1-Irrigation Development in the Philippines

INTRODUCTION IRRIGATION AND DRAINAGE ENGINEERING I

 A. IRRIGATION vs. DRAINAGE DRAINAGE 

IRRIGATION 

application of water into the soil

A. IRRIGATION vs. DRAINAGE 

DRAINAGE 

removal of excess water within or on the soil



can be natural or artificial

B. OBJECTIVE OF IRRIGATION AND DRAINAGE 

To create an environment favorable to plant growth by maintaining 

Water balance



Salt balance

B. OBJECTIVE OF IRRIGATION AND DRAINAGE 

ADVANTAGES increase cropping efficiency  increase crop productivity and yield  increase cropping intensity 

C. DEVELOPMENT OF IRRIGATION IN THE PHILIPPINES 1.

Pre-Spanish and Spanish Period 

small gravity irrigation system



communal

C. DEVELOPMENT OF IRRIGATION IN THE PHILIPPINES 2. American Regime (1900-1936) 

First Irrigation Law – BPW



Irrigation facilities 



Construction and repair

12 small & medium scale for rice irrigation 

91,000 ha

C. DEVELOPMENT OF IRRIGATION IN THE PHILIPPINES 3. Commonwealth and Japanese Regimes (1937-1946) 

Little irrigation development

4. Early Independence Period (19471965) Rehabilitation projects  NIA creation  51 small & med scale project 



122,000 ha

C. DEVELOPMENT OF IRRIGATION IN THE PHILIPPINES 5. Expansion Period (1966-1984) 

Pantabangan Dam (1969)



NIA policy making



Medium & Large Scale Projects

D. ROLE OF IRRIGATION AND DRAINAGE ENGINEERS 

FINITE FRESH WATER SOURCE

Source: WEPA, 2012

Irrigation represents the largest portion of the total water consumption in agriculture.

•

Irrigated rice accounts for about half the total harvested rice area and 70% of the total rice production.

irrigation 72%

fishery 27% others 1%

Philippine Irrigation Systems Since 1960s, irrigation systems, dams and concrete canals have been constructed to provide regular water service especially during the dry season.

Irrigation is an important strategy of the government towards agricultural productivity and food selfsufficiency. Almost 50% of the total annual expenditure of the government is allocated to improve the Philippine agricultural water resources (UN Water, 2013).

 About 9.7 million ha or 32 % of the total land area of the country is devoted for agriculture, of which 3.02 million ha is potentially irrigable but only 1.68 million ha is actually irrigated (BAS, 2015)

National Irrigation System (NIS) the largest irrigation scheme, servicing about 44 % of the total irrigated land •

Five principal river basins in the country provide water for the NIS Cagayan River basin  Agno River basin Mindanao River basin  Agusan River basin Pampanga River basin • • • • •

The service area of the NIS increased rapidly from 200,000 ha in the mid-1960 to 420,000 ha in 1990’s. But its ability to deliver sufficient irrigation water over the whole service area during the wet season has declined over time from almost 100% in 1960s to 70% in the recent years. The actual irrigated area of the NIS during the dry seasons increased from 30% in 1960s, 60% in 1980s and 70% in the recent years, attributed to the completion of the largest NIS - the UPRIIS and the MARIIS.

Poor Performance of Irrigation Systems • • •

•

•

•

deficient water supply low water-use efficiency of the irrigation subsector siltation and losses in the irrigation canals due to the degradation of watershed and severe erosion during typhoons  poor maintenance and management of the irrigation facilities underestimation of the field water requirements and water losses through diversion the overestimation of the service areas

D. ROLE OF IRRIGATION AND DRAINAGE ENGINEERS 

Development of New Irrigation Systems



Rehabilitation of National and Communal Irrigation Systems



Improving the Performance of Irrigated Agriculture



Farming Systems Diversification and Intensification



Research and Extension

Sustaining or expanding the irrigation base is the key to food security and poverty alleviation in many developing countries