Mangroves of Indus Delta 2008

MAPPING MANGROVE FOREST RESOURCES OF INDUS DELTAIC REGION USING SATELLITE REMOTE SENSING & GIS TECHNIQUES 1.

INTRODUCTION

Mangrove forest is a diverse group of predominantly tropical trees, shrubs and associated flora and fauna and is an integral part of the inter-tidal zones of the coastal environment. It is one of the most precious resources that occur in tropical marine ecosystems and provide a range of valuable forest products and are an important source of wood, fuel wood, charcoal and fodder. These provide shelter and serve as breeding grounds for a variety of species of fish, shrimps and marine habitat as well as for certain species of birds and mammals. Shrimps are one of Pakistan’s important export commodity earning US $ 100 million annually. Moreover, mangroves stabilize the shoreline from erosion, storm damage and wave action, help in minimizing damage to property and loss of human life. Therefore, great ecological and economic importance is attached to the mangrove forest.

In Pakistan, the mangrove forests are found all along the muddy Coast of Sindh at Karachi Harbour area and in the Indus Deltaic region. Other smaller mangrove forests are Remote Sensing & GIS Applications Division of SUPARCO, June 2009

found along the Makran Coast of Balochistan, in three small isolated pockets at Miani Hor (Sonmiani Bay), Kalmat Khor and Jiwani Lagoon (Gwatar Bay). The 270 km Coastline of Sindh, extend from Cape Monze to Indo-Pakistan border, along the Arabian Sea is studded with dense to sparse mangrove forests. The mangrove forest of Indus Delta is the 2nd largest mangrove ecosystem in the sub-tropics world. This ecosystem is under severe environmental stress and is under degradation due to anthropogenic distribution. The historical record indicates that the mangroves were distributed over a very large area in the Indus Deltaic region, but during the past five decades, a significant change has been observed in mangrove forest area. This ecosystem has suffered a great damage due to human and natural interventions, like; 

The reduced flow of sweet water and silt from the Indus River,



Intrusion of seawater,



Meandering and erosion of creeks,



The gradual increase in sea level,

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO



The inflow of pollutants,



Grazing and browsing by camels and buffaloes,



Cutting of mangroves for fuelwood collection,



The coastal process and



The cyclones.

The mangroves grow best where an adequate fresh water supply is available, with constant injections of nutrients and salt from the upland catchments areas. The reduced inflow of fresh water downstream Kotri Barrage due to construction of dams and reservoirs on Indus River and on other large rivers for agricultural needs and for the production of hydroelectric power, increasing the salinity of both the surface water and sediments load; and thus affecting the growth of mangrove plantation. Out of eight mangroves species, only one mangrove specie, Avicennia marina (Teemer) – a high salt tolerant specie is present in the deltaic region, which covers about 92% of total mangrove forests area, the other seven species have been seriously affected by changing environmental conditions. The mangrove forest is an important source of fuel wood for people, mostly fisherman living along the coastal belt. Over 60% of the local population use Avicennia marina (Teemer)

as their major source of fuel. Avicennia leaves are excellent fodder for animals and the villagers collect their leaves for feeding of cattle, sheep and goats. Human activities induced on the Coast of Karachi for urban development, which could further degrade the local mangroves. Additionally, the mangroves along the Coast of Karachi are also facing problems of pollution from sewerage water and industrial wastes coming from Lyari and Malir Rivers and from Gharo Creek to Indus Delta and from the oil and bilge waste discharged by ships visiting Karachi and Bin Qasim Ports and as a result, they are suffering from environmental degradation and are deteriorating at many places. Mangrove forest is the major ecological features in the Indus Deltaic region and playing an important role in the biodiversity and breeding ground for shrimps. Therefore, there is a need to monitor this ecosystem and assess the qualitative and quantitative changes occurring in the mangrove ecosystem using advanced technology like satellite remote sensing. The Satellite Remote Sensing (SRS) offers a rapid and non-intrusive means of making large scale measurements on a variety of mangrove parameters. SRS data have been successfully used to assess and map the mangrove forests and other coastal features in the coastal areas of Pakistan, to assess and 2

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

monitor deforested or afforested areas, to examine mangrove zonation, to plan aquaculture sites, and to monitor and map oil spills areas. Therefore, on the request of Coastal Forest Division (CFD) of Sindh Forest Department (SFD), a study was initiated with the aims to accurately map and assess the coastal resources of Sindh, especially the current status of mangrove forests, along the Coast of Karachi and in Indus Deltaic region. A similar kind of study was conducted for the CFD of Sindh in 2005, with the aim to assess and map the mangrove forests and other coastal features in the lower part of Indus Delta, from Dabbo Creek to Sir Creek, using SPOT XS data of January 2005. The current study is an extension of the previous study, covering the entire Coast of Sindh from Cape Monze to Sir Creek, and using the latest SPOT XS data of Nov. 2008.

2.

AIM OF THE PROJECT

The current study is aimed to map and assess the mangrove forests cover and other coastal features in the Indus Deltaic region and in Karachi Harbour area, using Satellite Remote Sensing and GIS techniques. The assessment includes collection of reliable and up-to-date information on the current status of mangrove forests and other coastal features along the entire Coast of Sindh, including the

Karachi Harbour area and Indus Deltaic region; and to monitor changes taking place in the mangrove forest of Indus Delta.

3.

DESCRIPTION OF STUDY AREA

The study area constitutes the entire Coast of Province of Sindh lies, between longitude 66°50`E to 68°30`E and latitude 23°40`N to 24°55`N, covering the coastal areas of Karachi, Thatta and Badin Districts and consists of Indus River delta and the adjacent belt of low lying areas and shallow depressions. The Coast of Sindh extends from Cape Monze in the west to Indo-Pakistan border in the east, covering a length of 270 km, along the Arabian Sea. This coast has been divided into the western coast and the southeastern coast. The western coast extending from Hub River fall near Cape Monze to Karachi consists of rocky shores, sandy beaches, backwater, estuaries and mangroves. The south-eastern coast consists of 17 major creeks and innumerable minor creeks of the delta and inshore waters with tidal mud flats, creek channels, sandy areas and fringing mangroves, which have the usual mixing of fresh water from the Indus River and salty water from the Arabian Sea. The Indus River deltaic system is one of the largest deltas of the world, situated on the southeastern border of 3

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

Pakistan near Rann of Kutch (India). It is a typical fan shaped delta, built by the discharge of large quantities of silt washed down by the Indus River from the Karakoram and Himalaya mountain ranges. The coastal zone of the delta from the shoreline to the extent of mud flats covers an area of about 9,930 sq. km. The mangrove forest of Indus Delta is the 2nd largest in the sub-tropics world, dominated by mangrove specie Avicennia marina (local name Teemer), which covers about 92% of total mangrove forests area. Other three mangrove species: Rhizophora mucronata (Kumri), Ceriops tagal (Kiriri) and Aegicerus corniculatum (Chaunr) are also present in some parts of the Indus Delta, but on very small area, covering about 8% of total mangroves area. The location of the study area is marked on satellite image mosaic of the Province of Sindh, shown in Figure 1. 4.

MATERIALS USED

In this study, following materials have been used: i)

SPOT XS digital data acquired in Oct. / Nov. 2008, covering the entire Coast of Sindh from Karachi to Sir Creek

5.

ii)

Historical SRS data for comparison and for monitoring dynamic changes in the area

iii)

Reference maps for Image geo-coding / georeferencing and annotation

iv)

Ground surveys information. METHODOLOGY

For coastal resource assessment, SPOT XS digital data of 2008 were processed using digital image processing and Geographic Information System (GIS) techniques. SPOT XS images (raster data) were extracted, enhanced and displayed in color composite forms. Image geo-coding was applied on the raw enhanced images to rectify the images to the real world coordinate systems. In order to compile a single image of the entire study area, all the SPOT rectified / geo-coded images were mosaiced digitally. Colour balancing was applied to create seamless joins between them. To use only the requisite area of the Indus Delta, the boundaries of the extent of mud flats (coastal areas) were digitized and the areas lying outside were masked. This enabled delineation of accurate landuse / landcover classes. SPOT XS color composite image mosaic of Coast of Sindh covering Karachi 4

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

Harbour area and the entire Indus Deltaic region covering all major and minor creeks is shown in Figure 2. The coastal features within the study area, like different densities of mangrove forests (dense, medium and sparse), the position of creeks / channels, mudflats and sandy areas, etc have been digitized by on-screen digitization technique using AutoCAD Map 2000, and using the image mosaic of Indus Delta and the GIS based vector layers of these coastal features have been developed. Small towns / villages and road network, as seen on the SPOT images were also digitized and delineated and annotated to produce another vector layer for integrating with digitized layers of mangrove forests, sandy area, mudflats and creeks / channels layers. It may be mentioned that the quantitative assessment of mangrove forest and other coastal features are not entirely based on interpretation of satellite images, it also require the analysis of the various components of whole environment prevailing in the respective study areas, such as background knowledge of the area, local environmental conditions and the probable factors influencing the ecosystem, e.g., human activities, natural hazards, conservation measures, etc. Therefore, for background knowledge of the area, historical available Landsat TM data of 1989 & 1998; and SPOT XS data of 2003 & 2005 were analysed. Ancillary data and

other ground based information have also been collected. For this purpose, the ground surveys of western part of Shah Bandar area and north-western part of Keti Bandar were conducted on 6th and 7th November 2008, respectively, with the assistance of Divisional Forest Officer (DFO) and Range Forest Officers (RFO’s) of the respective sections of Coastal Forest Division. The surveys were supported by GPS, the previous categorized landcover maps based on SPOT XS data of 2003 and 2005; of ground survey’s sites, extensive photography and field survey proforma. Information collected through ground observations and from the RFO’s and other staff members of Coastal Forest Division were also incorporated for improvement and verification of satellite based results. GIS based mangrove forests map of Indus Deltaic region, i.e. from Karachi to Sir Creek, has been compiled using map composition and GIS techniques, at 1:250,000 scale and is shown in Figure 3. Detailed maps of some parts of Indus Delta, viz-a-viz from Korangi Creek to Paitiani Creek, Paitiani Creek to Hajamro Creek including the town of Keti Bandar, mouth of Indus River covering Turshian River to Kharak Creek, Shah Bandar area and northern part of Sir Creek covering Shah Samando Creek and western part of Tidal Link, have been compiled at 1:50,000 scale and are included in the report as Annex - I, 2, 3, 4 & 5, respectively. 5

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

6.

RESULTS AND DISCUSSIONS

The enhanced satellite image of the coastal belt of Sindh, shown in Figure 2, represents the current status of mangrove forest and other coastal features in the Indus Deltaic plain. On this image, the mangroves appear in different shades of red, depending upon their densities and canopy cover. The dense mangroves, which has large canopy cover and are in good and healthy conditions, i.e., having high chlorophyll concentration appear with bright red, due to high reflectance in the near-infrared band. The medium density mangroves appear in medium red and scattered or sparse mangroves appears in yellowish red colour because of less canopy cover and reflectance of vegetation plus the reflectance of ground soil. Natural vegetation, which grow in water or in moist soil appear with brownish red colour, because of the presence of moisture in the soil has appreciably reduced the solar radiation from such area on account of typically low reflectance of water / moist soil in the near infrared band. Mudflats appear in gray and the dry sandy beaches due to high reflective materials (sandy / silty soil) appear with bright white tone. The water has low reflectance in the visible, as well as in the infrared channel, due to absorption of solar radiation and due to this reason the deep sea appears black, showing no sedimentation or turbidity in the water, whereas the near Remote Sensing & GIS Applications Division of SUPARCO, June 2009

shore water and creek / channels are in dark to light blue color, depending upon concentration of sediments / turbidity in the seawater. The mangrove ecosystems of Karachi Harbour area and of the Indus Deltaic region are undergoing changes, due to natural and human interventions, therefore, regular monitoring and mapping of mangrove ecosystem is necessary for preservation and protection of such precious resources from further degradation. For this purpose, the mangrove forest map of the entire Coast of Sindh, based on current SPOT XS data of November 2008, have been prepared using SRS& GIS based techniques, and is shown in Figure 3. This map represents the different densities of mangrove forests and other coastal features like sandy areas, mud flats, creek / channels, etc, along the Coast of Sindh. The mangroves of Sindh are discussed in details as below:

6.1

The Coast of Karachi

The Coast of Karachi covers the area from Cape Monze to Chinna Creek. The area from Cape Monze to Sand Spit is a rocky - sandy barren coast and devoid of vegetation. The mangroves in the Karachi Harbour area are found in the

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

backwaters of Manora Channel and in Chinna Creek. The enhanced SPOT XS image of November 2008 of Karachi Harbour area is shown in Figure 4. This area has well developed and close canopy mangrove forests, especially at Sand Spit and Manora Island. The only mangrove specie Avicennia marina (Teemer) has been found in this area. Based on SPOT image of 2008, a GIS based landuse / landcover thematic map, showing mangrove forest and other coastal features like marine algae, creeks / channels, sandy area, salt work areas, different types of water (deep water, shallow water, turbid water, highly turbid water), etc, has been prepared and is shown in Figure 5. From the landcover thematic map, the area under each mangrove class has been estimated, and is given in Table I. The mangrove forest at Karachi Harbour area are spread over an area of 1,160 hectares (ha), out of which the dense mangroves cover an area of 630 ha, medium densities mangroves on 385 ha and sparse mangroves on 145 ha. The marine algae spread over an area of 920 ha, sandy area covers 1,270 ha and muddy areas occupy 710 ha.

The Coastal areas of Karachi are facing various problems, especially the Karachi Harbour area, which has almost all forms of pollution that might be expected within an urban environment close to the seaport. A large amount of

polluted water-sewerage water and industrial waste of Karachi City, coming from the Lyari River into the Manora Channel, increase the marine pollution in the area. This polluted water may provide nutrients to mangroves and decrease the salinity level in the channel and seems locally to their benefit, but increase the pollution in the backwater of Manora Channel, and produced the marine algae. The increase in marine algal cover is very prominent in the current satellite image of 2008, as compared with the satellite image of 1989, which appears with the dark brown patches in satellite images. The marine algae were spreaded over mudflats and in backwaters of Manora Channel in mangroves harvesting areas. Oil pollution is also increasing on the Coast of Karachi, particularly in the backwaters of Manora Channel and in Chinna Creek, due to increase in the ship traffic. The surface deposits of crude oil and bilge wastes are interspersed in seawater but these materials seem to have little or almost no effect on structure and functioning of the mangrove forest. The human activities going-on, at the Coast of Karachi for urban development, like the development of land for construction in Gizri Creek and in Chinna Creek near Boating Basin, is further reducing the growth of local mangroves.

7 A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

TABLE – I: Sr. No.

Class

Colour

Area in Hectares

6.2 Area in Sq. Kms

%

1

Dense Mangroves

Magenta

630.00

6.35

3.94

2

Medium Mangroves

Green

385.00

3.85

2.41

3

Sparse Mangroves

Orange

145.00

1.45

0.91

4

Marine Algae

Yellowish Green

920.00

9.20

5.75

5

Sandy Area

Yellow

1,270.00

12.70

7.94

6

Muddy Area

Gray

710.00

7.10

4.44

7

Deep Water

Dark Blue

3,765.00

37.65

23.55

8

Shallow Water

Navy Blue

7,670.00

76.70

47.97

9.

Turbid Water

Light Blue

495.00

4.95

3.09

15,990.00

159.90

100.0

Total

The Indus Deltaic Region

The Indus Delta spread from Korangi Creek to Sir Creek consists of 17 major creeks, namely; the Korangi Creek, Phitti Creek, Waddi-Khuddi Creek, Khai Creek, Paitiani Creek, Dabbo Creek, Chhan Creek, Hajamro Creek, Turshian River, Khobar Creek (Jangh River), Qalandri River, Gahbar Creek, Khar Creek, Kharak Creek, Pakhar Creek, Kajhar Creek and Sir Creek; and numerous minor creeks, mudflats, sandy areas and tidal creeks that are lined with dense to sparse mangrove forests on sand-silt substrate. The enhanced SPOT XS mosaic image and GIS based mangrove forest map of Indus Deltaic region based on SPOT XS data of 2008 are shown in Figures 6 and 7, respectively. This map represents the current status of mangrove forests in the Indus Deltaic region. On this mangrove forest map, the dense mangroves are represented by magenta, medium density mangroves by green and sparse mangroves by orange colour, mudflats are shown in gray and dry sandy beaches are delineated with yellow colour. Small towns / villages, the road network, as identified on SPOT XS images are marked and delineated on the mangrove forest map of Indus Delta. The area under each mangrove class has been estimated from the landcover map and is given in Table – II. The total mangrove forest area in 8

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

Indus Deltaic region are estimated to be 106,480 hectares (ha), out of which the dense mangroves are spread over an area of 25,320 ha, medium density mangroves on 34,700 ha and sparse mangroves are spread on 46,460 ha, sandy area covers 9,100 ha, and mud flats occupy 183,250 ha.

The historical satellite data provide great means in analyzing the successive changes occurring in the landuse / landcover features and in the natural resources, e.g., mangrove forest cover. Therefore, historical Landsat TM data of 1989 & 1998 and SPOT XS data of 2003, available in digital form in SUPARCO archives were used for comparison and analysis. These data sets have also been used to study and understand the coastal processes and their impacts on tidal / inter-tidal zones and in low lying areas of Thatta and Badin Districts. From the analysis of historical SRS data, it is observed that the mangrove forest was spreaded on very small area in 1989, which increased gradually and became doubled in 2008. The increase in mangrove forests area is the result of plantation of fast growing and high salt deserted mangrove species, Rhizophora mucronata (Kumri), and also of Avicennia marina (Teemer) in the inter-tidal zones of the Indus Delta. However, the mangrove forest are deteriorated by various human induced factors like; indiscriminate use of

TABLE – II: Area Summary Report of Mangrove Forest of Indus Delta based on SPOT XS Data of 2008 Sr. No.

Class

Colour

Area in Hectares

Area in Sq. Kms

1

Dense Mangroves

Magenta

25,320

253.20

4.22

2

Medium Mangroves

Green

34,700

347.00

5.78

3

Sparse Mangroves

Orange

46,460

464.60

7.74

4

Sandy Area

Yellow

9,100

91.00

1.52

5

Mud Flats

Gray

183,250

1,832.50

30.54

6

Creeks / Channels/

Navy Blue

301,170

3011.70

50.20

600,000

6,000.00

100.0

Sea Water

Total

%

9 A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

these forests for firewood, timber, fodder and fishing related products, water pollution and the reduction in flow of fresh water and increase in salinity in the Indus Deltaic region.

The mangrove forest in the Indus Delta have been observed in two compact blocks, the northern block and the southern block and middle part covers mouth of Indus River, which is barren and devoid of vegetation, as discussed below:

6.2.1 The Northern Block of Mangrove Forest The northern block of the Indus Delta covers the area between Korangi Creek to Chhan Creek. This area has well developed dense mangrove forest stands on sand / silt substrate, numerous tidal creeks, mudflats and sandy beaches. The sandy areas are completely barren and behind the sand, extensive mudflats are covered with varying densities of mangrove forests (dense, medium and sparse), with close canopy and vigorous appearance, as shown in Figure 8(a) and its categorized landcover map is shown in Figure 8(b). The northern part of this segment is under the control of Port Qasim Authority and is a protective zone; because of this, the area has well developed mangrove forest stands of dense canopy cover. The major part of this

segment is covered with mangrove specie Avicennia marina, but other mangrove species Rhizophora mucronata, Ceriops tagal and Aegicerus corniculatum have also been observed in this region. Tall trees of Avicennia marina, 10 – 12 ft, with large canopy cover have been observed in this part of the delta. Mangroves specie Aegicerus corniculatum is also observed in this area at Waddi-Khuddi and Dabbo Creek, and are found in good and healthy conditions. Ceriops tagal is naturally present in the area. Its leaves are very similar to Avicennia marina, but have small canopy cover and are of very small heights, upto 2 – 4 ft. Normally, A. marina specie attains 10m heights in 30 – 35 years in regularly inundated areas but become stunted in hostile conditions. The ground views of mangroves species Avicennia marina, Rhizophora mucronata, Ceriops tagal and Aegicerus corniculatum are shown in Figures 9 (a, b, c & d), respectively.

On comparison of satellite images of 1989, 1998 and 2003 with 2008 image of the northern block of mangroves, no major change has been observed in this block, except in the Korangi-Phitti Creek area, along the eastern Coast of Karachi. The mangroves in this part of the delta are harvested for cattle and camel fodder during the dry season, as the mangroves represent the only green foliage present in the region during the dry winter season. Mangrove trees are 10

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

also cut for fuel purpose and thus this part of the delta is under influence of heavy grazing pressure during the dry winter season by the local inhabitants.

is due to increase in marine pollution in the area. This polluted water thus affecting the growth of young mangrove plantations and these are therefore dying.

The second major urban industrial center of Karachi is located along the eastern Coast of Karachi near Indus Delta and another small urban industrial center in the area is Gharo in Thatta District. The Malir River contributes a large amount of polluted sewerage water and industrial wastes of eastern part of Karachi City into the Gizri, Korangi and Ahsan Creeks. A large number of textile and other industries, located at Gharo in Thatta District also increase the marine pollution in the area. This is adversely affecting the ecology of the estuary and creek areas, and marine algae is also growing in the mangrove habitat in the water of Korangi - Phitti Creeks, indicates the presence of increased marine pollution in the creek waters. The dark brown patches of marine algal cover were very prominent in the current SPOT image of 2008, on the mud flats and in the waters of Gizri, Korangi, Ahsan and Gharo Creek areas in the mangroves habitats. This has also been identified during the ground survey of area near Rehri Goth and Lat Basti. On comparison of satellite images of 1989, 1998, 2003 and 2008, it was observed that the marine algal cover in this part of delta has been increased between 1998 and 2008, which

6.2.2 The Middle Part of Indus Delta The middle part of study area covers the mouth of Indus River, covering the area from Hajamro Creek to Khar Creek, and the town of Keti Bandar, which is a well-known small fisherman’s village, situated within the delta to the north west of the major Indus spill River. This part of Indus Delta is almost barren and lies under the control of Sindh Board of Revenue. SPOT XS image of this part and its categorized map is shown in Figures 10 (a & b), respectively. In the past 50 years, the construction of dams and barrages and increased utilization of fresh water from the Indus River for irrigation and for generation of hydroelectric power, the Indus River now mostly discharges fresh water to the sea only during monsoon flooding. During the other remaining months of the year, the Indus River has very less or no water. The reduced supply of fresh water downstream accelerated the pace of seawater intrusion into the riverine tract, which goes up about 65 km, upto Thatta – Sujawal Bridge. The seawater intruded initially the tidal zone and slowly and gradually flowed upstream in the main course of 11

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

Indus River, which brinks ecological disaster in the Coastal areas of Sindh, especially in the Thatta and Badin Districts, where thousands of hectares of cultivated lands have been converted into waterlogged and under high salinity. The effect of intrusion and the increase in soil salinity appears very prominent in the current SPOT image of 2008 with white tone. The reduced inflow of fresh water ostensibly increasing salinity of both the surface water and sediments load and decreasing the nutrient supply from the terrestrial fresh water in the Indus estuary, there by killing mangrove communities, as well as the riverine forests near the mouth of the Indus River. With regard to sea intrusion towards the land area, the tidal boundaries have been drawn from historical SRS data of 1976, 1989, 1998 and 2003, and integrated with SPOT image of 2008. From integration, it is observed that the impact of coastal process has been more at the middle and on the south-eastern parts of the delta, especially from Keti Bandar to Dhands areas in Badin District and very little variation has been seen on the northwestern part of the delta.

Creek and Hajamro Creek, situated in the north-west of town of Keti Bandar. This area is now under sparse mangrove vegetations of 2 – 5 ft height. The ground views of mangrove nursery, new planted mangrove trees, medium density mangroves and dense mangrove forests observed near Keti Bandar are shown in Figures 11 (a, b, c & d), respectively. The CFD also planted high salt deserted mangrove specie in 1986 – 1988, and further in 1999 – 2002 in the tidal zones, near the Sanhri and Gahbar Creeks. This area is closed to open sea and the mangroves in this area are at an unapproachable distance; and are therefore, protected from harvesting. It was also observed that the land accretion has also taken place, after plantation of mangroves on the mudflats between Sanhri and Gahbar Creeks. The increase in mangrove forest area and land accretion taken place in this part of delta are shown in the zoomed satellite images in Figures 12 (a & b), respectively. This shows that plantation of mangroves on barren mud flats, especially near the coastline, will help in binding the soil and protect the land from extensive erosion by sea tide actions.

To create biodiversity, the Sindh Forest Department with the financial assistance of World Bank, has planted four indigenous mangrove species in 2002 (mentioned above), at suitable sites in the inter-tidal zones, in area between Chhan

6.2.3 The Southern Block of Mangrove Forest The southern block of Indus Deltaic region covers the area from Shah Bandar to Pateji Dhand and from Khar Creek to 12

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

Sir Creek and is close to Rann of Kutch of India. This zone is under the protection of Coastal Forest Division. Another small well-known fisherman village, Shah Bandar is situated to the north-east of the major Indus spill River within the delta. The SPOT XS image of the southern block of Indus Deltaic region and its categorized landcover map are shown in Figures 13 (a & b), respectively. The upper part of this block is barren and the lower part has stunted growth of mangrove vegetation. Under the rehabilitation plan, IUCN and CFD planted a fast growing and high salt deserted mangrove species, Rhizophora mucronata (Kumri) in 1986 – 1988, in the inter-tidal zone near the town of Shah Bandar. In the satellite image of 1989, this area was under water, and very sparse mangrove vegetation have been observed in the lower side, which became under dense vegetation (medium to dense mangrove plantations), as appears in the Landsat image of 1998. In SPOT 2008 image, this area has same medium to dense mangrove plantations of Rhizophora mucronata of 10 – 14 ft heights. From the comparative satellite images of 1989, 1998 and 2008, shown in Figures 14 (a, b & c), respectively, it was observed that the small patched of mangroves in the lower side of Shah Bandar forest have been deteriorated, which may be due to high salinity in the area and non-availability of fresh water. The high salinity on the mud flats and degraded mangroves as

observed in the ground survey of the area are shown in Figs. 14 (d & e), respectively. Mangrove nursery of R. mucronata established in the inter-tidal zone near the old town of Shah Bandar by CFD and sparse mangrove trees of R. mucronata; and dense and medium density mangrove forest of A. marina observed in the western part of Shah Bandar area are shown in Figures 15 (a, b, c & d), respectively.

In the recent past (in 1995), a Tidal Link drain, which is the main outfall component of Left Bank Outfall Drain (LBOD) has been constructed, with the primary aim to reclaim the agricultural lands of Sanghar, Nawabshah and Mirpurkhas Districts by reducing the watertable, thereby reducing the salinity, and drain the agricultural effluents containing excessive salts and saline water from LBOD to Arabian Sea through Tidal Link drain and Shah Samando Creek. In May 1999, a powerful Cyclone TC – 02A devastated 160 km Coastline of Sindh from Indian border to Keti Bandar, including a large part of Thatta and Badin Districts and the mangroves in the south-eastern part of delta, especially the Rhizophora were badly effected. The catastrophic effects of this cyclone resulted in severe damage of the Tidal Link drain from several locations, and have greatly damaged the ecology of the area, resulting in degradation of thousands of hectares of agricultural land in Badin District, by increasing 13

A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

the waterlogging and salinity in the area. The enhanced satellite images of 1989, 1998 and 2008 of south-eastern part of delta near Rann of Kutch, has stunted growth of mangrove vegetation, as shown in Figures 16 (a, b & c), respectively. In 1989, this area has several small and large patches of dense to sparse mangrove vegetation, the size and canopy cover was decreased in 1998, and which was further decreased in 2008 image, as appears in the comparative satellite images of 1989, 1998 and 2008. The

deterioration of mangroves in this part of delta may be due to shortage of fresh water and high salinity in the area. Sea water salinity and turbidity is also very high in this part of the further decreased in 2008 image, as appears in the comparative satellite images of 1989, 1998 and 2008. The deterioration of mangroves in this part of delta may be due to shortage of fresh water and high salinity in the area. Sea water salinity and turbidity is also very high in this part of the delta, especially at Kharak, Pakhar, Kajhar and Sir Creeks.

14 A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

7.0

CONCLUSION AND RECOMMENDATIONS

From this study, it is concluded that:  The SPOT XS data of 2008 used in this study are found suitable for current assessment and development of most recent database of coastal natural resources, like mangrove forests and generation of GIS based mangrove forest maps of inaccessible Coastal areas of Sindh.  In the current investigation, 20m SPOT XS data has found useful in discriminating at least three categories of mangrove forests (dense, medium and sparse), through their tone and vigor and other coastal features like mud flats, sandy and saline areas, etc. However, due to mixed plantations, it had been difficult to distinguish between different mangrove species grown in the same parts of Indus Deltaic region. It is to be noted that the satellite sensors can discriminate mangrove zonation on the basis of canopy cover but discriminating different species under prevailing environmental conditions cannot be made.

 From the analysis of SPOT XS data of 2008, it is estimated that the mangrove forests are spread over an area of 107,640 hectares along the Coast of Sindh. Out of which, the mangroves in Karachi Harbour area is spread over an area of 1,160 hectares and about 106,480 hectares in the Indus Deltaic region.  After a thorough study of all mangroves sites in the study area, it is concluded that the decrease in mangrove forest area has been observed in some specific places, which could be due to indiscriminate use of mangroves trees for grazing and fuel purposes (due to increase in the prices of oil, wood, charcoal, etc.) by the local inhabitants, shortage of fresh water supply, as well as affect of cyclones / hurricanes. However, it was also noted that the deterioration has been taken pace at a very small scale and afforestation have taken placed at large scale. The conservation measures taken by Coastal Forest Division in collaboration with other departments have improved the growth of mangroves in the delta.

15 A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009

Mapping Mangrove Forest Resources of Indus Deltaic Region using Satellite Remote Sensing & GIS Techniques – A Collaborative Project of Coastal Forest Division of Sindh & SUPARCO

 The plantation of high salt tolerant and fast growing mangrove specie, Rhizophora and Avicennia, carried out in the inter-tidal zones of Indus Delta, has provided positive results. This could not only increase the forest area, but also help in binding the soil and protect the coastline and delta from extensive erosion through high tides.  The GIS based mangrove forest map of Indus Delta at 1:250,000 and detailed maps at 1:50,000 scale of different parts of delta are of great significance in the planning and management of coastal areas of Sindh. These maps can provide important and useful information regarding rehabilitation and/or conservation of mangrove forests, especially the details maps at 1:50,000 scale, could help Coastal Forest Division in identifying appropriate sites for plantation of mangroves in barren areas of the delta, because a large part of mud flats near the mouth of Indus River and in the upper eastern part of delta are barren.  From the analysis of temporal SRS data of 1989, 1998, 2003, 2005 and current 2008 data, it was observed that the surface salt accumulation and

dryness in the deltaic region have been increased due to non-availability of fresh or sweet water from Indus River and intrusion of seawater in the Indus Delta creek system through the riverine tract and channels. The increase in waterlogging and salinity in inland areas of Thatta & Badin Districts, indicate that the seawater is intruding in ground water aquifers and destroying the agricultural land. Therefore, there is a dire need to increase the inflow of fresh water in Indus downstream, which would certainly help in decreasing the salinity level in the deltaic region and turbidity in the seawater and provide nutrients for the growth of mangrove plantations from the terrestrial (fresh) water runoff, because hyper-salinity and turbidity are harmful to fish production and marine life.  From the analysis of temporal SRS data, it was also observed that the dryness in the eastern part of the delta near Tidal Link drain has been increased due to intrusion of seawater through the Shah Samando Creek and from breaches occurred in Tidal Link, which deteriorated the dhands and the surrounding environment.

16 A Collaborative Project of Coastal Forest Division of Sindh Forest Department and SUPARCO, June 2009