The Sardar Sarovar Dam located in Kevadia Colony in Narmada district is the lifeline of both Gujarat and Madhya Pradesh. Unlike last year, this year the dam reservoir is at a comfortable level at 119.51 metres — sufficient to provide the state with drinking water for an extra month until July end. However, the notice prohibiting farmers from drawing water from the main canal since this March has farm activists protesting.
A recent Central Water Commission report warned about Gujarat facing a 33 per cent deficit as far as water in reservoirs are concerned. In Gujarat all 10 reservoirs are showing a downward trend in water levels this year as on May 16. The advisory has recommended states facing drought to use water only for drinking till dams are replenished.
Is this why farmers are not being allowed to draw water?
Unlike most other dams, Sardar Sarovar is an interstate dam. The water level and the live storage available on any particular day is not as significant as Gujarat’s annual share in the basin. This dam has been built to supply water to Gujarat, Rajasthan and Maharashtra. The level of water therefore is to be read in the context of Gujarat’s share of the waters in a water year — July 1 to June 30. Officials say it is a misconception that the rising water level indicates the actual share that Gujarat can use. According to the policy of the Narmada tribunal, the dam will not provide water for irrigation during the summer.
How is this share calculated?
Narmada Dam is the first and classic case of integrated river basin planning and development where the entire Narmada river has got number of dams constructed over. Regardless of whether the water is stored in the Sardar Sarovar Dam in Gujarat or in Indira Sagar in Madhya Pradesh, it has to be shared in the ratio which has been decided by the Narmada Water Dispute Tribunal. Gujarat gets 9 Million Acre Feet (MAF) in a normal year when the basin fills up to its capacity of 28 MAF, Rajasthan gets 0.5 MAF and Maharashtra gets 0.25 MAF. The tribunal has assessed this figure of 28 MAF at 75% dependability. It means that once in four years can be a distress year and the states have to be prepared for it.
After four months of water year ending, that is July, August, September and October– which is the rainy season–the Narmada control authority makes an assessment of the availability of water. And then it decides that this much water is available and it will be proportionally shared between party states.
Is 9 MAF enough to fill the maximum capacity of the reservoir?
One acre-foot is about 1.24 lakh litres of water. Out of the share of 9 MAF in a normal year, the evaporation losses will be around 0.5 MAF. The dam also has to release water downstream to maintain the ecology. Officials peg the annual need at about 11MAF in the dam. However, even if the dam is filled at Full Reservoir Level (FRL), which is 138.68 meters after the gates were closed in 2017, the live storage capacity of Sardar sarovar is 4.75 Million Acre Feet. So, out of the total annual requirement of the state, the dam can hold just about 45% water even if it is 100% full. So, as officials say, "one should not get carried by the water level" as the dam almost never fills up to 100%.
The Sardar Sarovar Dam is in the shape of a trapezium and not rectangular, which widens at the top so that more water can be stored in it as it rises.
The last time Gujarat received 9 MAF water was two water years ago. The tribunal has also decided that in any year whenever there is surplus water that also has to be shared in the same ratio. The estimate also goes on changing as per the availability in the basin.
What is the share awarded to Gujarat in the current water year?
Gujarat was awarded 6.6MAF as per the last meeting of the Regulatory council of the Narmada Control Authority. However, 0.20 MAF of this share was returned to Rajasthan, which had parted with its unused share of the same volume last water year when Gujarat was in grave deficit.
What does it mean to return another state’s water share?
Just like the four states share good rainfall water, the tribunal also has laid down that in a distress year, the deficit also has to be shared amongst the party states in the same ratio, regardless of which state faces a rain deficit in a water year. Annually the total availability is assessed and the water is shared in the predefined ratio.
Last year, the total available water was assessed at 15.74MAF as against 28MAF in the basin and Gujarat received a share of 5.06MAF in water year 2017-18. At the end of the year, Gujarat ended up using 5.41 MAF. So 0.35 MAF was an excess withdrawal, which the state was constrained to draw from the dead storage. This year’s assessment is better than that. So, in the first initial assessment, it was assumed that it will be around 22 million acre feet. Gujarat officials were therefore hopeful to get 7 million acre feet. Out of this, the state returned 0.20 million acre feet of water of Rajasthan’s unused share from the last water year. The remaining 0.15 MAF, Gujarat will have to compensate in the form of power or money to MP and Maharashtra in the current water year.
With the riverbed power house shut for over two years, how does Gujarat intend to pay the other two states?
Gujarat is yet to settle accounts with Maharashtra and MP. The national water policy gives priority to drinking water and then irrigation and the least of all to hydro power generation. Therefore, it is also calculated that the water will only continue to reduce in the coming years, making power generation difficult.
How much out of the allotted share this year has Gujarat already used?
Out of the 6.6 MAF water awarded by the Narmada Control Authority, Gujarat has utilised about 6.23 MAF. The 0.20 MAF of Rajasthan’s share was deducted up front. Last year, Gujarat used 5.41 MAF in the entire water year. With still one and half month to go for the end of the water year and also keeping in mind the fact that monsoon could be delayed. Until that time, the state has to ensure drinking water security, thus prohibiting farmers from drawing water from the canal.
How has the dam received steady water supply from MP since September this year?
The water being released by MP is towards the share that Gujarat must receive or because they are generating power which makes them duty bound to release water to Gujarat because MP has a 100% share of its independent power projects. Whereas Gujarat’s power generation as well as water is part of inter-state sharing.