In Reply Refer To: November 17, 1987 WGS-Mail Stop 411 OFFICE OF GROUND WATER TECHNICAL MEMORANDUM NO. 88.01 Subject: PUBLICATIONS--Release of two new reports documenting numer models The two subject recent reports are: 1. Lappala, E. G., Healy, R. W., and Weeks, E. P., 1987, Documentat computer program VS2D to solve the equations of fluid flow variably saturated porous media: U.S. Geological Survey Wa Resources Investigations Report 83-4099, 184 p. 2. Lefkoff, L. Jeff, and Gorelick, Steven M., 1987, AQMAN: Linear quadratic programming matrix generator using two- dimensiona ground-water flow simulation for aquifer management modelin U.S. Geological Survey Water-Resources Investigations Repor 87-4061, 164 p. The report by Lappala, Healy, and Weeks (1987) documents a numerical model that simulates isothermal, two-dimensional movement of liquid variably saturated porous media. The mathematical model of this phy process is developed by combining the law of conservation of fluid m a nonlinear (partially saturated) form of Darcy's law. The resultan mathematical model, or flow equation, is written with total hydrauli as the dependent variable. This allows straightforward treatment of in which part of the domain is saturated and part is unsaturated. I the model can simulate "difficult" nonlinear problems, such as those by infiltration into dry soils and by discontinuities in permeabilit porosities. The numerical features are such that the model can analyze transient in one and two dimensions with planar or cylindrical geometries. No boundary conditions treated by the code include infiltration, evapor and seepage faces. Extractions by plant roots is included as a nonl term. The report by Lefkoff and Gorelick (1987) documents the computer program AQMAN. The purpose of AQMAN is to determine the distributio pumping and/or recharge that minimizes or maximizes a management obj subject to constraints. The computer program AQMAN provides a link a modified version of the two-dimensional ground- water flow model of Pinder, and Larson (1976) and any standard Mathematical Programming input format. AQMAN uses the modified Trescott model to solve the basic ground-water flow equation to determine aquifer responses to both the stresses that cannot be controlled because of physical limitations or legal or socio- economic demands (the unmanaged stresses) and to the stresses that can be controlled (the managed stresses). The program, AQMAN, creates the input files to be used by an optimization program. These input files contain all the hydrologic information and managemen objectives needed by an optimization program to solve the management problem. AQMAN is written to handle either a linear or quadratic objective function. Various types of constraints can be defined for pumping and/or recharge rates and on ground-water heads, gradients, and velocities. One copy of each report is being sent under separate cover to all District offices, State offices, and some Subdistricts. Eugene P. Patten Chief, Office of Ground Water WRD Distribution: A, B, S, FO, POPUBLICATIONS--Release of two new reports documenting numer models