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Climate change and the Indus Delta

December 15, 2008

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IN a recent session, the Sindh Assembly has adopted a consensus resolution asking the federal government to take urgent steps for checking sea intrusion into coastal districts of Thatta and Badin.

But no serious attention has been paid to the problem as the decision makers consider the water flow down stream Kotri as waste. For them, environmental flow is an alien concept. While presenting the resolution, a member of Sindh Assembly from Badin Dr Sikandar Mandhro revealed that sea has occupied 1.3 million acres in the two districts and it continues to eat 80 acres a day.

Six sub-divisions of Thatta-- Ghora Baari, Kharo Chaan, Keti Bunder, Shah Bunder and Jat-- are the worst hit. These areas were historically prosperous, engaged in extensive agriculture and trade activities. Now these areas are counted among the poorest. The drastic change has not come overnight. A significant part of over two million people of the two districts has been paying the price of wrong policies.

The Water Accord-1991 prescribed at least 10 million acre feet (MAF) water to flow below Kotri barrage to maintain fragile eco system of Indus Delta. However, this flow was seen only during high flood years when surplus was to be drained below Kotri any way. In low flow years, the delta remained dry. The flow pattern below Kotri during post Tarbela Dam years narrates the gradual unfolding of environmental disaster in Indus Delta.(see graph)

The annual average flow below Kotri during 1999-2004 was approximately 6.8 MAF and during extremely dry years of 2000-2003 it was only two MAF. The year 2001 shows the lowest flow which was less than one MAF.

In 2000-01, the government of Sindh acknowledged that 1.2 million acres of land in Thatta and Badin has been occupied by sea. Eight years past with almost similar flow conditions, the amount of land under sea must be much more than 1.2 million acres now.

Sea water erodes land and gradually submerges large tracts of land or it may temporarily inundate land during high tide (which eventually submerges the land in years to come).

The invisible form of intrusion is sub surface creep, which makes the ground water aquifers unfit for human consumption. Several villages in coastal areas had to be evacuated because their aquifers became non-drinkable. .

The most important reason triggering sea intrusion is the shortage of fresh water flows from Indus into Arabian Sea. Fresh water flows into sea has multiple benefits ranging from resisting cyclones and tsunamis to maintaining salinity in estuaries to a level where the eco-system can support aquatic life such as fish and mangroves. Due to shortage of fresh water flows, creeks have become inhospitable for mangroves and fish. According to a study “Consequences of sea water intrusion in Sindh” conducted by Indus Institute for Research and Education, creeks of Arabian Sea have become more saline than the sea itself.

Salinity in creeks has reached 3.8-4.2 against 3.6 per cent of the Arabian Sea. Salinity of water along the shores of Karachi is now at 35,500-36,900 parts per million (PPM) and has increased to 41,000-42,000 ppm in back waters and tidal creeks. The Draft Final Main Report of “Study on Water Escapages Downstream of Kotri Barrage to Address Environmental Concerns” conducted by Kotri Barrage Study-II Consultant Group in 2005 recommends that at least 15 MAF water should reach mangroves to maintain their present state and improve their environmental conditions.

Conservation of this natural eco-system creates a natural shield against climate change related natural calamities on one hand and ensures food security for masses, mainly poor (over two million in case of Sindh coast) on the other. Indus delta eco-system owes its sustenance mainly to mangroves eco-system which is rapidly vanishing due to drastically reduced fresh water flows into sea. Till late 1970s, the mangroves cover was approximately 260,000 hectares which was reduced to 160,000 hectares in early 1990s. Studies conducted by WWF put the figures to a shocking low of about 80,000 hectares in 2001.

Upstream beneficiaries of diversion of Indus water do not even consider the interest of coastal communities affected by large projects of water sector. People displaced from dam construction site are generally considered as affectees for compensation. In fact, the communities in delta pay a much higher price in case of water diversion projects.

While projecting figures of crops and electricity generation as benefits of dams and barrages, there is hardly any study which can comprehensively determine their impact of these projects on downstream areas.

Data of post-Tarbela dam shows steady decline in flow below Kotri except in high flood years when escapage below Kotri was unavoidable. During negotiations between Pakistan and India over water dispute, both countries agreed that minimum 17 MAF water has to be discharged into Arabian Sea. This quantity was reduced to mere 10 MAF in 1991 accord. “Study on Water Escapages Downstream of Kotri Barrage to Address Environmental Concerns” conducted by Kotri Barrage Study-II Consultant Group in 2005 reduced it further to 8.7 MAF. Interestingly the initial draft of the same study recommended 20 MAF flows (including 15 MAF only for mangroves) for Indus Delta.

However this figure was later altered to 8.7 MAF due to unknown (but better understood) reasons. Government has been claiming average flow below Kotri has remained 35 MAF. Even if this figure is accepted, the strange outcome is incessant disaster in the Indus delta. According to “Consequences of sea water intrusion in Sindh” conducted by Indus Institute for Research and Education” until 1960s land was advancing into sea at the rate of four km per century but now the course has reversed and near two million acres of land has gone under sea in the matter of few decades.

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 were 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. A comprehensive study should be conducted to assess ecological and socio-economic impact resulting from the dams and barrages before deciding construction of new big dams like Bhasha.

Climate change phenomenon is another upcoming challenge bound to complicate the situation further. Since 1850, sea level has risen by 165 mm.

According to Intergovernmental Panel on Climate Change (IPCC), the global temperature has increased by 0.6 0C over the last 100 years and is forecasted to rise further by 1.4 to 5.8 0C before the present century ends. This will trigger melting of glaciers resulting in further rise in sea level. Although it may bring more water to Indus Delta but after the melting phase, climate change will make Indus merely a rain-fed river.

It will alter the whole dynamics of economy, environment and life around Indus. This is high time that our decision makers seriously work on possible impact of climate change in the country and specially in Indus Delta..

The Sindh Assembly resolution demands construction of dikes to stop sea intrusion as an immediate measure; however it would bring only partial relief by stopping surface intrusion. Sub surface intrusion and seepage through dikes would continue unless sufficient flow is not maintained below Kotri barrage.