Simulation Study for Minimizing Diurnal Variation of Flow in a Hydroelectric Project to Reduce Downstream Impact

Hydro-Electric project are generally operated as peaking plant. This induces diurnal variation of flow in the downstreams of the dam even in a run-of-the-river scheme. Lower Subansiri Hydel project, proposed on the Subansiri River of Assam, India, is one of the major Hydel projects of India. Reservoir Simulation Model has been developed with a prime objective to assess extent of flow variation in the downstream of the dam. The simulation study has revealed that during lean period the discharge in the downstrem increases significantly during the peaking hour and the flow discharge become almost zero during the non-operating period. While the high discharge may cause erosion and can create flood like situation, the low discharge may have several adverse impact like increase in pollutant concentration. Scope of adopting structural and non-structural measures for minimizing deviation of flow from its normal condition has been investigated and encouraging result has been found.