GUWAHATI, Jan 17 � The Lower Subansiri Hydroelectric Power Project�s (LSHEP�s) dam needs a pseudo-static analysis and a dynamic analysis to allay popular fear about its safety. This is to be done by adopting peak ground acceleration (pga) as approved by the National Committee on Seismic Design Parameters of the Central Water Commission of India.
This is the observation made by leading dam expert of the country Prof Nayan Sarma, the present Head of the Department of Water Resources Development and Management, IIT, Roorkee. Prof Sarma was associated with the designing of 26 small and large dams in India and abroad. He is also a member of the Indian Standard Code on Dams and Spillways of the Bureau of Indian Standard for the past 15 years.
Speaking to The Assam Tribune, Prof Sarma said the above analyses should be done to reaffirm the safety of the dam during the worst possible earthquake. However, he maintained, the exercise should be carried out by the competent and highly experienced institution.
If the above analyses require the dam to be strengthened, then appropriate steps should be taken to strengthen it, preferably by adopting roller-compacted concrete technology, he said.
He also suggested an appropriately designed piano-key weir type barrage at a suitable site downstream of the LSHEP on the Subansiri to create a permanent backwater zone so that the required water depth of the river is available for ecological purposes and the minimum level in the groundwater table is maintained with the basic water flow.
On both banks of the river, flood dykes should be constructed to prevent any inundation. Jack Jetty systems should also be installed on both the banks to check bank erosion and to channelize the river.
Besides, to ensure optimum success from the above measures, the reservoir operation schedule should be optimised on the basis of computer simulation study, said Prof Sarma.
