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EPA Environmental Dataset Gateway
EPA Office of Water (OW): 303(d) Listed Impaired Waters NHDPlus Indexed Dataset
US Environmental Protection Agency, Office of Water
The 303(d) Listed Impaired Waters program system provides impaired water data and impaired water features reflecting river segments, lakes, and estuaries designated under Section 303(d) of the Clean Water Act. Each State will establish Total Maximum Daily Loads (TMDLs) for these waters. Note the CWA Section 303(d) list of impaired waters does not represent waters that are impaired but have an EPA-approved TMDL established, impaired waters for which other pollution control mechanisms are in place and expected to attain water quality standards, or waters impaired as a result of pollution and is not caused by a pollutant. Therefore, the "Impaired Waters" layers do not represent all impaired waters reported in a state's Integrated Report, but only the waters comprised of a state's approved 303(d) list. For more information regarding impaired waters refer to EPA's Integrated Reporting Guidance at:
. 303(d) waterbodies are coded onto NHDPlus v2.1 flowline and waterbody features to create line, area, and point events. In addition to NHDPlus reach indexed data there may also be custom event data (point, line, or polygon) that are not associated with NHDPlus and are in an EPA standard format that is compatible with EPA's Reach Address Database. These custom features are used to represent locations of 303(d) waterbodies that are not represented well in NHDPlus.
To identify the spatial extent of waters listed under 303(d). These waters can be linked to the 303(d) information stored in EPAs Assessment and TMDL Tracking and Implementation System (ATTAINS) for query and display via EPAs WATERS Expert Query Tool. The Source_FeatureID and Cycle_Year fields in the indexed dataset can be linked to the listed_water_id and cycle in EPA's Assessment and TMDL Tracking and Implementation System (ATTAINS).
Time Period of Content
West Bounding Longitude:
East Bounding Longitude:
North Bounding Latitude:
South Bounding Latitude:
impaired waters, 303d, TMDL, clean water act, National Hydrography Dataset, NHD, NHDPlus, listed waters, shapefile, total maximum daily loads, TMDLs, feature service, CWA, point source, GIS, EPA, Stream, reach
Although these data have been processed successfully on a computer system at the Environmental Protection Agency, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. It is strongly recommended that careful attention be paid to the contents of the metadata file associated with these data to evaluate data set limitations, restrictions or intended use. The U.S. Environmental Protection Agency shall not be held liable for improper or incorrect use of the data described and/or contained herein.
Metadata Reference Information
Metadata Standard Name:
FGDC Content Standards for Digital Geospatial Metadata
Metadata Standard Version:
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