{F6AE1B0B-9C59-463C-9D80-BAE4AA460CEE} eng; USA utf8 dataset EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact 2025-07-23 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) EnviroAtlas - 303(d) Impairments by 12-digit HUC for the Conterminous United States 2016-04-27 publication U.S. EPA Office of Research & Development (ORD) - National Exposure Research Laboratory (NERL) Research Triangle Park NC publisher US Environmental Protection Agency (US EPA) originator This EnviroAtlas dataset depicts the total length of stream or river flowlines that have impairments submitted to the EPA by states under section 303(d) of the Clean Water Act. It also contains the total lengths of streams, rivers, and canals, total waterbody area, and stream density (stream length per area) from the US Geological Survey's high-resolution National Hydrography Dataset (NHD). This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheet (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets). This dataset shows the lengths of streams with and without impairments, the density of total streams, and the area of waterbodies by HUC12. Users can use this data to assess the type and extent of impairments in their watersheds. This information could be used to target watersheds in need of Best Management Practices (BMPs) to reduce non-point source pollution, or to develop remediation strategies that address common sources of impairments in a watershed. Stream length, density, and area could be used to study water supply. Users can also view this information along with other layers. For example, layers from this dataset could be overlaid with layers on impervious surface or riparian buffers, to identify possible sources of impairments and remediation needs, or combined with recreation layers to see where impairments could impact recreational use of waters. The overall goal of EnviroAtlas is to employ and develop the best available science to map indicators of ecosystem services production, demand, and drivers for the nation. completed EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact asNeeded Ecosystem Environment theme EPA GIS Keyword Thesaurus 12-digit HUCs Biota Contaminant Drinking Water Ecosystem Services EnviroAtlas Environment Environmental Atlas Regulatory Surface Water Toxics Water theme EnviroAtlas Alabama Arizona Arkansas California Colorado Connecticut Delaware Florida Georgia Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota Tennessee Texas United States Utah Vermont Virginia Washington Washington DC West Virginia Wisconsin Wyoming place None https://edg.epa.gov/EPA_Data_License.html otherRestrictions Use Constraints: None. Please check sources, scale, accuracy, currency and other available information. Please confirm that you are using the most recent copy of both data and metadata. Acknowledgement of the EPA would be appreciated. otherRestrictions Access Constraints: None PUBLIC https://project-open-data.github.io/schema/#accessLevel Standard Technical Controls eng; USA environment -128.02839229 -65.20336449 22.7348894 51.6773602 2015-05-01 2016-04-01 Due to differences in how streams were recorded in the maps used to develop the NHD, stream length and stream density vary in some regions due to overcounting or undercounting of streams. Stream length and density should be taken as approximations. While most features in the 303(d) impairments list are coded onto NHD features, there are some custom data that are not associated with NHD; the NHD and 303(d) datasets do not always align. Therefore, in some 12-digit HUCs, the length of 303(d) impaired segments may exceed the length of segments recorded in the NHD dataset. In addition, the data on impairments only represent waters on a state's approved 303(d) list, and not all impaired water bodies. The extent of monitoring and the methods used vary from state to state. The 303(d) list does not include impaired waters with an established TMDL (Total Maximum Daily Load), impaired waters for which other pollution control mechanisms are in place and expected to attain water quality standards, or waters with impairments that are not result of pollution. Additionally, the data are for whatever year each state last submitted its list of impaired waters to the EPA; these data are not all from the same year. Finally, the same stream segment may have multiple impairments. Therefore, summing the stream lengths for all impairments in a HUC may result in a number that is greater than the value for TotImpLen. true Entity and Attribute Information Entity and Attribute Overview: For more information about EnviroAtlas data, go to https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets. Stream length is based on the high-resolution NHD flowlines. The feature types STREAM/RIVER, CANAL/DITCH, and CONNECTOR were included; ARTIFICIAL PATH was included only where the path has a corresponding NHDArea feature with FTYPE StreamRiver. The feature types COASTLINE, PIPELINE, and UNDERGROUND CONDUIT were excluded. Waterbody area is based on the high-resolution NHD waterbodies. All waterbody feature types were included. The impairment parent causes were grouped into the following categories: * Temperature: TEMPERATURE; * Sediment and Turbidity: SEDIMENT, TURBIDITY; * Biota: CAUSE UNKNOWN - FISH KILLS, CAUSE UNKNOWN - IMPAIRED BIOTA, FISH CONSUMPTION ADVISORY; * Mercury: MERCURY; * Metals other than mercury: METALS (OTHER THAN MERCURY); * Nuisance species: ALGAL GROWTH, NOXIOUS AQUATIC PLANTS, NUISANCE EXOTIC SPECIES, NUISANCE NATIVE SPECIES; * Nutrients: NUTRIENTS; * OrganicEnrichO2Deplet: ORGANIC ENRICHMENT/OXYGEN DEPLETION; * Pathogens: PATHOGENS; * Pesticides: PESTICIDES; * pH: PH/ACIDITY/CAUSTIC CONDITIONS; * Other: CAUSE UNKNOWN, OTHER CAUSE, FLOW ALTERATION(S), HABITAT ALTERATIONS, AMMONIA, BIOTOXINS, CHLORINE, DIOXINS, OIL AND GREASE, POLYCHLORINATED BIPHENYLS (PCBS), RADIATION, SALINITY/TOTAL DISSOLVED SOLIDS/CHLORIDES/SULFATES, TASTE, COLOR, AND ODOR, TOTAL TOXICS, TOXIC INORGANICS, TOXIC ORGANICS, TRASH * Total impairments: All causes No feature types were removed from the impaired waters database; a small fraction of the impairments are for coastlines or pipelines. For more information about EnviroAtlas data, go to https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets." Entity and Attribute Detail Citation: https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas distributor https://enviroatlas.epa.gov/download/CONUS_metrics_FGDB.zip download Download The URL providing direct access to the downloadable dataset. download https://enviroatlas.epa.gov/download/CONUS_metrics_CSV.zip ESRI:ArcGIS API The endpoint of a web service to access the dataset (REST endpoint, WMS GetCapabilities URL, or a SOAP WSDL endpoint). webMapService https://www.epa.gov/enviroatlas/enviroatlas-data information Documentation URL for accessing related documents such as data dictionary, technical information about a dataset, developer documentation, etc. information https://www.epa.gov/enviroatlas information Home Page Alternative landing page used to redirect user to a contextual, Agency-hosted "homepage" for the Dataset or API information dataset Horizontal Positional Accuracy Report Data were collected using methods that have unknown accuracy (EPA National Geospatial Data Policy [NGDP] Accuracy Tier 10). For more information, please see EPA's NGDP at https://epa.gov/geospatial/policies.html Features represented have not been tested for completeness Features represented have not been tested for completeness Tests for integrity have not been performed. This lineage was generated by the FGDC CSDGM to 19139 transformation 1. Calculate the length of impaired waters by cause. 2016-04-18T00:00:00 1.a. Obtained May 1, 2015 303(d) Listed Impaired Waters NHD Indexed Dataset from https://www.epa.gov/waterdata/waters-geospatial-data-downloads#303dListedImpairedWaters. 2016-04-18T00:00:00 1.b. Dissolve rad_303d_l (Reach Address Database - feature class showing impaired reaches from the 303(d) Listed Impaired Waters NHD Indexed Dataset) on ESRI_key (convenience key provided to aid in joins and relates in ESRI software). 2016-04-20T00:00:00 1.c. Identify impaired stream reaches for each category of impairment causes; the categories consist of groups of parent causes from attgeo_303dcaussrce (table of 303(d) Listed Impaired Waters by Causes of Impairment and Probable Sources from 303(d) Listed Impaired Waters NHD Indexed Dataset). See the overview section of the metadata for details on categories used. 2016-04-20T00:00:00 1.d. Relate attgeo_303dcaussrce to rad_303d_l using the field ESRI_key. 2016-04-20T00:00:00 1.e. Select reaches with impairment causes included in each EnviroAtlas impairment category. Select from attgeo_303dcaussrce where LW_PARENT_CAUSE_NAME (cause of impairment group name such as 'Pathogens' or 'Sediment') = "CAUSE" and select Related Tables to select all reaches with a given impairment cause. Export selected features, and dissolve them to prevent double-counting of streams with more than one impairment. 2016-04-20T00:00:00 1.d. For each category of impairment causes, find the total length of impaired streams in each HUC12. Intersect each dissolved feature class from the previous step with the NHDPlusV2_WBDSnapshot_EnviroAtlas_CONUS. Add the field "KM", calculate the length in kilometers, then summarize on the HUC_12 field, with the sum of "KM" as a summary statistic. The output will be a table for each impairment category containing the total length of all impaired streams by HUC12. 2016-04-21T00:00:00 2. Calculate the total waterbody area, total stream length, and stream density by HUC12. 2016-04-25T00:00:00 2.a. Obtain the high-resolution NHD datasets, by state, from the USGS (ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/Hydrography/NHD/State/HighResolution). 2016-04-25T00:00:00 2.b. Merge NHDWaterbody shapefiles for all states, then use the Delete Identical tool to eliminate duplicated lines that were created by the merge. Repeat with NHDFlowline and NHDArea shapefiles. 2016-04-25T00:00:00 2.c. Find the total area of all waterbodies in each HUC12. Dissolved the merged waterbodies feature class. Intersected it with NHDPlusV2_WBDSnapshot_EnviroAtlas_CONUS. Calculated the area in square kilometers for each feature in the intersection. Summarized on the HUC_12 field, with the sum of square kilometers as a summary statistic. Change any nulls to zero. The output is a table with the total waterbody area for each HUC12. 2016-04-26T00:00:00 2.d. Find the total stream length for each HUC12. First, remove flowlines that do not represent streams or rivers. Add a field for feature type (FTYPE) names to the merged NHD flowlines; use the table from the help file at http://nhd.usgs.gov/userGuide/Robohelpfiles/NHD_User_Guide/Feature_Catalog/Hydrography_Dataset/Complete_FCode_List.htm to add feature types based on FCODE. Do the same for the merged NHDArea feature class. Add a second field to the flowlines, AreaFCODE. Join the merged NHDArea feature class to the flowlines using the Permanent_Identifier from NHDArea and WBArea_Permanent_Identifier from NHDFlowlines. Copy the FCODE from NHDArea to AreaFCODE in the flowlines. Delete all flowlines with feature type 'COASTLINE,' 'PIPELINE,' or 'UNDERGROUND CONDUIT;' also delete ARTIFICIAL PATH features if AreaFCODE does not equal 'STREAM/RIVER.' The remaining reaches are of FTYPE STREAM/RIVER, CANAL/DITCH, CONNECTOR, or ARTIFICIAL PATH, where ARTIFICIAL PATH represents STREAM/RIVER areas. Intersect the remaining flowlines with the 12-digit HUCs, then dissolve the output on the HUC_12 field. Calculate length in kilometers. 2016-04-27T00:00:00 2.e. Calculate stream density. Calculate the areas of the 12-digit HUCs in square kilometers, join them to the flowlines, and divide stream length by HUC12 area to find stream density. 2016-04-29T00:00:00 3. Get the total length of streams with any 303(d) impairment. Intersect rad_303d_l with the 12-digit HUCs, dissolve the output on HUC_12, and calculate the flowline length in kilometers for each HUC12. 2016-04-29T00:00:00 4. Join outputs and export to Impaired_Waters_2016. 2016-04-29T00:00:00 unknown 2029-07-23 This metadata was automatically generated from the FGDC Content Standard for Digital Geospatial Metadata standard (version FGDC-STD-001-1998) using the 2024-02-09T11:11:00 version of the FGDC CSDGM to ISO 19139 transform. EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development-Sustainable and Healthy Communities Research Program, EnviroAtlas Geospatial Data Owner (919) 541-3832 109 T.W. Alexander Drive Research Triangle Park NC 27709 EnviroAtlas@epa.gov https://www.epa.gov/enviroatlas pointOfContact