Declining fresh water flow poses a grave threat to Indus delta and coastal communities
WWF has placed Indus Delta among the ecologically significant 200 eco-regions in the world. River Indus, which forms the Indus delta, originates from Himalayas and debouches in Arabian Sea after traversing a distance of about 2,900 kms. The Indus River at the point of confluence with the sea forms a valuable mangrove eco-system that bestows sustenance to a highly productive marine eco-system on the 330 km long coast of Sindh. Coastal communities earn their livelihood through traditional fishing, agriculture and forest resources in the delta. The marine eco-system husbanded by the delta, contributes over two per cent of the national exports and is the primary source of livelihood for local communities.
Politicians and bureaucrats of Punjab often belabour that 20 to 35 million acre feet (MAF) of water are being wasted to sea every year. The data, however, shows a different reality. Except for high flood years, flows below Kotri barrage have remained far less than even 10 MAF agreed in the water accord of 1991. Looking at the 13 year period from 2000-01 to 2012-13, it can be seen that flows at Kotri barrage surpassed 10 MAF in only 6 years i.e. less than half of the years. The average surplus in the last 15 years remained only 3.32 MAF. Whereas the average surplus flow between 1999 and 2009 remained merely 0.3 MAF. It was the enormous flow generated by the unprecedented floods in 2010 that augmented the averages of past 15 years. Even these meager flows are available for only two months coinciding with the peak monsoon time. This provides only a fleeting relief to delta and cannot rejuvenate its ecology. Hence, the average surplus flow has remained highly erratic and unreliable to propose any large dam.
Sitting in the cozy rooms of Islamabad, no one can imagine the miseries of people living on both sides of the Indus which spreads over 100 kms between Kotri barrage and sea during lean flow years. Even if one surmises that 20 to 35 MAF water is flowing to the sea, one wonders why the ecology of the delta is continuing to suffer. This simple logic corroborates the claim that the Indus delta needs much more than current flows for its ecological sustenance. Probably this is the single largest cause of the environmental havoc in the delta and all other impacts are only by-product of this major cause.
Till the 19th century, the delta would receive annually approximately 150 MAF water from the river system. This quantity was gradually curtailed due to upstream developments in the shape of a series of dams and barrages. After the conquest of Punjab in the second half of the 19th century, the British government initiated massive irrigation development projects to divert Indus basin’s water to the fields of Punjab through a series of barrages and an extensive canal network including Sutlej valley development project in the early 20th century.
After the country came into being, a number of huge water sector development projects including two big dams Tarbela and Mangla along with Jinnah, Kotri, Marala, Taunsa and Guddu barrages have been implemented without taking into consideration their downstream ecological impacts. Under the Indus Basin Treaty three eastern rivers were completely surrendered to India. The treaty was ensued by an extensive replacement network of link canals in Punjab but no replacement was considered for Indus delta that lost 10-15 MAF water that used to flow from the eastern rivers.
According to a document of the IUCN, “Mangroves: Status and Management”, this relentless upstream diversion shrunk the active Indus delta from 26,000 sq.kms to approximately 1190 sq.kms. Indus delta originally occupied an area of about 600,000 hectares, consisting of creeks, mudflats and forests between Karachi in the north and the Rann of Kutch in the south. There are 16 major creeks making up the original delta but due to reduced flows below Kotri, only the area between Hajamro and Kharak creeks now receives water from the Indus, with one main outlet to the sea, Khobar Creek. The active delta is now only 10 per cent of its original area. According to some recent estimates, more than two million acres of land in coastal districts of Sindh have been devoured by sea.
Till the slate 70s, the mangrove cover was spread over 260,000 hectares, which reduced to 160,000 hectares in the early 1990s. The recently conducted studies by WWF put the figures to a shocking 80,000 acres only. Mangrove eco-system supports the marine life chain while acting as a nursery for fish and shrimp. About 150 fish species are known to depend on mangroves, some of them with significant commercial value.
A major cause of the dreadful conditions is inadequate freshwater flow to the delta since the mangrove forests require sustained fresh water flows to maintain water salinity levels. Increasing salinity levels has resulted in asphyxiation of four mangroves species in the Indus delta. Out of the remaining four species, the predominant one is the species that has a high level of salt tolerance ,“avicennia marina”. This accounts for more than 97 per cent of the surviving mangroves forest.
Reduced fresh water flows resulted in less silt deposition to abate the sea vector – this has invited more erosion through tidal action. The resulting loss of land is coupled with a hazardous accumulation of salts, which has also rendered local aquifers unfit for agricultural and human consumption.
According to a report of The World Bank “The Indus Basin of Pakistan”, over the last 20 years, at least 2 million acres of arable land have been lost in Sindh as a result of salt water intrusion. Just a few decades back, the area was known for its agricultural product and it was a primary source of livelihood. Fishing has replaced the economic focus of the area and the whole scenario has been subjected to a big socio-economic turbulence. This transition has resulted in loss of livelihood for several thousand people, pushing them below the poverty line.
According to a report “Study on Water Escapages Downstream of Kotri Barrage to Address Environmental Concerns” issued by Kotri Barrage Study-II Consultant Group in 2005, at least 8.7 MAF water is required for Indus delta. However, the study suggested that the water should be evenly distributed over the year by ensuring at least 5000 cusecs on daily basis. Unfortunately, the recommended quantity of minimum daily flow is flagrantly violated by the water bureaucracy of Pakistan.
There is an urgent need to conduct a detailed study to assess environmental and socio-economic impacts on the Indus delta and its communities after construction of dams and barrages during recent decades. Sindh coast should be declared an eco-disaster hit area and a comprehensive eco-rehabilitation programme should be launched in the area. A similar programme should also be launched to monitor sub-surface and on-surface sea intrusion. This would also require monitoring of ground water quality at least up to 100 km upstream of sea in Thatta and Badin districts to establish the pace of sea accretion.
For regular monitoring of impact on Indus Delta, a comprehensive baseline should be conducted on natural resources and socio-economic conditions in the delta. GIS and satellite imageries should be used to make the data free from human errors and prejudices. Concomitant to that, a long term rehabilitation programme for Indus delta eco region should be launched. The programme should focus on resuscitating natural resources of Indus delta and rehabilitating coastal communities who have paid enormous price for economic prosperity in the upstream areas. Unfortunately, coastal communities are not even recognised as affectees of mega projects in the water sector.
A rich and prosperous agriculture economy in upstream areas has deprived coastal communities of their livelihood resources. Vagaries of climate make the Indus delta even more vulnerable to sea intrusion, cyclones, tsunamis and other potential disasters.