Simulation models of groundwater basins require that values be given for geohydrologic parameters such as permeability and storage capacity. In present practice these parameters are initially estimated and later adjusted by trial and error to improve the ability of the model to simulate some known portion of the water history. It has been suggested that this process might be reversed to deduce geohydrology directly from the historical record. This suggestion was tested against a basin studied earlier by the California State Department of Water Resources. The fitting criteria used gave rise to linear programing formulations, which were solved from the basin data. The approach shows promise in that about one‐third of the basin parameters were evaluted, but further development is required. It is believed that historical records, although apparently overdetermining the system of equations, actually underdetermine the system because of redundancy effects. The approach appears to offer the best known method for estimating the effective aquifer depth.