Determination of Aquifer Parameters from Comprehensive In-situ Pumping and Tracing Test in the Multi-layer Monitoring Boreholes

A multi-layer groundwater level-water quality monitoring system has been developed to investigate the aquifer-aquitard system that is located from the bottom of 1st aquifer to the top of 2nd aquifer,across the saltwater-freshwater transitional zone in the North China Plain.Based upon those boreholes,a series of in-situ tests have been carried out such as the pumping test,slug test,as well as tracer test in different layers.The hydrogeogical parameters in the aquifer-aquitard system have been obtained using the analytical method and numerical simulation method.The results show that the hydraulic conductivity and the storage coefficient at the bottom layer of 1st aquifer are 4.320~7.550 m/d and 4.53×10-4~2.19×10-3,respectively,the hydraulic conductivity,the longitudinal dispersion,and the longitudinal dispersivity in the aquitard are 2.20×10-3~7.65×10-3 m/d,0.023~0.428 m2/d,and 0.010~0.051 m,respectively,and the hydraulic conductivity and the storage coefficient at the top layer of 2nd aquifer are 0.142~0.929 m/d and 4.53×10-4~2.19×10-3,respectively.