Conjunctive water management{CWM)involves coordinating use of ground and surface water sources. Agricultural (A) and nonagricultural {NA)users compete for available water of adequate quality. A Simulation/Optimization (S/0) conjunctive water management model was developed to aid estimating the effects of water and environmental management decisions on crop yield and water quality. Included subsystems are groundwater, surface water, reservoir, delivery system, drainage, and A and NA water users. The nonlinear model addresses flows described by nonsmooth piecewise-linear functions which have discontinuous derivatives. Embedded constraints describe all significant subsystem flows. For example 1 deep percolation and runoff from surface irrigation are explicitly described as functions of furrow inflow rate. Solution involves quasilinearization and cycling. We apply the model to a study area representative of part of Salt Lake Valley, Utah. We use the E-constraint method to maximize irrigated crop production subject to constraint on leaching to groundwater. Tested scenarios demonstrate model capabilities for transient management
