Reservoir operation and evaluation of downstream flow augmentation

The Stochastic Dynamic Programming model, which is outlined, was applied to derive the optimal operating policies of two proposed reservoirs on the Kali Gandaki and Burhi Gandaki Rivers in central Nepal, with an irrigation project located downstream on the Sapta Gandaki River that supplies water to 20,000 ha of agricultural land. The existing supply of irrigation water is not sufficient to meet requirements during the dry season. Optimization of the reservoirs was carried out only for maximization of electrical power, as the reservoirs have been proposed for power production. A generated inflow series was used in the simulation model to obtain modified flow downstream of the reservoirs, and the existing and modified flows were compared. Results indicated that, after construction of the two reservoirs, the supply of irrigation could be increased 20% without constraining reservoir operation.