BetaBetaDataset
To provide accessible geospatial information on impaired or threatened water bodies in the United States for water quality assessment, watershed management, environmental planning, and regulatory analysis.
The dataset from ArcGIS Living Atlas is based on EPA Clean Water Act Section 303(d) impaired waters reporting, where states, territories, and authorized tribes identify water bodies that do not meet water quality standards and require restoration planning through Total Maximum Daily Loads (TMDLs). The data are integrated into ArcGIS Living Atlas to support broader GIS and environmental analysis workflows
The dataset includes geospatial layers of impaired or threatened rivers, streams, lakes, and other water bodies, along with information on pollutants, causes of impairment, designated water uses, reporting dates, and TMDL-related attributes. Specialized layers also identify impairments associated with contaminants such as heavy metals and mercury
The data are collected through water quality monitoring and assessment programs conducted by state, tribal, and federal agencies under the Clean Water Act. Monitoring results are assessed against water quality standards, and impaired waters are reported through EPA systems such as ATTAINS and indexed to national hydrography datasets