Sensitivity analysis and research of hydraulic characteristic parameter and observation wells during the pumping test

Since there are many uncertainties in the state of groundwater, after determining the research direction and objectives, a numerical model should be established by means of simulation to analyze the hydraulic characteristics such as transmissivity and storativity in the research area. Sensitivity analysis is carried out effectively, and the optimal pumping test strategy is designed based on it. In many previous studies, the sensitivity map made by the two-dimensional model was used to discuss the sensitivity. However, after a long period of data accumulation, it was found that although there would be a continuous change in the discharge, the pumping well and the vicinity of the observation well's hydraulic gradient did not change significantly. From this we get an inference, that is, we cannot obtain the exact location of the sensitivity source in space by simply using a two-dimensional sensitivity map, at most, only the average parameter value of the active area can be obtained. In addition, most of the current research is based on the assumption of homogeneous steady-state conditions, but groundwater mostly exists in the form of heterogeneous transient state in nature. Therefore, this research hopes to use the method of inverse calculating the heterogeneous field to plan and use the developed software (VSAFT2 and VSAFT3) for effective 2D and 3D space simulation, so as to use the characteristics of the three-dimensional space concept to confirm various information and extend the discussion of the source. This will have a great contribution to the changes of water bodies in the future analysis area, groundwater recharge patterns and diffusion control of underground pollution.