Irrigation sagacity: a measure of prudent water use

Within the western United States, water rights are granted for reasonable a nd beneficial water use, and a measure of irrigation performance that embod ies this standard is needed. A new performance parameter, irrigation sagaci ty (IS), is recommended for this purpose. The term 'sagacity' comes from 's agacious', meaning wise or prudent. IS is more closely tied to the water ri ghts granted, and to the potential for water conservation and reallocation than is the traditional irrigation efficiency, which considers only benefic ial uses. Sagacious uses are either beneficial, or non-beneficial but reaso nable. Reasonable uses are those that, while not directly benefiting agrono mic production within the boundaries of the water rights area, are nonethel ess justified under prevailing conditions. Non-sagacious uses (non-benefici al and unreasonable) are those uses which are without economic, practical, or other justification. Determination of sagacity involves checking alterna te irrigation practices for practical, technical, economic, and environment al feasibility. Feasibility includes the requirement for a reasonable imple mentation schedule for any new practices. Only if a feasible alternate usin g less water is found should a current practice be considered in any part n on-sagacious. The results of a sagacity determination may vary depending on geographic scale, time frame, and perspective.