A new method for the identification of distributed transmissivities

For two-dimensional groundwater flow in an isotropic confined aquifer, it has been shown elsewhere that two independent steady state sets of data, ie, piezometric heads and source terms corresponding to different steady state flow conditions, and the value of transmissivity at one point suffice to determine transmissivity uniquely in a connected domain. The data are independent if the hydraulic gradients are not parallel anywhere over the domain. The applicability of this technique to real cases is tested with two synthetic examples. The fit is good. The relative error for the identified internode transmissivities is very low when error-free data are used, and it varies by an amount approximately constant over the entire aquifer when an error on the initial value of transmissivity is introduced. The errors on the piezometric heads bear more relevance, but nonetheless, the affected results are still good. -from Authors