Multipurpose Projects Serve as a Flood Controller- Is this the Reality? A Study of DVC Projects of the Damodar River of West Bengal, India

Abstract

The river valley projects with many objectives are called multipurpose project. Among the single purpose dams, dams serves as follows: irrigation, hydropower, water supply, flood control, recreation, navigation and fish farming. Most of the cases, flood control is becoming the sole factor for which the multipurpose projects or dams can be constructed. The Damodar River was renowned as the “River of Sorrow” for its high magnitude and frequency of flood. The Damodar Valley Corporation (DVC) was modelled to play a major role in reducing the magnitude of flood by constructing several Multipurpose Projects in this river valley on this river itself and its tributaries also. To find out whether dams are able to control the floods or not in Damodar River basin, recurrence interval has been calculated through flood frequency analysis in two different periods: the Pre-Dam (1934-1957) and the Post-Dam (1958-2007) Period. Annual stream flow has been reduced in the post dam period. Discharge of the Damodar River has also been reduced in different Recurrence Interval years (5, 10, 20, 30, 40, 50 years) in the post-dam period. The ranges of flood moderation between the pre and post-dam period is high in the high recurrence interval years and vice versa. The major achievement of the DVC dams is these can moderate the flood up to 64% in the post-dam period. Flood moderation can reduce high magnitude of flood in the peak flow season. The major dams of the Damodar River valley of the DVC project can able to moderate or reduce high magnitude of flood of the river valley, but this can lead to increase in the frequency of low level flood. Dams are interlinked with the people and landscapes of the Damodar Valley region and the people can adopt and sustain with the vulnerable nature of the river.

Keywords:Multipurpose Project, Flood Controller, Flood Frequency Analysis, Recurrence Interval, Damodar Valley Corporation (DVC), Pre-dam, Post-dam, Flood Moderation