Study On Infiltration Recharge Of Beitang Reservoir To Groundwater

In an attempt to summarizing the previous work, and analyze the hydrometeorological, geological and hydrogeological condition of Beitang reservoir, in Tianjing city, the hydraulic conductivity (K) of the reservoir bottom stratum and its spatial random distribution were determined by using field hydro-geological investigation and grain size analysis in the laboratory. The field investigation shows that clay and silty clay are the main component in the bottom stratum of Beitang reservoir, with some silt and fine clay lens also contained. The K of silt and fine clay which appeared in the northcentral part of reservoir bottom area is 10^-4～10^-5cm/s, and its higher permeability is the main factor of leakage loss. The K values of Clay and silty clay are less than 10^-5cm/s but most about 10^-10cm/s. The laboratory analysis shows that it's feasible to use grain size analysis test to determine K of the reservoir bottom stratum and the Kriging method is the most impersonal way to show the contour of K. This study also concludes that the spatial random distribution of K in Beitang reservoir bottom stratum is more of logarithmic normal distribution than normal distribution and this conclusion provides the foundation for the later research of K's spatial variability.The interaction between the reservoir and groundwater was analyzed based on the groundwater regime data from observation wells which were set up in this research. By so doing a conceptual risk management system of water in Beitang reservoir polluted by ground water was established and it is possible to formulate a policy in favor of reservoir water quality by comparing the recharge or discharge relationship between reservoir and groundwater.At last, the leakage of reservoir was estimated by using Darcy Law. The average leakage of reservoir is 1 385.08m³/d, that is 50.56×10⁴m³/a, annual leakage loss covers 1.26% of total reservoir volume which value is 3 977×10⁴m³.