Aquifer Parameter Estimation of Transient Pumping Test Based on Analytical and Numerical Methods

The aquifer parameters are the necessary basis data for calculation of groundwater resources and prevention of groundwater pollution, therefore it is necessary to invert the parameters with numerical method. According to the standard of 1:50 000 hydrogeological survey, two pumping tests with single pumping well in deep aquifer and two pumping wells in shallow aquifer were conducted at Fuxing Water Works at Yanglinwei Town of Xiantao City in Jianghan plain. The theory of first kind of leakage system was adopted to estimate the parameters in deep aquifer. For the shallow aquifer, a comprehensive well function was derived and the parameters were obtained by using the special type curve matching method and straight line method. In addition, the FEFLOW software has also been used to develop a numerical model for the pumping tests. The parameters were also estimated by the numerical model associated with the pumping test data. The results indicate that the hydraulic conductivity and the specific storage coefficient of the shallow confined aquifer are 21.66-54.00 m/d and 1.28×10^-5 to 8.00×10^-4 m^-1, respectively. The hydraulic conductivity and the specific storage coefficient for the deep confined aquifer are 1.27-7.00 m/d and 3.90×10^-6 to 5.00×10^-6 m^-1, respectively. The leakage from the third aquitard layer is significant, which should be taken into account for the analysis of the pumping test. In this paper, the numerical model is developed to estimate the aquifer parameters associated with the pumping test data, the structure of the aquifer was considered in detail in the numerical model. The good agreement between the simulated results and the measured data indicate that the results obtained from the numerical simulation are reliable.