The WEBB program began in 1991 at five small watersheds to examine water, energy, and biogeochemical fluxes and determine the effects of atmospheric deposition, climatic variables, and human influences on watershed processes. The five sites are at Loch Vale, Colorado; Luquillo Experimental Forest, Puerto Rico; Panola Mountain, Georgia; Sleepers River, Vermont; and Trout Lake, Wisconsin. These sites are supported, in part, by other programs in the USGS, other Federal and State Agencies, and Universities.