Stochastic operation analysis of irrigation reservoir in low-flow conditions: a case study from Eleviyan Reservoir, Iran

In Iran, an arid and semiarid country, the distribution of precipitation is irregular and uneven, making the replenishment of reservoirs difficult during periods of scant rainfall. In this paper, a method has been devised to make available the maximum amount of water for irrigation, drinking, and the flow regime of Sofi Creek. The optimal performance of the Eleviyan Dam was evaluated based on reservoir inflows. Before the construction of the dam, 21 years of flow data (October 1973 to September 1994) was measured, and possible low flows were calculated. In this study, 2 scenarios are considered; the first scenario is based on the assumption of an initially full reservoir, and the second is based on the assumption of full dead volume in addition to drinking and utility water. In the first scenario, system shortages were observed in September at all confidence levels and in August at 80% and 90% confidence levels. In the second scenario, considerable shortages were observed in September at all levels, and in August with a 70%–90% and July with a 90% confidence level.