dialog.
5. Click on Junction\All Elements and click Select. 6. Use the dropdown menu to set the Node ID Field to ElementID. 7. Click the ellipsis (…) button for Billing Meter Layer. 8. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\LoadBuilder, select the Meters.shp file and select Open. You will receive this message:
9. Click OK. 10. Set the Load Type Field to , the Usage Field to DEMAND in gpm and check the Use Previous Run box.
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Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
11. Click Next to continue. The Calculation Summary will be generated.
12. Note that the total load associated with the meter records is 1088.6 gpm. Note: If the calculation fails and gives you a message, click Back and uncheck the Use Previous Run box and try again. This time the calculation might take longer. These records are based on customer meter readings, so they do not include unaccounted-for water. We need to apply a factor to provide for UAF water. Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
Note: The unaccounted for water in the system is 15%, so multiply the demands globally by 1.176 [which is = 1/ (1-0.15)] to correct for unaccounted-for water. 13. Set the Global Multiplier to 1.176.
14. Select Next to continue. You do not have to change anything on the Results Preview dialog, just note that there are no inflow nodes.
15. Select Next to continue. 16. On the Completing the LoadBuild Process dialog, enter NearNode1 for the Label. 17. Select the New Alternative radio button and enter a name of NearNode. 8
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
18. Set the Parent Alternative to Base-Average Daily.
19. Click Finish. 20. Confirm that 102 demands were successfully exported.
21. Close the LoadBuilder Run Summary and LoadBuilder dialogs. Exercise: Creating the NearNode Scenario 1. Before you create the scenario select Analysis > Alternatives. 2. Expand the Demand alternative category and make sure there is a new child alternative to Base-Average Daily called NearNode.
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LoadBuilder
3. Close the Alternatives manager and select Analysis > Scenarios. 4. Click the New button and select Child Scenario. 5. Name the new scenario Load_at_Node.
6. Edit the properties of Scenario: Load_at_Node and select NearNode as the Demand Alternative.
7. Close the Scenarios manager. Exercise: Computing and reviewing the results of the NearNode Scenario 1. Make Load_at_Node the active scenario. 2. Compute the model using Analysis > Compute or the Compute button. 3. When the Calculation Summary is displayed note the value listed for Flow Demanded (gpm). 4. Compare this demand total (1280.19 gpm) with the metered total (1088.6 gpm); the difference is due to the unaccounted - for allowance.
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Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
5. Close the Calculation Summary. 6. Open the Junction FlexTable and review the demands that were input with LoadBuilder. 7. Record the pressures in the table at the end of the workshop.
Nearest Pipe Method Next you will use the same metered data but this time you will use the Nearest Pipe Method. Exercise: Applying loads using the Nearest Pipe Method 1. Activate LoadBuilder by clicking the LoadBuilder button or by selecting Tools > LoadBuilder.
2. Click the New button to start the LoadBuilder Wizard. 3. Select the Allocation radio button, scroll down and select Nearest Pipe.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
4. Click Next. 5. Set the following for the Model Pipes Data section: Pipe Layer
Pipe\All Elements
Pipe ID Field:
ElementID
Load Assignment:
Distance Weighted
6. Set the following for the Model Node Layer section: Node Layer
Junction\All Elements
Node ID Field:
ElementID
Use Previous Run:
Check the box
7. Click the ellipsis (…) for Billing Meter Layer and browse to the location of the Meters.shp file like we did earlier. 8. Set the following:
12
Load Type Field:
Billing Meter ID Field:
OBJECTID
Polyline Distribution:
Equal Distribution
Usage Field:
DEMAND gpm Automating Demand Allocation using LoadBuilder
Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
9. Click Next to continue. Note: The base metered consumption should be 1088.6 gpm again. 10. As you did in the previous run, set the Global Multiplier to 1.176.
11. Click Next to continue. Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
Your Results Preview should look like the one below:
12. Click Next to continue. 13. Enter NearestPipe for the Label. 14. Select the New Alternative radio button and name the new alternative NearPipe. 15. Select Base-Average Daily as its Parent Alternative.
16. Click Finish. You should see that 102 demands were exported successfully. 14
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
17. Close the LoadBuilder Summary and close LoadBuilder. Exercise: Creating the NearPipe Scenario and computing the model 1. Select Analysis > Alternatives. 2. Expand the Demand alternative category. You should see the new alternative, NearPipe, as a child to Base-Average Daily.
3. Select Analysis > Scenarios and create another child from the Base Scenario. 4. Name the new scenario Load_at_Pipe.
5. Edit the properties of Load_at_Pipe and change the Demand Alternative to NearPipe. 6. Close the Scenarios manager and make Load_at_Pipe the active scenario. 7. Click Compute to run the scenario.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
8. On the Calculation Summary, note the Flow Demanded relative to the metered consumption and UAF percentage.
9. Close the Calculation Summary. 10. Go to the Junction FlexTable and review the demands that were input with LoadBuilder. 11. Record the pressures in the table at the end of the workshop.
Thiessen Polygon Generator In the next part of the exercise, you will use population data provided to you in a shapefile called PopulationCensus.shp. Before you can use Population data, you need to construct service area polygons around your nodes. This can be done using the Thiessen Polygon Generator. Exercise: Creating Thiessen Polygons 1. Click the Thiessen Polygon
button or select Tools > Thiessen Polygon.
2. Select the Node Layer radio button, and then click on the ellipsis (…). 3. Select Junction\All Elements as your Node Layer.
16
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
4. Click Next. 5. Select the Buffering Percentage radio button and enter 10 as the percentage. Note: Do not enter a Polygon boundary layer.
6. Click Next. 7. Click on the ellipsis (…) for Output file. 8. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\LoadBuilder, enter a file name of Tpoly and click Save.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
9. Click Finish. 10. When the processing is complete you will be returned to the main WaterGEMS window. Exercise: Adding the Tpoly Shapefile as a background layer 1. Select View > Background Layers. 2. Click the New button and select New File. 3. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\LoadBuilder and select the Tpoly.shp file. 4. On the Shapefile Properties dialog make sure the Fill Figure box is unchecked. Note: You can change the Line Color if you would like.
5. Click OK. 18
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
6. Turn off the Meters.shp background layer by removing the check mark from its box.
This gives you an idea of the relationship between the polygons used for service junctions and those for the population data.
Load Estimation by Population Exercise: Applying loads by population 1. Open the LoadBuilder tool once again. 2. Click the New button to start the LoadBuilder Wizard. 3. Select the Projection radio button and select Load Estimation by Population.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
4. Click Next. 5. Click the ellipsis (…) button for Service Area Layer. 6. Browse to the Tpoly.shp file we just created and select it. 7. Set the Node ID Field to ElementID. 8. Click the ellipsis (…) for Population Layer and browse to the LoadBuilder folder to select the PopulationCensus.shp file. 9. Set the Population Density Type Field to Type and set the Population Density Field to Density, with units of pop/acre. 10. In the Demand Densities per Capita table, enter the following:
20
Demand Type
Load Density (gpd/capita)
R1
98
C
20
R2
82
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
LoadBuilder
11. Click Next. 12. Enter 1.176 for the Global Multiplier; in order to account for the 15 % - unaccounted water.
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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LoadBuilder
13. Click Next. 14. Review the Results and click Next.
15. Enter the Label as Pop_LandUse. 16. Select the New Alternative radio button and add Pop_LandUse for the name. 17. Select Base-Average Daily as the Parent Alternative.
18. Click Finish. 19. Close the LoadBuilder Summary and then go back into the WaterGEMS modeler to view the new demand data and create a new scenario that incorporates it. 20. Compute the scenario, add the answers to the table and answer the questions. 22
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned. Node
Location
C_028
North
D1_078
East
D1_091
Near Source
Near Node Pressure (psi)
Near Pipe Pressure (psi)
Population & Land Use Pressure (psi)
Questions 1. How would you get metering data for a model run for demands in the year 2040?
2. Why did small changes in demand make big differences in pressure in this model?
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
Answers Node
Location
Near Node Pressure (psi)
Near Pipe Pressure (psi)
Population & Land Use Pressure (psi)
C_028
North
85.3
85.2
105.7
D1_078
East
55.1
55.1
75.5
D1_091
Near Source
87.5
87.5
107.7
1. How would you get metering data for a model run for demands in the year 2040? You do not have a good source of meter data, so you need to use another source such as population or land use to drive demands.
2. Why did small changes in demand make big differences in pressure in this model? This was a dead end system with a pump and no tank. Therefore any change in demand affected not only head loss but the operating point on the pump curve.
24
Automating Demand Allocation using LoadBuilder Copyright © December-2008 Bentley Systems Incorporated
TRex
Page 19-1
TRex Terrain Extraction for Model Building
Sources for Elevation Data • Surveying • GPS • Altimeter readings • As-builts • Vector (Contours) • Manual input from topo maps • Digital Elevation Models (DEM)
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TRex
Page 19-2
Digital Elevation Model Formats • Raster (grid) – One value per cell – Available from USGS – Large files
• TIN (Triangulated irregular networks) – Store data at vertices – Interpolate between values – Usually smaller files than raster
• WaterGEMS inside ArcGIS – ArcToolbox can convert most elevation formats
USGS DEMs • Two Options to acquire 1:24,000-Scale USGSDEM data • OPTION 1 – USGS – Original DEMs - Tiled – – – –
UTM NAD 27/83 (usually) 30 m grid spacing on 7.5 minute quad Accuracy +/-7 m RMSE or 1/3 contour interval Stored as .GZ file which is actually several compressed files – File in SDTS Format (TREX can read USGS-SDTS directly)
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Dec-08
TRex
Page 19-3
USGS DEMs • OPTION 2 – USGS – Seamless Data – National Elevation Datasets (NED) – Interactive Web Download based on a map – Available elevation resolution • 1 Arc Second (~ 30 m spacing) • 1/3 Arc Second (~ 10 m spacing) – 70% US Coverage • 1/9 Arc Second (~ 3 m spacing) – minimal coverage
– Geographic Projection – mostly on NAD 83 – Data Formats – ArcGRID(ESRI), BIL, GeoTIFF
Data Specifications USGS- 7.5” Tiled DEM OPTION 1
NED Seamless OPTION 2
Native Scale
1:24,000
1:24,000
Projection
UTM (XY – Meters)
Geographic (XY: Lat, Long)
Referenced
Horizontal: NAD27 or NAD83 NAD 83 or 27 (Alaska) Vertical – NGVD 29 (m or ft) Z -NAVD88 (Meters)
Grid Spacing
30x30 or 10x10 m
30 x 30, 10 x10, 3 x 3
Geog. extent
12x14 km
N/A
Data Format
[GZ/TAR] – SDTS* Files
ArcGRID, BIL, GeoTIFF
Download at
USGS Authorized re-sellers http://gisdatadepot.com/dem http://www.mapmart.com http://www.atdi-us.com
http://seamless.usgs.gov/
* Spatial Data Transfer Standard
Copyright © 2008 Bentley Systems Incorporated
Dec-08
TRex
Page 19-4
Raster Grid Cell 1
Cell 2
A
480 m
490 m
TIN
150
145
A 137
130
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Dec-08
TRex
Page 19-5
Spatial Reference of Data and Model Must be Known
Model
DEM
DEM and Model Overlay 7.5 min Quads
Model
Copyright © 2008 Bentley Systems Incorporated
Dec-08
TRex
Page 19-6
Running TRex • Mosaic raster grids 1st (optional) • Start Stand Alone, MicroStation, AutoCAD or ArcMap • Know spatial reference of DEM & model • Confirm Units - vertical & horizontal may be different • Create new physical alternative or overwrite existing physical alternative
Copyright © 2008 Bentley Systems Incorporated
Dec-08
TRex
Page 19-7
Handling Different Elevation Data Sources
Build Data with TRex Import More Precise Data For Specific Nodes Find Missing Elevations
The End TRex – Elevation Data Import Made Easy
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Copyright © 2008 Bentley Systems Incorporated
Importing Elevations using TRex Workshop Overview In this workshop you will obtain elevation data from a digital elevation model and import it into a WaterGEMS model. The DEM is provided to you as a shapefile. The model you will be starting with has been constructed without elevation data.
Workshop Prerequisites
WaterCAD/GEMS Modeling Basics
WaterCAD/GEMS Geospatial Data Overview
Workshop Objectives After completing this workshop, you will be able to:
Import elevations using TRex
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
1
Getting Started
Getting Started In this section you will open the basic WaterGEMS starter file that does not have elevation data loaded into it. You will review the data and view your elevation shapefile as a background layer. Exercise: Opening the WaterGEMS starter file 1. Start WaterCAD V8i or WaterGEMS V8i. 2. Click Open Existing Project on the Welcome dialog or select File > Open. 3. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\TRex and open the TRex_Start.wtg file.
Exercise: Viewing the elevation shapefile as a background layer 1. Select View > Background Layers. 2. Click the New button and select New File. 3. Browse to the TRex folder and select the dempts.shp file. 4. Confirm the Unit is set to meters. 2
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
Getting Started
5. Select a Line Color of grey.
6. Click OK. You should see the model file directly overlay the shapefile itself. Note: A few nodes fall outside the DEM; you will enter those elevations manually in the next few steps.
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
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Getting Started
Exercise: Reviewing the junction data 1. Select Report > Element Tables > Junction. This will open the Junction FlexTable.
Note: The Elevation column has no data. 2. Close the Junction FlexTable.
4
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
TRex
TRex Now you are ready to generate model elevation data. You will now Populate WaterGEMS elevations from the shapefile data source. Exercise: Importing elevations using TRex 1. Select the TRex
button or select Tools > TRex.
This will open the TRex Wizard. 2. For Data Source Type, select Shapefile.
3. Select the ellipsis (…) for File. 4. Browse to C:\Program Files\Bentley\WaterDistribution\Starter\TRex select dempts.shp and click Open. 5. Set the following: Select Elevation Field:
DEMmete
X-Y Units:
meters
Z Units:
meters
6. Leave the rest of the fields with their default values.
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
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TRex
Your window should look like the one below:
Note: The Spatial Reference field is set to Unknown. This is correct because the DEM and model already are on the same spatial reference, which you saw when you overlaid the model and DEM (shapefile in this case). 7. Click Next. At this point, you will see the calculation window and TRex will begin extracting elevations.
6
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
TRex
You will receive the following message:
8. Click OK. 9. On this next screen you can preview the elevation data and now see that there are now elevations assigned to particular nodes. 10. Select the Use Existing Alternative radio button and select Base-Physical from the dropdown menu.
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
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TRex
11. Click Finish to export these elevations to the chosen alternative. Exercise: Reviewing the junction elevations and entering the missing ones 1. Select View > FlexTables. 2. Double click the Junction Table to open it.
Note: The elevation data has been transferred to the model. 3. Right click on the Elevation (m) column and select Filter > Custom. 4. Select Elevation in the left pane and double click it to add it to the query below. 5. Click the equals
8
sign and then type 0 for the value.
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
TRex
6. Click OK. 7. Right click the Elevation (m) column again and select Global Edit. 8. Set an elevation of 2555 meters at each of these nodes and click OK.
9. Right click the Elevation (m) column again and select Filter (Active) > Reset to display all junctions again. 10. Click Yes to reset the filter. 11. Minimize the Junction FlexTable. Exercise: Computing the model and reviewing the results 1. Back on the main drawing window, click Compute to run the Base scenario. Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
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TRex
2. Close the Calculation Summary. 3. Restore the Junction FlexTable and review the pressures.
4. Complete the Results Table and answer the questions at the end of the workshop.
10
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
Workshop Review
Workshop Review Now that you have completed this workshop, let’s measure what you have learned.
Results Table Node
Elevation (m)
Pressure (kPa)
Node-1 Node-1374 Node-1836
Questions
1. For a model this size, how long do you think it would take to read off all the 2000+ elevations manually?
2. Look at the number of digits past the decimal place that elevation data are reported. Is that precision justified?
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
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Workshop Review
Answers Node
Elevation (m)
Pressure (kPa)
Node-1
2555.0
440
Node-1374
2566.2
325
Node-1836
2549.3
489
1. For a model this size, how long do you think it would take to read off all the 2000+ elevations manually? At 2 minutes per node, about a week.
2. Look at the number of digits past the decimal place that elevation data are reported. Is that precision justified? No, most of those digits are meaningless.
12
Importing Elevations using TRex Copyright © December-2008 Bentley Systems Incorporated
WaterObjects.NET
Page 20-1
WaterObjects.NET Expanding your modeling limitations
WaterObjects.NET • Means of extending capability of model • Can do – Pre-processing – Post-processing – Add engines
• Cannot edit engines (cant edit Darcy or Hazen, but you can make your own) • Great for research projects
Copyright © 2008 Bentley Systems Incorporated
Dec-08
WaterObjects.NET
Page 20-2
Using WaterObjects.NET • Use any .NET compatible language • C++, C#, VB.NET, Excel Add-ins… • Sample guide and programmers guide available
WaterObjects.NET Samples Available • View database and metadata (Domain reporter) • Browse FlexTables (FlexTable Data Navigator) • Convert specific nodes to hydrants (Hydrant Converter) • Extract to Excel and create histogram (IDSE) • NPSH available calculator • Find min/max (Results Range Finder) • Determine K vs. % open (TCV Adjuster) • Customized runs (Water Quality Workstation)
Copyright © 2008 Bentley Systems Incorporated
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WaterObjects.NET
Page 20-3
WaterObjects.NET - How do I get started? • Reference material - Sample guide & programmers guide available • Contact us - we have guides and plenty of documentation for you to refer to • Join BDN (Bentley Developer Network) • Download software developer toolkit (SDK)
Histogram of Age (Calculated) (hours) for Junction elements in scenario EPS Age at time step 96:00:00 4500
Frequency
4000 3500 3000 2500 2000 1500 1000 500 0 0 - 10
10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 80 - 90 90 - 100
Ranges
Copyright © 2008 Bentley Systems Incorporated
Dec-08
WaterObjects.NET
Page 20-4
The End
Copyright © 2008 Bentley Systems Incorporated
Dec-08
References
1
Resources for Water Distribution System Modeling Books User Groups
Advanced Water Distribution Modeling and Management Contents – – – – – – – – – – – – –
Introduction to Water Distribution Modeling Modeling Theory Assembling a Model Water Consumption Testing Water Distribution Systems Using SCADA Data for Hydraulic Modeling Calibrating Hydraulic Network Models Using Models for Water Distribution System Design Water Supply Security Integrating GIS and Hydraulic Modeling Transients in Hydraulic Systems Modeling Customer Systems Operations
http://www.bentley.com/en-US/Training/Books/
Copyright © 2008 Bentley Systems Incorporated
Dec-08
References
2
Computer Applications in Hydraulic Engineering Contents
– Focuses on problem solving skills and computer modeling that will help the user become a better engineer. – NEW FOR THE 7th EDITION: • Now includes WaterGEMS and SewerGEMS • New chapter and tutorial on Dynamic Modeling • Updates on Pressure Piping and Water Quality Analysis
http://www.bentley.com/en-US/Training/Books/
Modeling Analysis and Design CONTENTS – Overview of Modeling, Analysis & Design – Fundamentals of Water Flow in Distribution Networks – Data for Network Modeling – Measurements for Network Modeling – Model Calibration – Network Models – Distribution System Planning & Design – Network Modeling Applications – Network Modeling Software – Linking with Information Systems – Management
Copyright © 2008 Bentley Systems Incorporated
Dec-08
References
3
Water Distribution Systems Handbook CONTENTS – – – – – – – – – – – – – – – – –
Hydraulics of Pressurized Flow System Design Hydraulics of Water Distribution Sys. Pump System Hydraulic Design Hydraulic Transient Design Optimal Design of Water Systems Water Quality Aspects of Construction Water Quality Hydraulic Design of Tanks Quality of Water in Storage Computer Modeling Water Quality Modeling Case Studies Calibration of Network Models Operation of Water Distrib. Systems Optimization Models for Operation Maintenance & Rehabilitation Reliability Analysis
CONTENTS – Introduction – Review of Closed Conduit Hydraulics – Solving Pipe Network Flow Problems – Using Water Distribution System Models – Sizing Water Mains – Providing and Restoring Carrying Capacity – Pipe Breaks and Water Loss – Testing Water Distribution Systems
Copyright © 2008 Bentley Systems Incorporated
Dec-08
References
4
2nd Edition 2005 CONTENTS •
Intro to Distribution System Modeling
•
Preparing the Model
•
Hydraulic Tests & Measurements
•
Steady-State Simulation
•
Extended Period Simulation
•
Water Quality Modeling
•
Advances & Trends in Network Modeling
Contents – Introduction – Modeling Water Quality in Water Distribution Systems – Tracer Studies for Distribution System Evaluation – Calibration of Distribution System Models – Monitoring Distribution System Water Quality – Geospatial Technology for Water Distribution Systems – Real World ApplicationsPlanning, Analysis & Modeling Case Studies Available for FREE at: http://www.epa.gov/ord/NRMRL/pubs/600r06028/600r06028.pdf
Copyright © 2008 Bentley Systems Incorporated
Dec-08
References
5
CONTENTS – Distribution System Water Quality – Modeling Distribution Systems – Hydraulic Analysis – Water Quality Models – Initial Modeling Studies – Modeling TTHM and Chlorine Decay – Applying Water Quality Models – Modeling Waterborne Diseases – Modeling Tanks and Storage – Getting Started in Modeling
Contact Information & Useful Links • Technical Support – 203-755-1666
• Training & Consulting – www.bentley.com
• Online Documents – http://docs.bentley.com
Copyright © 2008 Bentley Systems Incorporated
• Bentley Water & Wastewater Community @ BeCommunities – Haestad forum for questions/answers – Blogs and articles – Connect with other members – http://communities.bentl ey.com/default.aspx
Dec-08
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