BBE4C3A6-1DE5-48F3-B043-4164830B35EB eng utf8 dataset 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 2025-08-11 ISO 19139 Geographic Information - Metadata - Implementation Specification 2007 geometryOnly composite 2644 32655 EPSG 9.8.8(3.0.1) EnviroAtlas - Hydrologic Sinks for the U.S. Pacific Territories 2025-06-11 creation 2025-06-11 publication U.S. Environmental Protection Agency (US EPA) originator U.S. EPA Office of Research and Development (ORD) - Center for Public Health and Environmental Assessment (CPHEA) Research Triangle Park, NC publisher 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 mapDigital This EnviroAtlas GIS dataset represents hydrologic sinks and major depressions in the landscape that are more than 2 meters deep, have a surface area of more than 78 square meters, and are fully on land. The dataset covers nine islands in the U.S. Pacific Territories of Guam, the Northern Mariana Islands, and American Samoa (the nine islands are Guam, Saipan, Tinian, Aguijan, Rota, Tutuila, Ofu, Olosega, and Ta'u) and was created using Digital Elevation Models from NOAA (2019-2022) as well as NOAA CCAP 1m landcover (2020-2021) and NCCOS (NOAA National Centers for Coastal and Ocean Science) shoreline files (2004-2005). 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 is useful for evaluating sites of aquifer recharge and prioritizing sink areas in the U.S. Pacific Territories for natural infrastructure interventions to increase water retention and green space and decrease pollution of groundwater. 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 publisher asNeeded American Samoa Guam Northern Mariana Islands United States Pacific Territories place EPA Place Names 2015-01-31 publication Ecosystem Environment Ground Water Surface Water Water theme EPA GIS Keyword Thesaurus 2007-11-02 publication 020:072 theme Federal Program Inventory 2013-09-16 publication Ecosystem Services EnviroAtlas Environment Environmental Atlas Green Infrastructure Land Cover theme User 2022-01-11 publication Map Files 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. EPA Public Domain License licenseUnrestricted https://edg.epa.gov/EPA_Data_License.html unclassified https://project-open-data.github.io/schema/#accessLevel N/A vector eng utf8 Microsoft Windows 10 Version 10.0 (Build 22631) ; Esri ArcGIS 13.3.0.52636 The Digital Elevation Models used in this dataset are from 2019-2022. true -180 180 -19.338041 15.284043 2019-01-01T00:00:00 2022-12-31T00:00:00 File Geodatabase Feature Class https://enviroatlas.epa.gov/download/HydrologicSinks_PacificTerritories_gdb.zip download download https://enviroatlas.epa.gov/download/HydrologicSinks_PacificTerritories_shp.zip download download https://enviroatlas-epa.hub.arcgis.com/search?tags=EA-HydrologicSinks ESRI:ArcGIS offlineAccess https://www.epa.gov/enviroatlas/enviroatlas-data information information https://www.epa.gov/enviroatlas information information dataset Tests for integrity have not been performed. 2025-06-11T00:00:00 EPA National Geospatial Data Policy Features have been reviewed by U.S. EPA EnviroAtlas Project Managers for public release. true Features represented have not been tested for completeness 2025-06-11T00:00:00 EPA National Geospatial Data Policy Features have been reviewed by U.S. EPA EnviroAtlas Project Managers for public release. true 2025-03-14 Following an internal review and comparison of multiple sink mapping outputs using various Digital Elevation Model (DEM) smoothing methods and resolutions (including visual comparison to published maps of sinks and input from WERI (the Water and Environmental Research Institute of the Western Pacific, at the University of Guam)), the project team decided to round DEM values to integers prior to running hydrologic tools. This helped remove minor surface noise and preserve the true shape and extent of sinks. 2025-03-18 Data Selection. DEM data resolution of approximately 3 meters was decided on. NOAA 3m DEMs for Guam, Saipan, Tinian, Aguijan, Rota (from NOAA Sea Level Rise Viewer). Data year: 2019-2020. Metadata: CNMI: coast.noaa.gov/slrdata/DEMs/MP/CNMI_dem_metadata_fy23.xml ; Guam:coast.noaa.gov/slrdata/DEMs/GU/Guam_dem_metadata_fy23.xml ; Spatial Reference: Guam: The DEM is referenced vertically to the Guam Vertical Datum of 2004 (GUVD04) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). CNMI: The DEM is referenced vertically to the Northern Marianas Vertical Datum of 2003 (NMVD03) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). NOAA NCEI 1/9 arc second DEM for American Samoa (Tutuila, Ofu, Olosega, and Ta’u). NOAA NCEI Continuously Updated Digital Elevation Model (CUDEM) - Ninth Arc-Second Resolution Bathymetric-Topographic Tiles: American Samoa files: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/dem/NCEI_ninth_Topobathy_AmSam_9460/index.html ; Data year: 2022. Spatial Reference: NAD 1983, Vertical datum: ASVD02 (vertical unit: meters). NOAA CCAP 1m landcover data (2020-2021) and NCCOS (NOAA National Centers for Coastal and Ocean Science) shoreline files (2004-2005) were used for each island. 2025-03-19 Reprojected Guam DEM to WGS 1984 UTM Zone 55N. Rounded DEM values to integers. Used Flow Direction and Sink tools in ArcGIS Pro 3.3.1 to map sinks. Created a depth raster by applying the Fill tool in ArcGIS Pro to the unrounded DEM, and then subtracting the original (unrounded) DEM from the filled DEM. Converted sinks to simplified polygons and assigned depth values using Zonal Statistics. Repeated these steps for Saipan, Tinian, Aguijan, Rota, Tutuila, and the Manu'a Islands. The CNMI DEM was reprojected to WGS 1984 UTM Zone 55N. The American Samoa DEMs were reprojected to WGS 1984 UTM Zone 2S. Vertical datums were not changed. 2025-03-24 Following literature review and communication with stakeholders, the team made the decision to exclude sinks with a depth of 2 meters or less or an area of 78 square meters or less, and any sink not fully on land (based on the NCCOS shoreline files). Completed sink filtering based on these parameters for all islands. 2025-03-28 Made the decision to symbolize sinks based on their dominant landcover (water, impervious, or neither water nor impervious). Calculated the percent area of each sink that is water and percent area that is impervious according to NOAA CCAP 1m landcover data. Created a field titled Sink_Dominant_Landcover and assigned values of "Water," "Impervious," and "Neither Water nor Impervious." 2025-04-28 Calculated the volume of each sink by multiplying the depth, width, and length of each cell, and then using Zonal Statistics to sum up the total volume of each sink. NOAA 3m DEM for Guam (from NOAA Sea Level Rise Viewer). Data year: 2019-2020. Metadata: Guam:coast.noaa.gov/slrdata/DEMs/GU/Guam_dem_metadata_fy23.xml ; Spatial Reference: The DEM is referenced vertically to the Guam Vertical Datum of 2004 (GUVD04) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). NOAA Office for Coastal Management Coastal Inundation Digital Elevation Model: Guam 2023-06-01 publication NOAA 3m DEM for Saipan, Tinian, Aguijan, Rota (from NOAA Sea Level Rise Viewer). Data year: 2019-2020. Metadata: CNMI: coast.noaa.gov/slrdata/DEMs/MP/CNMI_dem_metadata_fy23.xml ; Spatial Reference: The DEM is referenced vertically to the Northern Marianas Vertical Datum of 2003 (NMVD03) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). NOAA Office for Coastal Management Coastal Inundation Digital Elevation Model: CNMI 2023-06-01 publication NOAA NCEI 1/9 arc second DEM for American Samoa (Tutuila, Ofu, Olosega, and Ta’u). NOAA NCEI Continuously Updated Digital Elevation Model (CUDEM) - Ninth Arc-Second Resolution Bathymetric-Topographic Tiles: American Samoa files: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/dem/NCEI_ninth_Topobathy_AmSam_9460/index.html ; Data year: 2022. Spatial Reference: NAD 1983, Vertical datum: ASVD02 (vertical unit: meters). NOAA NCEI Continuously Updated Digital Elevation Model (CUDEM) - Ninth Arc-Second Resolution Bathymetric-Topographic Tiles: American Samoa 2022-02-07 publication NOAA CCAP 1m Landcover Phase 1 Initial Layers (water, impervious, and canopy only). NOAA CCAP 1m Landcover Phase 1 Initial Layers NCCOS (NOAA National Centers for Coastal and Ocean Science) shoreline files (2004-2005) NCCOS (NOAA National Centers for Coastal and Ocean Science) data for Guam, American Samoa, and CNMI. asNeeded