Research On Flood Control Limited Water Level Regulation Of Xingxingshao Reservoir And Analysis Of Its Influence On The Groundwater Recharge In Downstream Area

In the north of China, water resources shortage is especially serious because of the shortage and heterogeneity of precipitation. With the increase of China population and the development of society and economy, the amount of water resources utilization and polluted water have been rising while the environment quality is deteriorating. This situation has become a main constraining factor of national social-economical sustainable development. Therefore, flood water utilization is of great significance for relieving the crisis of water resources shortage and improving the environment quality which can be realized through fully excavation the potentiality of reservoirs storage based on scientific-technical advance while the flood control risk doesn't increase.For the safety of flood control, Xingxingshao reservoir keep a very low water level in flood season, the stored water is variously wasted, so that there is no water to store when reservoir inflow is deficient at the post-flood period. Then it isn't making the best of the part flood resources in flood season. The key to resolve contradiction on the risk and the benefit is rest with the reasonable adjustment of the flood control limited level. The flood control limited level is decided at the reservoir design and used until now. Owing to no consider the forecast scheduling, Xingxingshao reservoir put in practice the stage flood scheduling, but the flood control limited level of flood season also restrict the water storage in the post-flood season.An overall review of theoretic researches and scientific practices on adjustment & application of staged limited level of reservoir during flood season both domestically and abroad is drawn in this paper. Based on it, take Xingxingshao reservoir as research object, the factors of the nonstructural measures focusing on adjustment of flood control limited level, including design flood computations, the method of flood forecast scheduling, immigrant flowage line, reservoir sedimentation influence, the analysis of the flood control risk and benefit. The research is carried out emphatically from these six aspects. Furthermore, the influence of the groundwater recharge on the downstream area is qualitative analysis when the adjustment of flood control limited level of reservoir.Based on the analysis of the geographical features of Chaluhe basin, the characteristics and rule seasonal rule of the reservoir inflow by analyzing the precipitation characteristics and averaged annual ten-day inflow, it is necessary to adjust the flood control limited level for ensuring the probability of the reservoir refill. The key to reservoir refill at post-flood period is the flood control limited level of flood season. So that the Fisher Optimal Partition method, which belongs to clustering analysis method, is adopted to partition flood season. Then, a comparison of the calculated result with actual partition is made.Dispelling danger and reinforcing engineering of Xingxingshao reservoir is processing, the structural measures which influence water lever adjustment can be satisfied. Hence, the paper mainly discusses nonstructural measures for the adjustment of flood control limited level. By renewing the hydrologic data series by interpolation and extension, calculating correlated parameters by annual maximum values method, the new achievements of design flood are put forward by curve fitting method of frequency curve. Considering flood operation rules of the flood forecast and processing the flood regulation calculation according to the net precipitation, regulated water stage corresponding to upper water level for flood control can be ascertained. Considering the influence of the immigrant flowage line, then upper water level for flood regulation is compared with actual transfer elevation. Considering the difficulty of reservoir sedimentation quantitative analysis, the water lever for the flood regulation calculation can be depressed moderately. According to risk analysis theory, the regulative range of flood control limited lever can be analyzed and evaluated from the aspect of limited risk rate. Furthermore, reservoir economic benefit which comes from the adjustment of the flood control limited lever is considerable. From the viewpoint of nonstructural measures, the flood control limited level of Xingxingshao reservoir in season period should be adjusted at a level of 242.55 meter in theory.Reservoir elevation-storage relation is the key tache of the programmable reservoir flood regulation calculation. Genetic Programming, which is Optimal Searching technique derives from genetic arithmetic, is used to calculate the function relation between reservoir elevation and storage, between reservoir elevation and water-conveyance tunnel discharge, between reservoir elevation and draw-off tunnel discharge. Then the veracity of reservoir flood regulation calculation is improved.Based on the analysis of groundwater types, the conditions of groundwater recharge, runoff and discharge, groundwater level regime and groundwater development and utilization status in the downstream area of Xingxingshao reservoir, the two mainly factors, stream seepage recharge and irrigation escape recharge, is determined by contrasting the adjustment of flood control limited level, which influence the groundwater recharge capacity of downstream area. Based on the factors done above, the time and space diversity of groundwater recharge is qualitative analyzed, the recharge source come from the upland water which pass through the reservoir regulation. At last, many suggestions for developing and protecting the water resources are presented.An analysis has been made of the adjustment of flood control limited level of Xingxingshao reservoir, which can provide scientific help in assessing and demonstrating the adjustment of flood control limited level. Fully excavation the potentiality of reservoirs storage can provide with scientific foundation for the utilization of the rain and flood resources. It deserves to be further studied on the influence of groundwater recharge, because it not only provide help to the rational exploitation and effective utilization of the water resources, but also promote the economic development and protect the ecological environment.