A Sustainable Approach for Flood Mitigation in Kokrajhar, Assam

Kokrajhar town is the headquarter of the Kokrajhar district as well as the headquarter of Bodoland Territorial Region (BTR) of Assam. BTR situated in the foothills of Bhutan and the northern part of the region faces common problems like flash floods, erosion, and crisis of drinking water. Many areas in Kokrajhar town submerge during the month of July–August every year. Prevention of urban flooding in Kokrajhar areas has become an important issue due to the hydrological impact on urban development. In this study, the author tried to investigate the causes behind the flood in the Kokrajhar town every year. Also, sustainable measures for flood mitigation in these areas have been chalked up. By physical survey, it is found that the existing drainage system of the Kokrajhar town is under construction and poorly maintained which led to the accumulation of stormwater or waterlogging. At present, the outfall points of the existing drains are on the Gourang River and the Tarang River through a major canal. Various hydrological factors are analyzed by ArcGIS. The stormwater drainage design works are proposed to be implemented in phases from the intermediate to future design period. A proposal for a drainage network has been made where there is no land available for constructing surface drainage. By monitoring the hydrological impact, the flow capacity of the existing drainage system is analyzed and compared with the proposed design drainage system.