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Show Chapter 8 Summary This chapter presents a brief overview of the accomplishments of this study, and indicates some directions for further research. The review is classified into three categories - groundwater studies, surface water studies and conjunctive use studies. In each case the modeling advances as well as salient application results are reviewed. 8.1 Groundwater Models The objective of the groundwater management models developed was to analyze management objectives ( e. g. cost minimization, yield determination) in the context of jurisdictional ( water rights) and water quality maintenance constraints, in addition to the typically used constraints for drawdown control, demand satisfaction, and bounds on well pumping. The focus was metropolitan water use, rather than agrarian, and the primary concern was the development of well supplies for organized water supply agencies with jurisdictional conflicts at geographical boundaries. Small scale, individual ground water use was considered un- optimizable through regulation. A review of the literature, as well as initial investigations supported the belief that the unit response formulations were superior to the embedding formulations in terms of the ease and practicality of problem solution. The unit response formulation leads essentially to a decomposition of the simulation of aquifer response from its optimization. The degree of detail modeled is much more controllable in this case. Accordingly, a unit response formulation was posed for the management of stratified aquifers - a situation that does not readily lend itself to a unit response formulation. Models were also developed to determine optimal pumping schedules and spatial distribution with demand variability, water rights and water quality maintenance, and drawdown control. Response matrices of flows across boundaries of interest, to pumping at well nodes were developed to aid specification of constraints on water rights and water quality. Restoration of aquifer water quality, and the simulation of water quality parameters was not directly considered. The principles developed for water quality maintenance are however applicable for these objectives as well. The specification of regions of influence in space and time for each well was used to control the mathematical size of the problems formulated. A similar model to determine the optimal, steady state aquifer yield was also formulated. Parametric applications of these models were performed with data from Salt Lake County. A set of well nodes with good production characteristics was selected for optimization. Agency boundaries were identified over the aquifer, and constraints to maintain aquifer flow across these boundaries at prescribed levels were enforced. A similar treatment was accorded identifiable areas of contamination in the aquifer. The results suggest that there is a good potential for significantly and economically increasing the yield from the aquifer. Sandy and White City are areas of concern with respect to increases in groundwater development. A follow up study that focuses on these areas, with a finer discretization of the simulation grid in space and time is warranted. The applications described in chapter 3 did not consider the economics of water export/ import between agencies in the county, and of transfer within each agency. Since surface elevations vary considerably in the county, the parametric solutions in chapter 3 were considered to be of limiting utility. A set of applications was subsequently performed with water rights constraints between agencies not enforced, and the specification of the demand distribution at each candidate node modified to reflect variable lifts ( based on export from each well node to other well nodes) as a function of pumping at the node. As an example, if a well pumped at a rate in excess of the historical ' demand' at that node, the lift associated with 177 |