AP rules out fresh survey on Polavaram for ‘backwater effect’ at 50 L cusecs

Vijayawada: As the Telangana government raises its concern over the ‘backwater effect’ due to the implementation of the Polavaram project on Bhadrachalam and at others places, Andhra Pradesh says there is no scope for a fresh survey.

“Three surveys have been already held based on directions from the Central Water Commission and there is no need for a fresh survey to gauge the possible maximum flood possibility of 50 lakh cusecs unless otherwise warranted,” the AP government has said.

Telangana water resources engineer-in-chief C Muralidhar wrote a letter to the chief executive officer of Polavaram Project Authority recently, expressing concerns over the backwater effect from the Polavaram project on Bhadrachalam town and other places. He called for another round of backwater studies by involving a neutral agency for a revised PMF of 50 lakh cusecs and for initiating protection measures against the drainage congestion vis-a-vis Kinnerasani and Murreduvagu rivers.

AP water resources authorities say the maximum flood received in Godavari river in the last 500 years was 28 lakh cusecs. In 1986, it was 36 lakh cusecs (at Sir Arthur Cotton barrage at Dowleswaram), against 28 lakhs cusecs in 2006 and 26 lakh cusecs in the recent floods.

They say that the Polavaram project dam’s height has been fixed at 45.72 metres FRL, based on an assessment that the maximum flood received is to the tune of 36 lakh cusecs only and the Polavaram’s concrete spillway has been designed to withstand floods upto 50 lakh cusecs, which is cited as a factor for safety.

The authorities say that three surveys involving Andhra Pradesh Engineering Research Lab in erstwhile AP, IIT, Hyderabad and a joint team of engineering from both AP and TS have been carried out on submergence areas of Polavaram project and these did not notice any major issue of concern over submergence.

The initial survey found the submergence area comprising 373 habitations in 272 villages at the 45.72 meter contour level.

Moreover, the AP government has taken up a Lidar survey (light detection and ranging), a remote sensing method used to examine the surface of the earth to find out the submergence areas. The processing and analysis of data are in progress and the details are expected to be out shortly to give a clear picture of areas of submergence due to the Polavaram project, AP officials said.

Referring to Telangana seeking protection against drainage congestion of Kinnersani and Murreduvagu rivers, the AP authorities say that such a situation could last for a few hours or a day when the water level in Godavari river is above the water levels in the two rivers. “Once the water level starts receding, the water from rivers joins the river water,” they said, referring to the study reports.

The AP authorities also raise concern saying that both Odisha and Chattisgarh have not conducted any environmental impact study on the submergence of their areas due to the backwater effect from the Polavaram project so far. This, even as the AP government has made it clear it is ready either to compensate or to strengthen their flood banks, keeping in mind the heavy floods witnessed at 36 lakh cusecs level.

If Telangana asks for a fresh study at 50 lakh cusecs of floods, both the states may ask for the same, causing fresh hurdles to the execution of the Polavaram project, it is pointed out.

An official from AP water resources department said, “Three studies have been carried out involving professional agencies. These found no major abnormalities on submergence due to Polavaram project, keeping in mind the heavy floods of 36 lakh cusecs. Now, seeking a fresh study in anticipation of a flow of 50 lakh cusecs of floodwater is unacceptable. It will encourage other stakeholders to raise similar demands and if so, this would result in a fresh delay in the execution of the project.”