Transient Hydraulic Tomography and Tracer Tomography (Paperback)

Detailed spatial distributions of hydraulic parameters are imperative to improve our ability to predict water and solute movement in the subsurface. Transient hydraulic tomography (THT) is a cost-effective technique for characterizing the heterogeneity of hydraulic parameters in the subsurface. In this study we developed an efficient sequential successive linear estimator (SSLE) for interpreting head data from transient hydraulic tomography to estimate three dimensional hydraulic conductivity and specific storage fields. We first analyzed the cross correlation between transient head data and hydraulic parameters and covariance of transient heads using a hypothetical one dimensional aquifer. This analysis led to an efficient way to interpret transient heads. To more efficiently interpret the transient head data, we developed an estimation approach that utilizes the zeroth and first temporal moments of well hydrographs, instead of drawdown itself. We further extended the hydraulic tomography concept to tracer tomography and combine hydraulic/tracer tomography for characterizing NAPL (Non-aqueous phase liquid) source zones.