GUWAHATI, Jan 18 � Noted dam expert Prof Nayan Sarma has suggested that the Lower Subansiri Hydroelectric Power Project (LSHEP) should be converted into a multi-purpose one to allay the fears of the people living in the downstream areas, besides meeting their water requirement for various purposes.
Speaking to The Assam Tribune, Prof Sarma, the present Head of the Department of Water Resources Development and Management, IIT, Roorkee said that the project should have the provision for flood cushioning and it should not disturb the normal flow of the river.
Prof Sarma is also associated with the designing of 26 small and large dams in India and abroad and also a member of the Indian Standard Code on Dams and Spillways of the Bureau of Indian Standard for the past 15 years. He was making his own observations on the LSHEP, which has now led to a serious controversy over its mono-type (exclusively generating power) and safety parameters.
He suggested that a piano-key weir type barrage should be constructed at a suitable site downstream of the LSHEP on the Subansiri to create a permanent backwater zone. Such a structure, with un-gated spillways, may also be constructed on the dam to facilitate creation of some flood cushioning space below the maximum water level (MWL). This will afford the flood control benefits to the downstream people, along with the flood dykes on both banks of the river.
The piano-key weir is hydraulically efficient with the established advantage of flood discharging capacity two to four times more than that of the conventional spillways proposed in the LSHEP dam. Furthermore, a significant amount of expenditure, in the form of both capital and recurring, could be saved by eliminating the steel gates with this structure.
Further, two irrigation canals should be laid along both the banks of the river from the piano-key weir barrage located downstream of the dam, to help irrigating the fields throughout the year. Thus the LSHEP can be transformed into a multi-purpose project, benefiting the downstream people economically as well as sustaining the aquatic fauna like the dolphins and Mahseers of the Subansiri, said Prof Sarma.