{cf3132f1-4d70-4316-9cf2-07ffec3e4112} 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 - Percentage of stream and water body shoreline lengths within 30 meters of >= 5% or >= 15% impervious cover by 12-Digit HUC for the Conterminous United States 2016-06-13 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 shows the percentages of stream and water body shoreline lengths within 30 meters of impervious cover by 12-digit Hydrologic Unit (HUC) subwatershed in the contiguous U.S. Impervious cover alters the hydrologic behavior of streams and water bodies, promoting increased storm water runoff and lower stream flow during periods in between rainfall events. Impervious cover also promotes increased pollutant loads in receiving waters and degraded streamside habitat. This dataset shows were impervious cover occurs close to streams and water bodies, where it is likely to have a greater adverse impact on receiving waters. This dataset was produced by the US EPA to support research and online mapping activities related to the 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). The map, impervious cover near streams and water bodies, provides baseline information on the total length of aquatic resource shorelines that are adjacent to impervious cover. The map can be used to compare watersheds across a region according to the amount of stream and shoreline length in the vicinity of impervious cover. This indicator can also be used in conjunction with its "cousin," percentage impervious cover area in the watershed, to determine the spatial pattern of impervious cover. Suppose that impervious cover near streams and water body shorelines was 10% and the percentage of impervious cover in the watershed was only 5%. The relative difference between the two indicators suggests that impervious cover for that watershed tended to be located in the vicinity of streams and water body shorelines. We refer to this as proximally distributed impervious cover. Impervious cover is now being used as a watershed planning and management indicator. The spatial pattern of impervious cover is likely to also be useful for watershed planning and management because it can be used to determine if a watershed has proximally distributed (tends to occur near streams), distally distributed (tends to occur far from streams) or uniformly distributed (evenly spread throughout the watershed) impervious cover. In a nationwide (continental only) assessment, we found that 27% of the watersheds had proximally distributed impervious cover. The overall goal of the 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 Ecosystem Services EnviroAtlas Environment Environmental Atlas Land Cover Potential for Change - Ecosystem Services Riparian Surface Water Water Wetlands 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 9999-01-01 true Entity and Attribute Information Entity and Attribute Overview: In general, three data sets were used to estimate percentage of stream and water body shoreline lengths within 30 meters of impervious cover. Impervious cover (IC) from National Land Cover Database (NLCD) from the Multi-Resolution Land Characteristics Consortium (MRLC) (2011); version 2 of the NHD 1:100,000-scale hydrography data (downloaded between October, 2014 and January, 2015); and 12-digit Hydrologic Unit (HUCs) from the Watershed Boundary Dataset (WBD), (2015). The IC data were aggregated to five classes, and GIS functions were used that "grew" IC by one pixel into 0% IC pixels only. The expanded IC map was then used in a tabular intersection to determine the percentage of stream and water body shoreline lengths in the vicinity (within 30 meters) of IC. The results were summarized by 12-digit Hydrologic Unit (HUCs) from the Watershed Boundary Dataset. The indicators in the dataset are the percentage of stream and water body shoreline lengths in the vicinity >= 5% and >= 15% IC. The estimates for >= 5% IC are from the summation of the results for the 5% - 14%, 15% - 24%, and > 25% aggregated IC classes, and the estimates for the >= 15% IC are from the summation of the results for the 15% - 24% and > 25% aggregated IC classes (see above for description of IC aggregated classes). Wickham JD, Wade TG, Norton DJ. 2014. Spatial patterns of watershed impervious cover relative to stream location. Ecological Indicators 40:109-116. Wickham JD, Neale AC, Mehaffey MH, Jarnagin T, Norton DJ. In press. Temporal trends in the spatial distribution of impervious cover relative to stream location. J. Am. Water. Resources. Assoc. 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. Using ArcGIS 10.2(1), re-classed impervious cover (IC) from the National Land Cover Database (NLCD) 2011 Percent Developed Impervious dataset into: 0%; 1% - 4%; 5% - 14%; 15% - 24%; > 25%. 2015-04-27T00:00:00 2. Split the re-classed IC map into class-specific maps, producing separate maps for IC of 1% - 4%, 5% - 14%, 15% - 24%; > 25%. Values for pixels outside the class-specific ranges were set to zero (0), and values within the class-specific range were set to the minimum value of the range. 2015-04-27T00:00:00 3. "Grew" the re-classed, class-specific IC maps by 1 pixel using the ArcGIS expand function. 9999-01-01T00:00:00 4. Combined the expanded, re-classed, class-specific IC maps with the original NLCD IC re-classed map produced in step 1, using the ArcGIS Combine tool. 9999-01-01T00:00:00 5. Re-classed the combined map produced in step 4 so that IC "grew" into pixels that were 0% IC only in the map produced in step 1. For a given pixel, suppose the combined map produced in step 4 had values of 0, 1, 0, 0, 0. For that pixel, IC was 0% in the original map, within 30 meters of 1% - 4% IC, but not within 30 meters of the other IC classes. This pixel would be classified as 1 in the step 5 output based on the coding scheme described in step 2. Suppose another pixel from the step 4 output had values of 0, 1, 5, 15, 25. This pixel, which is 0% in the original NLCD IC map, has immediate neighbors in all 4 of the IC aggregated classes (i.e., map produced in step 1). We used a maximum rule for re-classification when more than one of the four aggregated IC classes occurred in the immediate vicinity of a 0% IC pixel. So a pixel with values of 0, 1, 5, 15, 25 in the map produced in step 4 would be re-classified as 25. 9999-01-01T00:00:00 6. The map produced in step 5 was used in the ArcGIS tabulate areas function with version 2 of NHDPlus 1:100,000-scale streams and water bodies to determine the proportion (percentage) of stream and water body shoreline lengths that had IC within 30 meters. NHDplus hydrography codes for streams (both area and line features) were 33400 (connector), 46000 (stream) 46003 (intermittent stream), and 46006 (perennial stream). NHDplus hydrography codes for water bodies were 39001 (intermittent lake/pond), 39004 (perennial lake/pond), 39005 (intermittent lake/pond; stage = high water elevation), 39006 (intermittent lake/pond; stage = date of photography), 39009 (perennial lake/pond; stage = average water elevation), 39010 (perennial lake/pond; stage = normal pool), 43600 (reservoir), and 43601 (reservoir; reservoir type = aquaculture). 2015-04-27T00:00:00 7. The results from tabulate areas were used to produce two indicators: percentage of stream and water body shoreline lengths that had IC >= 5% within 30 meters, and percentage of stream and water body shoreline lengths that had IC >= 15% within 30 meters. Percentage of stream and water body shoreline lengths that had IC >= 5% within 30 meters is based on the summation of results for the three aggregated classes (step 1) 5% - 15%, 15% - 24%, and > 25%, and the indicator percentage of stream and water body shoreline lengths that had IC >= 15% within 30 meters is based on the summation of results for the two aggregated classes (step 1) 15% - 24% and > 25%. Two additional metrics, StrL and LakL, provide the total stream and shoreline length (in meters) for each watershed. They can be used with the percentage metrics to calculate the total length of streams and shorelines in the vicinity of >= 5% or >= 15% impervious cover. 2015-04-27T00:00:00 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