Water management and pricing in a conjunctive use system using supply -based pricing.

摘要

Water scarcity management through alternative rate structures in a conjunctive use system is examined. Using a model of a revenue-constrained conjunctive use irrigation district, irrigation water prices are developed that transmit the effects of water supply scarcity and encourage growers to respond to drought in ways current supply-independent pricing policies do not.;Water supply dependent prices are developed theoretically and estimated empirically using data from the Arvin-Edison Water Storage District. To achieve optimal water use it is necessary to price both ground and surface water. Water subsidies, particularly on groundwater during periods of extreme drought, are necessary under some supply conditions and management policies. Conjunctive use introduces discontinuities into surface water prices and volumetric charges on groundwater and shifts the revenue base of the District to whichever water source is being made less-scarce by District operations.;Evaluation of rate changes through simulation and ex post empirical analysis suggest growers respond to water scarcity and rate changes primarily through acreage adjustments. Simulations show supply-based water pricing leads to a temporal reallocation of acreage away from drought periods and to increased production when water costs are lowest. Within a drought period, fallowing increases and cultivated acreage shifts to less water intensive and more profitable crops, suggesting that growers' profits are potentially higher under supply-based pricing. These results confirm previous research suggesting that growers respond to drought primarily through a combination of crop selection and acreage fallowing. Empirical results confirm this result only partially and indicate growers' acreage allocation and water consumption may be subject to significant hysteresis.