Foreign experts suggested dams on Brahmaputra to control floods

 GUWAHATI, April 25 – Many foreign experts visited the State to advise the government on the flood and erosion-related problems in the 1960s and 1970s. They differed in their suggestions that included measures ranging from a reconnaissance study for determining the magnitude of the flood problem, hydrologic and economic features of the Brahmaputra basin to construction of dams for flood control and power generation.

BP Bellport, Chief Engineer, US Bureau of Reclamation and Dr Ian Barton separately visited the State in 1965. Bellport recommended that a reconnaissance study to determine the magnitude of the flood problem and hydrologic and economic features of the Brahmaputra basin should be undertaken. He suggested that the survey should not include the study of water resources alone, it should also make an effort to determine the feasibility of constructing dams on the tributaries of the Brahmaputra.

Dr Ian Barton observed that any erosion control benefit by constructing storage dams on the Brahmaputra and its tributaries will be very small. Embankments already constructed have been effective in preventing large flood damage, but their susceptibility to breaches makes them partially successful in controlling floods.

He maintained that construction of dams for flood control purpose only cannot be justified. They should be built for both flood control and power development. Moreover, the problem of earthquake and large silt charge in the rivers will have to be taken into account in the design of multipurpose storage schemes. This silt load in the rivers can be reduced by taking up proper watershed management.

In 1966, HE Weller of the US Corps of Engineers made a detailed study of the erosion problem on the Brahmaputra and also considered the observations made by the Study Group on the Erosion Problem on the Brahmaputra, which was set up by the government in 1964.

In his report Weller suggested that the most desirable plan for controlling the Brahmaputra is its complete stabilisation. To accomplish this, sufficient reservoirs should be constructed to reduce sediment input and halt the aggrading tendency of the river. The river could then be confined to a single channel, trained into a series of easy bends, preferably along the main channel, by all methods of channel stabilisation.

He also observed that if dredging is judiciously applied, it can, in many cases, divert the river away from the problem areas. A careful study of the river trends is, however, necessary for this type of work, he said.

In 1970, at the request of the Union Government through the US AID for technical advice on mitigation of flood damages caused by the Brahmaputra, WA Stuff and HE Weller suggested that the Brahmaputra Flood Control Commission should prepare a framework plan directed primarily towards flood control and related drainage and bank erosion problems.

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