- Deccan Chronicle, August 17, 2006

Floods alter Polavaram plan

By A. SRINIVASA RAO

Hyderabad 

The State government is looking at redesigning the Polavaram dam on the Godavari river to enable it to withstand bigger floods and protect the temple town of Bhadrachalam downstream. The decision comes after the government vigorously defended the current design of the dam. This newspaper had reported that a slew of reports by experts had stated that the dam, as it is planned now, cannot handle floods beyond a certain volume. Sources in the department said the recent floods were an eye-opener. Officials are now planning for a situation where the Godavari river and its major tributaries like the Penganga, Pranahita, Indravati and Sabari flood simultaneously.

Last week, 28 lakh cusecs flowed down the Godavari. (A cusec is a cubic feet, about 28.4 litres of water, a second; 28 lakh cusecs means approximately 7.7 crores litres of watering flowing a second). The record was the flow of 36 lakh cusecs in 1986.

An environmental impact assessment report had indicated that the spillway of the dam was designed for a flood of 36 lakh cusecs based on

The State government is looking at redesigning the Polavaram dam on the Godavari river to enable it to withstand bigger floods and protect the temple town of Bhadrachalam downstream. The decision comes after the government vigorously defended the current design of the dam. This newspaper had reported that a slew of reports by experts had stated that the dam, as it is planned now, cannot handle floods beyond a certain volume. Sources in the department said the recent floods were an eye-opener. Officials are now planning for a situation where the Godavari river and its major tributaries like the Penganga, Pranahita, Indravati and Sabari flood simultaneously. Last week, 28 lakh cusecs flowed down the Godavari. (A cusec is a cubic feet, about 28.4 litres of water, a second; 28 lakh cusecs means approximately 7.7 crores litres of watering flowing a second). The record was the flow of 36 lakh cusecs in 1986. An environmental impact assessment report had indi-cated that the spillway of the dam was designed for a flood of 36 lakh cusecs based on the 1986 figure. According to the model, if the reservoir level is maintained at 140 ft above sea level (ASL) at Polavaram dam, the backwater at Bhadrachalam would be at 186 ft at ASL. During the current floods, the ASL at Bhadrachalam was 180 ft and water entered the town. The consequences would have been disastrous, the officials realised, if water at the future Polavaram dam reached 150 feet ASL Following suggestions from various quarters, the department officials are now rethinking on the design to withstand PMF of 45 lakh cusecs, assuming that all its tributaries and the Godavari are flooding at the same time.

As per the Godavari Waters Disputes Tribunal award in 1980 and the subsequent agreement signed with Chhattisgarh (which was part of Madhya Pradesh then) and Orissa, the design and flood discharge operation of Polavaram project would be looked after by the Central Water Commission. Therefore, the department would propose to the CWC on redesigning the project spillway based on the revised PMF of 45 lakhs. As an adjunct, the discharge capacity of Dowlaiswaram barrage downstream of Godavari river would have to be increased from the present level of 28 lakh cusecs to 45 lakhs, sources said.