Assessed Use Attainment:
States and tribes adopt water quality standards that designate the uses of a waterbody and specify criteria to protect those uses. Typical uses of a water resource include drinking water supply, aquatic life use support, fish and shellfish consumption, primary and secondary contact recreation (e.g., swimming and boating), and agriculture. Biennially, states and tribes are required to report to EPA whether their water resources fully support, partially support, or fail to supporting their designated uses.
Fish and Wildlife Consumption Advisories:
Fish consumption advisories are a good indicator of the condition of a watershed because they are issued when the concentration of toxic substances in fish and shellfish exceed safe levels. Contamination of edible organisms indicates serious pollution problems in a waterbody, typically because persistent toxic chemicals have contaminated sediment or pathogens have contaminated the water column.
Source of Drinking Water:
The condition of watersheds effects their suitability as a source for drinking water. Water systems are regulated under the Safe Drinking Water Act, and EPA uses the Safe Drinking Water Information System (SDWIS) are used to identify situations where water systems have taken or may take actions because of actual or threatened source water problems. Such actions are a good indicator of poor or declining source water conditions.
Certain chemicals in water tend to bind to particles and collect in bottom sediments. When present at elevated levels in sediments, chemicals can kill or harm bottom dwelling organisms. Pollutants in sediments can also accumulate in aquatic organisms and move up the food chain to fish, shellfish and eventually humans.
Ambient Water Quality: Four Toxic Pollutants:
This indicator describes the degree to which monitoring of ambient concentrations of selected toxic pollutants (copper, nickel, zinc, and hexavalent chromium) show exceedances of national ambient water quality criteria. (Note that state water quality standards may differ from these EPA criteria.)
Ambient Water Quality: Four Conventional Pollutants:
This indicator describes the degree to which monitoring of ambient concentrations of selected conventional pollutants (ammonia, phosphorus, pH, and dissolved oxygen) show exceedances of national reference levels developed by EPA.
Wetlands Loss Index:
Wetlands make important contributions to the health of aquatic systems by purifying water, filtering runoff, abating floods, and decreasing erosion. In addition, wetlands provide habitat for countless numbers of plants and animals (including over 40% of all federally listed threatened or endangered species). Many wetland plants and animals support recreation and commercial industries. Recent measures of wetlands loss are combined with historic loss rates to form an index. The combined index is a more robust indicator of watershed condition than either loss rate used independently.