Modeling of Water Quality Benefits

For its Clean Water Act programs, the U.S. Environmental Protection Agency (EPA) has historically focused on use/recreation values of freshwater rivers and lakes, with limited ability to value non-use in a systematic way. Recently, three offices within EPA have worked together to develop a water quality benefits modeling framework to support improved quantification of the economic benefits of aquatic environmental changes nationwide. The approach combines water quality data or modeling output into a water quality index, which is then combined with a valuation model and spatial distribution and demographic data to estimate total benefits. The modeling platform replaces ad hoc approaches, and expands benefits coverage to the national scale. We present an example application for lakes.