Wish upon a lake

Will Kalpasar quench Saurashtra's thirst?

By Subhrangsu Goswami
Published: Sunday 07 June 2015

Wish upon a lake

-- The Controversies over the multi-crore Sardar Sarovar Project notwithstanding, the Gujarat government has dreamt up a mega dam project across the Gulf of Khambhat, to trap the waters of 12 rivers that flow into the Gulf of Cambay and create a huge freshwater reservoir. Supposed to end all Saurashtra's water problems, the project is called Kalpasar (after a magical wishing lake of local lore).

Kalpasar's dam (64.16 km long and 35 meters wide) will connect Ghoga in Bhavnagar district of Saurashtra and Hansot in Bharuch district of South Gujarat and harness the Sabarmati, Dhadar and the rivers of Saurashtra. It will store about 16,791 million cubic meters (mcm) of water and annually provide for domestic use (900 mcm), irrigation (5,891 mcm) and industries (500 mcm).

Of the many concerns that emerge with the starting up of any such project -- structural aspects, environmental impact or potential disasters -- the fundamental issue is to supply safe drinking water, which will depend on the sustainability of the reservoir. And for Kalpasar, this will depend on three major parameters: the fresh water inflow, silt in the reservoir and the load of pollution the reservoir will be exposed to.

Dam-centric development With an ever-changing quality of catchments and rainfall pattern, it's difficult to estimate the water flow with absolute certainty. The dam dependency in state policy has already reduced water flow in the major rivers. Now the Narmada, from which the Kalpasar reservoir is expecting the largest amount of fresh water, is also going to have more dams -- 3,200 of them -- under the Narmada Valley Project. As it is, the amount of water that will be released from Sardar Sarovar downstream is doubtful. Nor is the picture any different with the Sabarmati and other rivers. Estimates and outcomes inevitably vary: Malprabha was to yield 1,338 mcm but came to only 878 mcm, while the Bhadar's flow is 93.79 mcm, instead of an expected 161.60 mcm.

The silt heap According to the Central Board for Irrigation and Power (cbip), the annual rate of silting from a unit reservoir is two to three times more than the initial assumptions at the time of project design. The Central Water Power Research Station (cwprs) estimates that the Narmada alone discharges about 68 million tonnes of sediment per annum into the gulf, while Mahi and Sabarmati together discharge about 20 million tonnes of sediment per annum. Over time, this gets dispersed over the whole of the gulf, but with the dam, it will be confined within the proposed dam area, resulting in a rise in seabed levels. The pre-feasibility study of the Kalpasar project has estimated a total sedimentation load of 51 mcm per year into the freshwater reservoir. So if it follows the trend of the big dams in India, in just 25 to 30 years, the reservoir will be full of silt.

Waiting in the wings to pollute Kalpasar further are domestic sewage, industrial effluents and agricultural run-off within the river basins. In 2000, 64 per cent of all the Class- i cities and 75 per cent of the Class- ii cities of Gujarat state were located along the three major river basins of Mahi, Narmada and Sabarmati. In 2005, about 20 million people live within the catchment area of the proposed Kalpasar reservoir. It's still not clear how much of the sewage from this area is treated.

Chemicals reservoir Gujarat is also the second largest producer of chemicals in India and the second largest state for total industrial investment. The gpcb and the Department of Industries and Mines (doim) say 8,000 industries are located in the contributing catchment of Kalpasar. These manufacture dyes, petrochemicals, pharmaceuticals, fertilisers and textiles. Rivers and streams (Khari, Sabarmati, Mini, Damanganga and Par) within the catchment area of the proposed reservoir already bear the brunt of non-compliance to effluent discharge standards. Agricultural runoff dumps a huge amount of total nitrogen and total phosphorus (from chemical fertilisers and pesticides) into Gujarat's waters. State policy of low canal water tariffs and subsidised (groundwater) irrigation facilities aggravate the situation. The reappraisal report on Kalpasar estimates that alarming levels of pollution will enter Khambhat within the proposed site of Kalpasar by 2050.

While the Gujarat government is elated now, it needs to look at project risks to derive optimum benefits.

Subhrangsu Goswami is a research associate with the Centre For Development Alternatives, Ahmedabad

Subscribe to Weekly Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.