Appropriated Surface Water Metric
This source attempts to quantify water that could be made available for new development by abandonment and transfer of the water right from its prior use. Such transfers have traditionally involved sales of water rights off irrigated farm land to urban uses. The potential for such transfers is estimated based on the irrigated acreage in a given watershed that is devoted to low value agricultural production; specifically, irrigated hay and alfalfa. Data (irrigated acreage and water volume applied) are taken from the U.S. Department of Agriculture’s Agricultural Census (USDA 2007). There is often resistance to large areas of agriculture being abandoned. As such land abandonment is limited to 5% of the total irrigated acreage in the watershed. This limit is based on the average projected decline in irrigation across the western U.S.
For watersheds experiencing significant groundwater depletions (see unappropriated groundwater metric above) the available appropriated water is reduced by 50%. This is to account for the fact that some portion of future water rights abandonment is likely to be used to offset the groundwater depletion.
Appropriated Surface Water Cost
Water rights transfer costs are based on historic data collected by the Water Strategist and its predecessor the Water Intelligence Monthly (Water Strategist 2012). Costs are estimated by state because of the limited availability of data. Only transactions involving permanent transfers are used. Recorded transfers are averaged by year and by state and the average of the last 5 years used for purposes of this study. No efforts are made to project how costs may vary in time given the wide range of factors and associated uncertainty that plays into the water transfers market.
U.S. Department of Agriculture, 2007. The Census of Agriculture, available at: http://www.agcensus.usda.gov/
To view the sources and processes used to calculate estimates for all metrics, select a state below: