YIELD MODEL FOR SCREENING SURFACE-WATER AND GROUNDWATER DEVELOPMENT

An optimization model is developed for selecting between candidate surface-water reservoirs and ground-water development. The model may be used to perform a preliminary screening of alternatives for water-supply development, and to identify storage capacities at reservoir sites, as well as aquifer pumping at candidate locations. A hybrid simulation-optimization strategy is used to consider monthly operation of the reservoir and aquifer system using historical or synthetic hydrologic data. A modified sequent peak algorithm is used for reservoir sizing, and a unit response matrix approach is used to model the ground-water subsystem. A target aggregate firm yield from the surface water-ground water system may be specified. Decisions on the failure of firm yield at each reservoir site during a critical period for streamflow, with a corresponding increase in ground-water pumping such that the system firm yield is maintained are considered. Example applications with data from the Jordan River basin in Utah demonstrate the utility of the model relative to a disjunctive analysis of surface water-ground water development.