{8c2c2741-2a96-4933-8e77-cf9613e7f33a} eng; USA utf8 dataset EnviroAtlas Coordinator U.S. Environmental Protection Agency, Office of Research and Development - Center for Public Health and Environmental Assessment (CPHEA), 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 2025-07-24 ISO 19115 Geographic Information - Metadata ISO 19115:2003/Cor.1:2006(E) EnviroAtlas - Stream Confluence Dataset - Map Data 2020-09-01 publication U.S. EPA Office of Research and Development (ORD) - Center for Public Health and Environmental Assessment (CPHEA) Research Triangle Park NC publisher U.S. Environmental Protection Agency (US EPA) originator This EnviroAtlas dataset is a point feature class showing the locations of stream confluences, with attributes showing indices of ecological integrity in the upstream catchments and watersheds of stream confluences and the results of a cluster analysis of these indices. Stream confluences are important components of fluvial networks. Hydraulic forces meeting at stream confluences often produce changes in streambed morphology and sediment distribution, and these changes often increase habitat heterogeneity relative to upstream and downstream locations. Increases in habitat heterogeneity at stream confluences have led some to identify them as biological hotspots. Despite their potential ecological importance, there are relatively few empirical studies documenting ecological patterns across the upstream-confluence-downstream gradient. To facilitate more studies of the ecological value and role of stream confluences in fluvial networks, we have produced a database of stream confluences and their associated watershed attributes for the conterminous United States. The database includes 1,085,629 stream confluences and 383 attributes for each confluence that are organized into 15 database tables for both tributary and mainstem upstream catchments ("local" watersheds) and watersheds. Themes represented by the database tables include hydrology (e.g., stream order), land cover and land cover change, geology (e.g., calcium content of underlying lithosphere), physical condition (e.g., precipitation), measures of ecological integrity, and stressors (e.g., impaired streams). We use measures of ecological integrity (Thornbrugh et al. 2018) from the StreamCat database (Hill et al. 2016) to classify stream confluences using disjoint clustering and validate the cluster results using decision tree analysis. 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). The purpose of this dataset is to provide EPA stakeholders an extensive database on environmental condition of stream confluences. Stream confluences are often biological hotspots and Clean Water Act (CWA) 305(b)/303(d) assessments are commonly based on stream biota. 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 - Center for Public Health and Environmental Assessment (CPHEA), 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 NOTPLANNED Ecosystem Environment Surface Water theme EPA GIS Keyword Thesaurus Ecosystem Services EnviroAtlas Environment Environmental Atlas Surface 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 vector eng; USA environment geoscientificInformation -125.00 -66.95 24.52 49.37 2015-11-19 EPA-Created and EPA-Value-added true Entity and Attribute Information Entity and Attribute Overview: Database contains landscape attributes at catchment and watershed scales for stream confluences defined from 2 or more inflowing streams. Landscape attributes are divided into 15 tables covering land cover and change, stressors, hydrology, physical condition, and ecological integrity. Additional details about this dataset are described in Ebert, D., Wickham, J., Neale, A., Mehaffey, M. 2020. A landscape assessment and associated dataset of stream confluences for the conterminous United States. Journal of the American Water Resources Association (JAWRA) 1 --13, https://doi.org/10.1111/1752-1688.12899. 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 - Center for Public Health and Environmental Assessment (CPHEA), 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/StreamConfluences_Sep2021_FGDB.zip download Download The URL providing direct access to the downloadable dataset. download https://enviroatlas.epa.gov/download/StreamConfluences_Sep2021_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://services.arcgis.com/cJ9YHowT8TU7DUyn/arcgis/rest/services/Stream_Confluences/FeatureServer 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/enviroatlas-data 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 are accurate to within 6-25 meters (EPA National Geospatial Data Policy [NGDP] Accuracy Tier 3). For more information, please see EPA's NGDP at http://epa.gov/geospatial/policies.html) Horizontal Positional Accuracy visual inspection meters 30 Vertical Positional Accuracy Report Vertical and horizontal accuracy are equivalent to that reported for NHDplus Version 2 Vertical Positional Accuracy Test performed by NHD and MRLC meters 25 Features represented have not been tested for completeness Features represented have not been tested for completeness Valid values = 1; This lineage was generated by the FGDC CSDGM to 19139 transformation Copied the National Hydrography Dataset (NHD) Plus v2.1 datasets for the lower 48 United States from the internal EnviroAtlas data repository. For original NHD Plus v2.1 documentation and metadata, see: www.horizon-systems.com/nhdplus/NHDPlusV2_documentation.php 2019-11-15T00:00:00 Projected all NHDPlus version2 NHDFlowlines, NHDAreas, and NHDWaterbodies to the USGS Albers standard projection used for the National Land Cover Database (NLCD) dataset. The XY Resolution and Tolerance parameter within the Geoprocessing Environment Settings was set to 0.000001 Meters for the reprojection. 2018-07-23T00:00:00 For each of the 18 2-digit NHD Hydrologic Unit (HUC) regions in the lower 48: 1)Selected the NHDFlowlines, NHDAreas, and NHDWaterbodies of interest (NHD flowlines were excluded if they did not have a catchment value attached to them; all coast flowlines and flowlines that occurred in lakes and ponds were also excluded. Flowlines that occurred in swamp areas were retained. Points where the remaining flowlines touched the coast were included in the dataset.); 2)Generated End Point vertices for the NHDFlowlines; 3) Selected the end points that either delimited an intersection between two or more flowlines, an intersection with a retained NHDWaterbody or NHDArea, or that intersected with a coastline. This is the NHD##_Confluence, where ## is the 2-digit NHD HUC region; 4) Deleted points from NHD##_Confluence layer that had the same XY coordinates. This is NHD##_Confluence_Pt; 5)Assigned the NHD##_Confluence_Pt ID to the NHD##_Confluence features that spatially overlapped; 6) Attributed the NHD##_Confluence_Pt layer with SRCount, SRTotArbol, and SRTotDASqk; 7) Assigned a BranchNum to each point in NHD##_Confluence; 8) Assigned CONFPT_ID values to NHD##_Confluence and NHD##_Confluence_Pt layers. 2019-03-20T00:00:00 Merged all 18 2-digit NHD HUC versions of NHD##_Confluence into NHD_CONUS_Confluence_v2; Merged all 18 2-digit NHD HUC versions of NHD##_Confluence_Pt into NHD_CONUS_Confluence_Pt_v2; Generated table, NHD_CONUS_COMID_v2, using a Pivot Table operation 2019-04-02T00:00:00 Associate attributes with points using data available through NHDplus V2 and StreamCat (https://www.epa.gov/national-aquatic-resource-surveys/streamcat) 2019-05-01T00:00:00 Organize attributes by theme into theme-specific tables 2019-06-01T00:00:00 Export ecological integrity indices attributes (ICI1, ICI2, ICI3, IWI1, IWI2, IWI3) as dbf and import into SAS. 2019-01-01T00:00:00 Use stream reach classification (1 = mainstem; 2=tributary) to classify ICI1, ICI2, or ICI3 as mainstem (ICIm) or tributary (ICIt) 2019-01-01T00:00:00 Classify IWI attributes and mainstem or tributary as described above of ICI 2019-01-01T00:00:00 Calculate contrast variables: ICWId1 = ICIm-IWIm. ICWId2 = ICIt-IWIt. ICId = ICIm-ICIt. IWId = IWIm-IWIt. 2019-01-01T00:00:00 Check Pearson correlations among ICIs, IWIs, and contrast variables. 2019-01-01T00:00:00 Initialization of disjoint cluster analysis (SAS FASTCLUS procedure) to provide seeds. Input variables - ICIm, IWIm, ICWId1, ICWId2, ICId, and IWId. Disjoint clustering based on medians, not means (SAS lease parameter set to 1). 2019-01-01T00:00:00 Repeat disjoint cluster analysis using seeds from previous steps for 10 to 30 clusters in steps of two (10, 12, …, 30). 2019-01-01T00:00:00 Select the cluster result (e.g., 10 clusters) that had the highest proportion of observations for which the distance between the observation and the centroid of its assigned cluster was less than or equal to 1/2 of the distance between the assigned cluster centroid and the nearest cluster centroid. Observations meeting this criterion are unambiguous members of the cluster to which they are assigned. The cluster result (e.g., 10 clusters) with the highest proportion was considered the most accurate classification. The result for 16 clusters had the highest proportion of observations meeting the criterion. 2019-01-01T00:00:00 Provide nominal labels for the final cluster result (16 clusters) The 16 clusters were given 4 nominal labels - good, moderate, poor, and contrast. Clusters were labeled "good" if ICIm and IWIm (see previous steps) were greater than or equal to 0.6. Clusters were labeled "poor" if ICIm and IWIm were less than or equal to 0.35. Clusters were labeled "moderate" when ICIm and IWIm were greater than or equal to 0.35 and less than 0.6. Clusters were labeled contrast when the absolute value of one or more of the contrast variables (ICWIm, ICWIt, ICId, and IWIt) was greater than or equal to 0.1 regardless of the values of ICIm and IWIm. 2019-01-01T00:00:00 Use the cluster assignment as input to a decision tree analysis (SAS hpsplit procedure). Difference between disjoint cluster analysis and decision tree is a measure of classification uncertainty. Entropy rule was used to grow tree; cost complexity was used to prune tree. 20% of observations were used as the model validation fraction. 2019-01-01T00:00:00 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 - Center for Public Health and Environmental Assessment (CPHEA), 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