“…The threedimensional, variable-density flow code VARDEN, developed by the U.S. Geological Survey [Kuiper, 1983[Kuiper, , 1985, was used because it meets the objectives of our study: analysis of steady state, variable-density hydrodynamics at a regional scale. VARDEN has been used to simulate regional variable-density flow in the Gulf Coast aquifer system [Williamson et al, 1990] and in the Palo Duro Basin of Texas [Kelley, 1989].…”