Hydrological changes and their impact on fluvial environment of the lower damodar basin over a period of fifty years of damming The Mighty Damodar River in Eastern India

Abstract

Abstract The Damodar River is one of the important tributaries of the Bhagirathi – Hugli (Ganges) river system. As the river flows just in opposite direction of rain – bearing monsoon wind, devastating floods were regular occurrences for which the river was famous as the ‘Sorrow of Bengal’. After Independence in 1947, to arrest the catastrophic floods, the Government of India constructed through Damodar Valley Multipurpose Project (DVP), a number of dams, barrage and diversion canals. The main aim of the present study is to trace out the hydrological changes that happened over a period of fifty years of the implementation of DVP on the mighty Damodar River in eastern India. It clearly shows the extent of man induced changes on river regime and their impact on fluvial environment. In the past due to unregulated free flow, the river Damodar opened a number of distributaries e.g. Behula, Kantool, Ghia, Kana Damodar etc. After the construction of four dams and a barrage, because of the massive diversion of upper Damodar water into canals, the lower Damodar is now starved of its natural flow of water. This resulted gradually either de-linking of some of the distributaries from the mother Damodar river and / or a few surviving distributaries turning into kana nadis (blind rivers). This is unique example of how human interference to natural drainage system has changed over the long past the hydrological conditions modifying life drainage into defunct one. Unfortunately, this created just the opposite reaction as instead of controlling floods, the lower Damodar basin is repeatedly devastated by man – made floods. Thus, the Lower Damodar segment shows a dynamic change from a turbulent, frequently overflowing river to now a timid, practically dying channel through human manipulation.