This project seeks to estimate the volumes of water that annually become available on forests (and other land covers) in the U.S. Available water volume (water supply) is being estimated, at the regional scale, as precipitation minus evapotranspiration (ET).
Estimating ET at the regional scale for the entire U.S. has been a major hurdle and is being accomplished in cooperation with scientists at Colorado State University. The publications listed below describe our efforts so far to estimate regional ET.
Mean annual contributions to water supply have been estimated for three sets of areas of the coterminous U.S.:
By national forests, and
By wilderness areas.
The other goal is to estimate the value of runoff from national forest areas (see Brown 2004). Work continues toward this goal.