Simulation/optimization modeling for water resources management

Many important advances have been made in the development of mathematical m odels for conjunctive water management and reservoir management. However, t he conjunctive use models that have detailed stream/aquifer system interact ions have not considered reservoir management rules. Conversely. reservoir management models have not simulated stream/aquifer interactions in detail. There is a need for enhanced linking of reservoir and stream/aquifer syste ms in conjunctive water management models. This paper presents a simulation /optimization model that integrates linear reservoir decision rules, detail ed simulations of stream/aquifer system hows, conjunctive use of surface an d ground water, and delivery via branching canals to water users. The linea r decision rule is an example of a rule that has been widely discussed in r eservoir operation Literature and is simple to program State variables, inc luding aquifer hydraulic head, streamflow, and surface water/aquifer interf low, are represented through discretized convolution integrals and influenc e coefficients. Reservoir storage and branching canal hows and interflows a re represented using embedded continuity equations. Results of model applic ation to a hypothetical study area under several scenarios indicate that th e more detail used to represent the physical system, the better the conjunc tive management. The most detailed representation provides 13% more water t han the least detailed system.