A simple data reduction method for pumping tests with tidal, partial penetration, and storage effects

Single-well and group-well pumping tests were undertaken in a deep gravel formation of the Taipei basin to determine the hydraulic parameters and better understand the drawdown characteristics across the basin. The periodic drawdown fluctuation due to tidal loading from the overlying river resulted in a difficulty in determining the hydraulic parameters by those conventionally used graphic techniques. In addition, many other site-specific influencing factors, such as the partial penetration effect and the large diameter of the wells, had to be considered. In this paper, a simple data reduction method was presented to resolve the above-mentioned complications. It was demonstrated that the drawdown data induced by group-well pumping were well predicted using the shifted drawdown curve deduced by the proposed method.