Impact of interbasin transfer hydroelectric project on downstream aquatic habitat

Abstract

The recent surge of anthropogenic activities like damming is causing a severe threat to the aquatic ecosystem. A scope of minimizing the degradation of biota exists by modifying the dam operation policy. This can be achieved by releasing a minimum environmental flow (EF), which further requires more scientific investigations. The present study investigated the impact of an interbasin transfer hydropower dam on the downstream habitat of an endangered fish species, Tor putitora, using an adaptive modelling framework. The framework consists of coupling a reservoir operation and a hydrodynamic model. This study analyses the scope of releasing different EFs from a hydropower dam to meet the environmental flow requirement (EFR) at downstream with satisfactory power production efficiency. The EFR was estimated using flow duration curve and Tennant's method. A lean period inflow hydrograph was incorporated into the model with a series of alternate EFs. Two scenarios were explored, with 4 and 6 h of peaking hours, along with the three cases of different initial reservoir storage. The total usable area over the river reach of the mentioned fish species was evaluated from the flow parameters simulated by the hydrodynamic component of the model. The power production efficiencies and area utilization rates were assessed in all these cases to prepare an easy‐to‐use decision support tool in a tabular form depicting the possible states of EF. The generalized methodology adopted in this analysis will help the decision‐makers quantify EF to be released from the dam within an acceptable power generation efficiency.