Whittlesey, Norman K.
This study presents a procedure for simultaneously addressing stochastic input demands and resource supplies for irrigated agriculture within a linear modeling framework. Specifically, the effect of stochastic crop net irrigation requirements and streamflow supplies on irrigation water management is examined. Irrigators pay a self-protection cost, in terms of water management decisions, to increase the probability that stochastic crop water demand is satisfied and anticipated water supply is available. Self-protection cost is lower when increasing the probability that anticipated water supplies are delivered, ceteris paribus, than when increasing the probability that the crop receives full net irrigation requirement in the study region.
Charging farmers increasing block prices for irrigation deliveries is advocated as a means of encouraging agricultural water conservation in the West. We formulated a model of a hypothetical irrigated river basin to investigate the hyrdro-economic circumstances in which such pricing leads to water conservation. Our results indicate that increasing delivery prices may encourage irrigators to make adjustments with countervailing impacts on consumptive water use and conservation. Whether these countervailing impacts combine to conserve water or increase its consumptive use must be resolved empirically. An alternative resolution of this ambiguity is to assess water prices in terms of consumptive use.
The value of maintaining a minimum streamflow objective on average is lessened when there is considerable dispersion around the average. An integrated economic and hydrology model is presented which provides water policy planners with a way to accurately measure both the economic cost and hydrologic consequences of maintaining a minimum streamflow level in an irrigated river basin at alternative probabilities of maintaining the target flow level. Water markets for streamflow augmentation are shown to be the most cost-effective policy in the study area.