Document Type

Conference Paper

Journal/Book Title/Conference

Water in the 21st Century: Conservation, Demand, and Supply


American Water Resource Association

Publication Date


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Last Page



Concern for groundwater quality and availability is increasing in Pahvant Valley. Ground-water levels are declining due to intense groundwater extraction for irrigation; water having high total dissolved solids concentration is flowing from the southwest toward the pumping sites; and discharge from natural springs in a wildlife refuge is declining. Transient simulation of aquifer response to 20 years of the 1985 pumping rates (beginning with 1985 groundwater level) predicted that spring discharge would decrease by as much as 87% from 1985 rates. Presented are preliminary pumping strategies that maximize sustainable, steady-state groundwater extraction without unacceptably reducing discharge from the springs. A simulation/optimization (s/o) model is used to calculate optimized sustainable groundwater pumping rates that provide prespecified discharge rates from Clear Lake Springs. These optimal pumping strategies are sustainable unless significant changes occur in assumed system recharge and discharge rates. The usefulness of the s/o model for regional management is demonstrated by computing optimal strategies for four scenarios. Scenarios differ in the amount of discharge required from Clear Lake Springs or in the upper limit on pumping at individual locations. The optimal steady-state groundwater withdrawal and spring discharge rates obtained in this study are less than the 1985 rates. To provide sufficient sustainable discharge from Clear Lake Springs, pumping rates should be less than the 1985 rates.