Multicriterion Strategic Planning for Improved Irrigation Delivery. I: Approach

This paper develops an approach for assessing alternative strategies for improving an irrigation water delivery system in the context of multiple planning criteria. The methodology focuses on the exploration of distinct long-term, system-scale strategies to determine those which warrant further investigation in an implementation stage study. Alternatives that involve structural, managerial, and policy changes are discussed. A model is proposed for analyzing delivery system alternatives, using hydrologic simulation and incorporating water rights constraints. The model accounts for parameter uncertainty on both the supply and demand sides of the system resulting from temporal and spatial variability and inadequate data. Measures for the objectives of adequacy, efficiency, dependability, and equity of water delivery are used to evaluate system performance under each alternative considered. Expected values and coefficients of variation of these measures are considered over the planning horizon. Subjective notions attached to the evaluation of system performance are addressed by using fuzzy-set membership functions to interpret the expected values of performance measures. Techniques of multicriterion decision making are presented as a means of achieving an aggregate ranking of alternative strategies according to criteria such as water delivery performance, relative cost, social acceptability, political and institutional acceptability, and environmental impact. A companion paper applies the developed methodology to the Alamosa River and La Jara Creek systems in the San Luis Valley of south-central Colorado.