| OCR Text |
Show considered, and potential development of reservoir sites in addition to artificial recharge was considered as part of the planning exercise. Preliminary models developed, demonstrated that a much more effective strategy was to pursue a decomposition of the system in terms of groundwater and surface water, rather than by subregion. The subregional water rights constraints are then explicitly satisfied, and efficient algorithms for ground water and surface water management can be directly and parametrically exploited to develop measures for the response of the total water system, and to examine inherent trade- offs in water use and system reliability. Young and Bredehoeft ( 1972) present a linked simulation- optimization approach to conjunctive management. An institutional framework to minimize the impacts of aquifer pumping on river water rights was developed. Subarea operating models were formulated to solve for monthly surface and ground water use. These were solved sequentially with aquifer simulations during the growing season for a 10 year period. Issues related to regulation by a basin authority - taxation, development of new water supplies, and exchanges between ground and surface water supplies were considered. The focus was on agricultural use of water. Bredehoeft and Young ( 1983) extended this model to consider uncertain surface water supplies. Farmers were assumed to be risk averse. The stability of ground water supplies relative to surface water supplies, indicated extensive ground water development. The limitations of this work are ( a) single purpose use of waters and ( b) lack of consideration of water quality issues. The work was not directly pertinent to the objectives of this study. However, the use of linked simulation and optimization models for solving the conjunctive management problem appeared to be a very attractive proposition. It should be possible to model fairly complex situations efficiently using simulation, and functionally represent the results of the simulation model in an overall optimization scheme. This course of action was successfully explored in this study. Lumped parameter representations of the groundwater system are used by Coskunoglu and Shetty ( 1981), Flores et al ( 1978), Chaudhary et al ( 1974), Buras ( 1963, 1983), Buras and Hall ( 1961), Dracup ( 1966), Burt ( 1964) and Aron ( 1969). These were considered inadequate for the detail of representation of the water resource system, deemed necessary in this study. Simulation models are presented by Taylor and Luckey ( 1974) and Rushton and Tomlinson ( 1981). A fairly detailed representation of the hydrologic system is used with prescribed operation rules and digital simulation. The structure of the work is case specific, and its utility for comprehensive evaluation of resource utilization in terms of optimality or reliability criteria is limited. 10 |
