Economic Evaluation of Water Management Alternatives in the Upper Green River Basin of Wyoming

Abstract

Water use efficiency measures are generally recommended to reduce water use. Yet, flood irrigation practices in high-elevation mountain valleys of the Colorado River Basin headwaters generate return flows, which support late-season streamflow and groundwater recharge. Return flows support the ecosystem and provide recreational benefits. This study provides a framework for quantifying how land-use changes and associated return flow patterns affect the economic value of water across uses in a hydrologically connected, shallow alluvial aquifer system. This study first investigates how return flow patterns could change under three alternatives to flood irrigation: an increased use of center pivots, increased residential development, and conversion to pasture. The brown trout was used as an indicator species to track eco-hydrology, return flow, and capacity for recreational activities under each alternative. Estimates from the non-market valuation literature coupled with predicted changes in brown trout productivity approximate associated changes to recreational angler value. Recreational angler values are highest under the flood irrigation alternative. The inclusion of recreational angler values with agricultural values alters the magnitude of returns but not the rankings. These results highlight the potential heterogeneity of conclusions to be drawn regarding water use efficiency, depending on the economic value of water in different uses and the degree of hydrologic connectivity. This study also highlights data gaps and modeling needs for conducting similar future analyses.