USGS Water Quality Data
The USGS collects and maintains water quality information from thousands of sites across the United States.
National Rivers and Streams Assessment (NRSA)
The NRSA is an EPA-led survey of water quality and ecological health of the nation’s streams and rivers (completed in 2008).
Wadeable Streams Assessment (WSA)
The WSA is a survey of ecological conditions of small streams throughout the Unites States (completed in 2005).
Woody riparian vegetation near selected stream gages in the Western United States
Areal cover and occupancy of woody riparian species near 456 stream gages in the western United States were obtained from site visits during the growing seasons of 1996–2002.
State bioassessment data
Most states conduct their own ecological surveys and collect bioassessment data. Check with states agencies for data availability.