ABSTRACT
Because crop irrigation represents the largest single consumptive user of water in the United States and in the world, and many governments in arid areas have encouraged irrigated agriculture, measures of the economic impacts of changes in irrigated agriculture are of interest for evaluation of proposed irrigation-related public policies. Such policies include potential investments in new irrigation water supplies, transfers of irrigation water to emerging urban, industrial, and environmental demands, and plans for long-term groundwater management policies. Space limitations restrict this discussion to investment issues, although the concepts and evidence are relevant to related topics. This contribution identifies several types of economic impacts of irrigation development, sketches the conventional economic framework for evaluating public policies relating to irrigation, presents evidence on the magnitude of impacts, and concludes with a skeptical assessment of the social returns on public investments in irrigated agriculture and the methods used by public agencies to evaluate such investments.
