Experts question Almatti dam height rise
Why is the height of the Almatti dam in Karnataka being raised in an extremely seismic zone from the current 519.6 metres to 524.5 m, allowing it thereby to store an additional 130 tmc of water?
Questioning the decision of the Krishna Water Disputes Tribunal (KWDT) given in mid-December 2010, Prof. T. Shivaji Rao, director, Centre for Environmental Studies at the Institute of Science, Visakhapatnam, has shot off a letter to several state heads, including Maharashtra chief minister Prithviraj Chavan, faulting the lack of data supplied by the Central Water Commission (CWC) on the adverse impact of backwater levels on both villages and cities of Maharashtra.
Computer simulation studies by scientists working under Prof. Rao highlight the probability of the dam bursting and flooding large tracts of Telangana in Andhra Pradesh and Karnataka. Backwater flooding would adversely affect the cities of Sangli, Kolhapur and Satara and neighbouring villages, Prof. Rao warns.
“Dam bursting can occur due to extreme floods, earthquakes, insufficient spillway capacity and foundational and construction defects or even human failure as happened when the gates to discharge peak floods in Srisailam dam in October 2009 were not opened in time,” he said.
Accusing the CWC of supplying an inaccurate dam break analysis, Prof. Rao has said that only recently an RTI has led to the CWC being ordered to supply their backwater curve and dam break analysis to the general public.
Acknowledging the letter, Mr Chavan, who himself has a scientific background, has expressed concern over the decision to raise the height. He admitted to being “disappointed with the decision”. Dam failing is a reality, with three dams having failed in Andhra Pradesh in the last five years. These were the Subbaraya Sagar in East Godavari in 2010, Pallamvagu Dam in Khammam in August 2008 and the Gundlavagu Dam in Warangal district in 2006.
“These dams collapsed due to poor construction and improper design. A large portion of the Almatti dam comprising 405 metres is an earthen portion. In all, 50 dams built post-Independence have failed so far, including the Kodaganar dam in Tamil Nadu, Nanaksagar dam in Punjab and the Machhu 11 Dam in Gujarat,” Prof. Rao said.
The KWDT has given three months to the state and Central governments to respond.
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