A logical step-by-step approach is needed to identify and abate nonpoint sources of pollution within Region 10. The first step must be to assess the magnitude and extent of the nonpoint source problem. Region 10 has developed a water quality assessment approach which will assist EPA planners, land agencies, and state and local agencies in identifying probable nonpoint sources and determining their effects upon the fishable- swimmable aspect of Regional streams. Generally the approach is to determine the biological, recreational, and water quality status of Regional streams and to display each status on color coded STORET basin maps. This information is to be related to land use and land ownership (also on basin maps) as well as other factors such as hydro- modifications, river flows, mining activities, and point source discharges. All this information is then systematically organized on a summary table which can be easily used.

"December 1976."