Research On The Technology Of Groundwater Recharge And Utilization In Chaobai River Basin,Beijing City

The underground reservoir is an active and purposeful engineering measure to store, adjust and utilize groundwater resources. In particular, it can make use of surplus flood and water transfer to improve water shortage in arid areas and improve the utilization of water resources. According to the characteristics of water resources and water supply requirements of Beijing, it is necessary to build underground water reservoirs for many years to regulate water resources and to protect capital water supply.The South-to-North Water Diversion Project has greatly alleviated the water crisis in Beijing, especially through the joint regulation of water resources, which has eased the serious losses of groundwater resources over the years. However, it is worthwhile to study how to treat the tail water after the South-North Water Diversion Project to Beijing. In order to reduce the surface water evaporation and conserve the "water funnel" formed by long-term exploitation of groundwater, the tailings of the South-North Water Diversion Project may be poured into underground aquifers. In the process of groundwater recharge, the choice of site, the method of recharging and the determination of each parameter are the main factors influencing the effect of recirculation, and need to be analyzed and designed rationally according to the specific situation.In this paper, the Chaobai River Basin in Beijing is selected as the study area. The area is located in the middle and upper part of Chongbai River alluvial fan. The soil layer is coarse and rich in water. There are 8 water sources, Huairou emergency water source, Plant water source. As a result of years of over-exploitation, the formation of a large area of precipitation funnel, is the ideal storage space. On the basis of site investigation, the sand and gravel pits in Shahe and Yanqi rivers were selected as test sites for pit and irrigation, and infiltrated during flooding period of Dashuyu reservoir.In this paper, the data were collected from domestic and abroad. Test; radiation wells and large wells to reinjection test were Niuhe area and the North Xiaoying water color garden area for(cattle River area, a group of large-caliber wells, a group of radiation wells; North Xiaoying water color garden A group of large-diameter wells, a group of radiation wells). In the first place, according to the formula, theoretically analyzed theartificial recharge of the groundwater in the Chaobai River basin, and calculated the theoretical recharge amount. Secondly, through the test site selection, the related process selection and the recharging test design, Test program: sand and gravel infiltration recharging test, the radiation well test and large well wells backwater irrigation test.Finally, through the recharging test and on-site monitoring, the data such as the amount of recharge water, the head of the recharge water, the water quality monitoring data of the water level and so on were compared and analyzed, and the following conclusions were drawn:(1) The results of gravel pit infiltration test show that the groundwater level is increasing. The groundwater level in the near infiltration area increases first and then decreases, and the groundwater level in the far infiltration area increases slowly and gradually. As the ground water quality is better, better than the local groundwater quality,with the infiltration of infiltration time extension, the surrounding agricultural wells hardness, salinity content showed a downward trend. This indicates that if the water with good water quality is recharged in the proper position, it will not only help recover the groundwater resources with serious losses, but also play a certain role in improving Quaternary water quality.(2) Radiation well water level in a short period of time a significant rise, uplift and then began to reduce and gradually stabilize.(3) The water level of the large-hole well rises in a short period of time, and then the rate of water level increases slowly and gradually, and the amount of recharge has remained unchanged. Since the recharge source is local groundwater, the background concentration is similar to that of the test field. Before and after irrigation, the groundwater quality did not change greatly.The results show that the upper reaches of the Chaobai River is a good groundwater infiltration field, but the seasonal requirement of the recharge source is obvious when the recirculation project is carried out. Therefore, under short-term high-intensity recharge(to reduce evaporation losses) The method of ground infiltration and recharge by river channel and gravel pit is preferred. If there is a stable surface water source needs storage, the intensity is not large, and the water quality is high, then choose asmall footprint, suitable for planning the well irrigation method.