U.S. Department of Agriculture, Natural Resources Conservation Service, National Geospatial Center of Excellence U.S. Geological Survey (USGS) 20250204 vector digital data U.S. Geological Survey, National Geospatial Technical Operations Center, P.O. Box 25046, Denver, CO 80225 U.S. Geological Survey, National Geospatial Technical Operations Centere https://ftpgeoinfo.msl.mt.gov/Data/Spatial/MSDI/HydrologicUnits Montana State Library 20250224 https://mslservices.mt.gov/Geographic_Information/Data/DataList/datalist_Details.aspx?did={327de47e-c0dd-4b93-94d2-9ea63b12ebca} The Watershed Boundary Dataset (WBD) is a comprehensive aggregated collection of hydrologic unit data consistent with the national criteria for delineation and resolution. It defines the areal extent of surface water drainage to a point except in coastal or lake front areas where there could be multiple outlets as stated by the "Federal Standards and Procedures for the National Watershed Boundary Dataset (WBD)" "Standard" (https://pubs.usgs.gov/tm/11/a3/). Watershed boundaries are determined solely upon science-based hydrologic principles, not favoring any administrative boundaries or special projects, nor particular program or agency. This dataset represents the hydrologic unit boundaries to the 12-digit (6th level) for the entire United States. Some areas may also include additional subdivisions representing the 14- and 16-digit hydrologic unit (HU). At a minimum, the HUs are delineated at 1:24,000-scale in the conterminous United States, meeting the National Map Accuracy Standards (NMAS). Higher resolution boundaries are being developed where partners and data exist and will be incorporated back into the WBD. WBD data are delivered as a dataset of polygons and corresponding lines that define the boundary of the polygon. WBD polygon attributes include hydrologic unit codes (HUC), size (in the form of acres and square kilometers), name, downstream hydrologic unit code, type of watershed, non-contributing areas, and flow modifications. The HUC describes where the unit is in the country and the level of the unit. WBD line attributes contain the highest level of hydrologic unit for each boundary, line source information and flow modifications. The data was previously updated through the USGS National Hydrography Dataset (NHD) Program approximately annually. Data are available as a geodatabase with all HUC levels or as shapefiles subset by HUC level (2-digit, 4-digit, 6-digit, 8-digit,10-digit, 12-digit). This dataset represents the Final Snapshot provided for download by the USGS on January 7, 2025. Find additional information on the USGS Watershed Boundary Dataset here: https://www.usgs.gov/national-hydrography/access-national-hydrography-products Future watershed boundary updates will be completed with the USGS 3D Hydrography Program (3DHP): https://www.usgs.gov/index.php/3DHP The intent of defining Hydrologic Units (HU) within the Watershed Boundary Dataset is to establish a base-line drainage boundary framework, accounting for all land and surface areas. Hydrologic units are intended to be used as a tool for water-resource management and planning activities particularly for site-specific and localized studies requiring a level of detail provided by large-scale map information. The WBD complements the National Hydrography Dataset (NHD) and supports numerous programmatic missions and activities including: watershed management, rehabilitation and enhancement, aquatic species conservation strategies, flood plain management and flood prevention, water-quality initiatives and programs, dam safety programs, fire assessment and management, resource inventory and assessment, water data analysis and water census. 20250204 Publication Date Complete As needed -117.835305 -101.435781 50.7131 43.696816 ISO 19115 Topic Categories inlandWaters boundaries sub-basin subbasin sub-watershed subwatershed hydrologic unit code hydrology Watershed Boundary Dataset HUC watershed boundaries HUC8 watershed WBD basin boundaries hydrologic unit subwatershed MSDI Montana Spatial Data Infrastructure None Montana Canada U.S. United States None 2025 None The distributor shall not be held liable for improper or incorrect use of this data, based on the description of appropriate/inappropriate uses described in this metadata document. It is strongly recommended that this data is directly acquired from the distributor and not indirectly through other sources which may have changed the data in some way. These data should not be used at scales greater than 1:24,000 for the purpose of identifying hydrographic watershed boundary feature locations in the U.S.A. The NRCS should be acknowledged as the data source in products derived from these data. The Watershed Boundary Dataset is public information and may be interpreted by all organizations, agencies, units of government, or others based on needs; however, they are responsible for the appropriate application of the data. Federal, State, or local regulatory bodies are not to reassign to the Natural Resources Conservation Service any authority for the decisions they make. The Natural Resources Conservation Service will not perform any evaluations of these maps or purposes related solely to State or local regulatory programs. Photographic or digital enlargement of these maps to scales greater than that at which they were originally delineated can result in misrepresentation of the data. If enlarged, the maps will not include the fine detail that would be appropriate for mapping at the small scale. Digital data files are periodically updated. Files are dated, and users are responsible for obtaining the latest version of the data from the source distributor. The Montana State Library Geographic Information Services provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time. U.S. Geological Survey, National Geospatial Technical Operations Center Authoritative Data Team mailing and physical

P.O. Box 25046

Denver Colorado 80225 US 1-888-ASK-USGS (1-888-275-8747) https://answers.usgs.gov/ 7:00 am - 3:30 pm, Central Time Prefer contact by e-mail. Montana State Library mailing

PO Box 201800

Helena MT 59620-1800 406-444-5354 Montana Relay 711 406-444-0266 geoinfo@mt.gov Funding and support for the Watershed Boundary Dataset (WBD) were provided by the Natural Resources Conservation Service, the Environmental Protection Agency, and the United States Geological Survey. Representatives from the U.S. Geological Survey and Environmental Protection Agency contributed a substantial amount of time and salary towards quality review and updating of the dataset in order to meet the Federal Standards for Delineation of Hydrologic Unit Boundaries. Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.1.3497 All attempts were made to verify 100% of the initially required attributes using 24K digital raster graphics (DRGs) as the base. Additional datasets, like the Geographic Names Information System (GNIS) and NHD, may also have been used to verify attribution. The accuracy of this data is dependent on the level of detail of the source material and the interpretation procedures for capturing that source. Other sources and methods may have been used to create or update WBD data. In some cases, additional information may be found in the WBD Metadata table. Lines, polygons and nodes conform to topological rules. Lines intersect only at nodes, and all nodes anchor the ends of lines. Lines do not overshoot or undershoot other lines where they are supposed to meet. There are no duplicate lines. Lines bound polygons. Gaps and overlaps among polygons do not exist. All polygons close. The WBD contains completed polygons at every level for the United States. All required fields within the polygon and line datasets are populated. Some of these fields may be populated with a zero "0". The lines coincident with the international boundary are assigned a HULevel value of 0. These cannot be attributed until the adjacent international units are added at which point the highest level of hydrologic unit can be determined. A detailed description of delineation methods and full attribute definitions can be found in the WBD Standards. Users are advised to carefully read the metadata record for additional details. The WBD was produced using a variety of digital spatial data including but not limited to Digital Raster Graphics (DRGs), aerial imagery and digital elevation models (DEMs). It is assumed these data are mapped at approximately 1:24,000-scale and contain a minimum inherent error of /- 40 feet. It should be noted that the WBD is undergoing continuous updates as source data improves and as hydrologic interpretations are refined. While general rules of hydrology were used in delineation, locations of boundaries may be subjective in some cases. Additional information may be found in the WBD Metadata table. A formal accuracy assessment of the vertical positional information in the data set has either not been conducted, or is not applicable. Vector GT-polygon composed of chains 115 NAD 1983 2011 StatePlane Montana FIPS 2500 45.0 49.0 -109.5 44.25 600000.0 0.0 coordinate pair 0.0001 0.0001 meter D NAD 1983 2011 GRS 1980 6378137.0 298.257222101 Montana State Library mailing

PO Box 201800

Helena MT 59620-1800 406-444-5354 Montana Relay 711 406-444-0266 geoinfo@mt.gov Downloadable Data See access and use constraints information. File Geodatabase https://prd-tnm.s3.amazonaws.com/StagedProducts/Hydrography/WBD/National/GDB/WBD_National_GDB.zip 20250204 U.S. Geological Survey, National Geospatial Technical Operations Center Authoritative Data Team mailing and physical

P.O. Box 25046

Denver Colorado 80225 US 1-888-ASK-USGS (1-888-275-8747) https://answers.usgs.gov/ 7:00 am - 3:30 pm, Central Time Prefer contact by e-mail. FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time The Montana State Library Geographic Information Services provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time. {0077A7D3-F6C3-4D08-9837-410E79A12FCC}