Estimate of time required for environmentally friendly flushing in dez dam reservoir

Environmentally friendly flushing aims to send only the concentrations of the sediment that the environment can withstand. In this study, the time required for environmentally friendly flushing in Dez dam reservoir was esti-mated. For this purpose, the relationship between the concentration, duration, and scale of the severity of ill-effect for fish was considered. A study was conducted on Dez dam reservoir in Iran, where the average historical outflow from the dam, and the volume of sediment flushing was evaluated. According to this study, the dam is facing a serious sedimentation problem. Its dead volume is presumed to be quite full in the coming 10 years. Performing flushing operations through the three irrigation gates of the dam has received much more attention in recent years as compared to the past. The results from this study help us to determine the appropriate hydraulic conditions to decrease the negative environmental effects of Dez dam flushing operations on the downstream ecosystem. © IWA Publishing 2015.