Kwankwai Daranond and Tian-Chyi Jim Yeh
The estimation of hydraulic properties is important in groundwater management and contaminant migration investigation. In this study, observed hydraulic heads at ten observation wells during pumping tests are simulated in synthetic aquifers using VSAFT2. This study employs the analytical solution and hydraulic tomography method (HT) to estimate T and S values of a homogeneous and a heterogeneous medium. The estimated values from the analytical solution is close to the assigned values in the homogeneous case but deviate from the specified values in the heterogeneous case. On the other hand, HT performs well in these two cases with the same boundary condition as specified in the forward model. However, the specified boundary condition has an effect on a parameter estimation, and it is difficult to define in the real world. Thus, this study also examines whether permeable or impermeable boundary can be detected in the inverse model by using drawdown data and initial guess of boundary condition. In particular, this study examines the effects of well network on the estimates of the boundaries and parameters.