Documentation of revisions to the regional aquifer system analysis model of the New Jersey coastal plain

Abstract

The model, which simulates flow in the New Jersey Coastal Plain sediments, developed for the U. S. Geological Survey Regional Aquifer System Analysis (RASA) program was revised. The RASA model was revised with (1) a rediscretization of the model parameters with a finer cell size, (2) a spatially variable recharge rate that is based on rates determined by recent studies and, (3) groundwater withdrawal data from 1981 to 1998. The RASA model framework, which subdivided the Coastal Plain sediments into 10 aquifers and 9 confining units, was preserved in the revised model. A transient model that simulates flow conditions from January 1, 1968, to December 31, 1998, was constructed using 21 stress periods. The model was calibrated by attempting to match the simulated results with (1) estimated base flow for five river basins, (2) measured water levels in long-term hydrographs for 28 selected observation wells, and (3) potentiometric surfaces in