Flood Risk Analysis Of The Reservoir In The Arid Area

Water resource is the material basis for human survival and development. With the economic and social development, the demand for water resource will become higher. At the arid area, the volume of water is insufficient and uneven distribution, and the runoff most concentrates in the flood season. Reservoir as important water project should utilize the flood adequately. But the flood risk analysis that includes the beneficial and flood risk must be done to ensure the reservoir safe.The predecessor's production were studied and consulted in this paper. Jahezi reservoir of Manasi River in Xinjiang was taken as an example to study the flood risk of the reservoir in the arid area.Jahezi reservoir is located at the northwest arid area of China, the primary tasks of which are flood control land irrigation. It has been reinforced in 2003 so the discharge capacity and the safety of dam were increasing at large degree, which created the conditions to utilize the flood sufficiently by raising the limited water level. The flood season of Jahezi reservoir was broken into spring flood season and summer flood season on the basis of the time of flood appeared. The summer flood season was subdivided into main flood season and post-freshet season by many methods such as the mathematical statistics method and fuzzy analysis method. The flood control risk in spring was analyzed by the qualitative analysis. The summer flood reason is the key period for reservoir controlling flood and achieving benefit because this stage is longer and the volume of flood is larger. The many proper limited water levels were study out through analyzing the engineering condition and safe operation instance of the reservoir; the stochastic simulation method and frequency analysis method were adopted to calculate the flood control risk rate of reservoir at the different limited water levels. We can learn from the result that adopted the different limited water levers in flood season could raise the benefit of reservoir but not increasing the risk of reservoir at the same time. The risk rate of flood control will increase if the limited water level is raised, but the increased flood control risk will not very large at frequent flood owing to the discharge capacity of reservoir is larger. At last the fuzzy analysis model that consider on the flood control risk of reservoir and benefit was formulated and a better flood limit water level was chosen.