Time-dependent Stochastic Hedging Rules to Reservoir Operation: A Case Study of the Bukan Dam Reservoir

In operation of dam reservoir, due to the possibility of severe water shortages in the future, supplying total demand of current step is not rational, and the use of hedging rules can provide insurance for water supply in the future. In the reservoir long-term operation to supply the irrigation water demand, uncertainty of reservoir inflow and uncertainty of irrigation water demand have a significant effect on release. Crop water stress sensitivity variation at different growth stages varies the crop production function slope, which is not seen in seasonal production functions. In this study, a stochastic planning model with time-dependent production functions and a deterministic planning model with seasonal production function, in operation of the Buchan dam reservoir by using hedging rules are compared. The results show the reservoir operation by hedging rules increases economic benefit by 46.8% compared to the existing operation model. The time-dependent production function can improve the results by 19% over seasonal production functions. Also, the results show using stochastic model with the inflow uncertainty, irrigation water demand uncertainty and both, inflow uncertainty and irrigation water demand uncertainty simultaneously, the economic benefit increase by 0.73, 4.95 and 12.99%, respectively.