A Study on Flood Hazard Mitigation of Guwahati City

Abstract

The problem of urban flood of Guwahati, a city located in the northeast part of India, is one of the burning problems at present. The topography of the city is such that rainwater cannot drain out easily from the heart of the city. With rapid growth of residential area in the surrounding hills, sediment yield from the immediate upper catchment is increasing and deposition of the same in drains is adding another dimension to this problem. Therefore innovative planning and efficient design of the drainage network is necessary. An effort has been made to study finer details of the siltation process by investigating a small part of the drainage system. Theoretical analysis has revealed that for the existing cross section and bed slope, flow velocity in the drain should have exceeded the required scouring velocity to make the channel a self cleansing one. Thus, sedimentation occurs due to other factors. Possible factors responsible for sediment deposition have been analyzed and some remedial measures have been suggested. Scope of restricting sediment and water yield from the hilly watershed by implementing ecological management practices (EMP) has also been investigated and a concept of adopting optimal EMP has been suggested.