The High Resolution National Hydrography Dataset Plus (NHDPlus HR) is an integrated datset of geospatial data layers, including the most current National Hydrography Dataset (NHD), the 10-meter 3D Elevation Program Digital Elevation Model (3DEP DEM), and the National Watershed Boundary Dataset (WBD). The NHDPlus HR combines the NHD, 3DEP DEMs, and WBD to create a stream network with linear referencing, feature naming, "value added attributes" (VAAs), elevation-derived catchments, and other features for hydrologic data analysis. The stream network with linear referencing is a system of data relationships applied to hydrographic systems so that one stream reach "flows" into another and "events" can be tied to and traced along the network. The VAAs provide capabilities for upstream and downstream navigation with linear referencing, analysis, and modeling. The elevation derived catchments are used to associate other landscape attributes, such as land cover, with stream ...

The National Hydrography Dataset (NHD) is a feature-based database that interconnects and uniquely identifies the stream segments or reaches that make up the nation's surface water drainage system. NHD data was originally developed at 1:100,000-scale and exists at that scale for the whole country. This high-resolution NHD, generally developed at 1:24,000/1:12,000 scale, adds detail to the original 1:100,000-scale NHD. (Data for Alaska, Puerto Rico and the Virgin Islands was developed at high-resolution, not 1:100,000 scale.) Local resolution NHD is being developed where partners and data exist. The NHD contains reach codes for networked features, flow direction, names, and centerline representations for areal water bodies. Reaches are also defined on waterbodies and the approximate shorelines of the Great Lakes, the Atlantic and Pacific Oceans and the Gulf of Mexico. The NHD also incorporates the National Spatial Data Infrastructure framework criteria established by the Federal Geographic Data Committee. For additional information on NHD, go to https://www.usgs.gov/national-hydrography.

The National Hydrography Dataset (NHD) is a comprehensive set of digital spatial data that encodes information about naturally occurring and constructed bodies of surface water (lakes, ponds, and reservoirs), paths through which water flows (canals, ditches, streams, and rivers), and related entities such as point features (springs, wells, stream gages, and dams). The information encoded about these features includes classification and other characteristics, delineation, geographic name, position and related measures, a "reach code" through which other information can be related to the NHD, and the direction of water flow. The network of reach codes delineating water and transported material flow allows users to trace movement in upstream and downstream directions. In addition to this geographic information, the dataset contains metadata that supports the exchange of future updates and improvements to the data. The NHD is available nationwide in two seamless datasets, one based on 1:24,000-scale maps and referred to as high resolution NHD, and the other based on 1:100,000-scale maps and referred to as medium resolution NHD. Additional selected areas in the United States are available based on larger scales, such as 1:5,000-scale or greater, and referred to as local resolution NHD. The NHD supports many applications, such as making maps, geocoding observations, flow modeling, data maintenance and stewardship. For additional information, go to https://nhd.usgs.gov.

The USGS National Hydrography Dataset (NHD) downloadable data collection from The National Map (TNM) is a comprehensive set of digital spatial data that encodes information about naturally occurring and constructed bodies of surface water (lakes, ponds, and reservoirs), paths through which water flows (canals, ditches, streams, and rivers), and related entities such as point features (springs, wells, stream gages, and dams). The information encoded about these features includes classification and other characteristics, delineation, geographic name, position and related measures, a "reach code" through which other information can be related to the NHD, and the direction of water flow. The network of reach codes delineating water and transported material flow allows users to trace movement in upstream and downstream directions. In addition to this geographic information, the dataset contains metadata that supports the exchange of future updates and improvements to the data. The NHD supports many applications, such as making maps, geocoding observations, flow modeling, data maintenance, and stewardship. For additional information on NHD, go to https://www.usgs.gov/core-science-systems/ngp/national-hydrography.

DWR was the steward for NHD and Watershed Boundary Dataset (WBD) in California. We worked with other organizations to edit and improve NHD and WBD, using the business rules for California. California's NHD improvements were sent to USGS for incorporation into the national database. The most up-to-date products are accessible from the USGS website. Please note that the California portion of the National Hydrography Dataset is appropriate for use at the 1:24,000 scale.

For additional derivative products and resources, including the major features in geopackage format, please go to this page: https://data.cnra.ca.gov/dataset/nhd-major-features Archives of previous statewide extracts of the NHD going back to 2018 may be found at https://data.cnra.ca.gov/dataset/nhd-archive.

In September 2022, USGS officially notified DWR that the NHD would become static as USGS resources will be devoted to the transition to the new 3D Hydrography Program (3DHP). 3DHP will consist of LiDAR-derived hydrography at a higher resolution than NHD. Upon completion, 3DHP data will be easier to maintain, based on a modern data model and architecture, and better meet the requirements of users that were documented in the Hydrography Requirements and Benefits Study (2016). The initial releases of 3DHP include NHD data cross-walked into the 3DHP data model. It will take several years for the 3DHP to be built out for California. Please refer to the resources on this page for more information.

The FINAL,STATIC version of the National Hydrography Dataset for California was published for download by USGS on December 27, 2023. This dataset can no longer be edited by the state stewards. The next generation of national hydrography data is the USGS 3D Hydrography Program (3DHP).

Questions about the California stewardship of these datasets may be directed to nhd_stewardship@water.ca.gov.

This service is a cached overlay of a cartographic representation of the National Hydrography Dataset (NHD). ​The NHD is a comprehensive set of digital ​geo​spatial data that encodes information about naturally occurring and constructed bodies of surface water​, paths through which water flows​, ​related features​ such as stream gages and dams​​, and additional hydrologic information​. ​It is available nationwide ​in a 1:24,000-scale seamless dataset, referred to as high resolution NHD. The NHD supports many applications, such as making maps, geocoding observations, flow modeling, data maintenance and stewardship. For additional information, go to http://nhd.usgs.gov. Additional datasets are used for small-scale hydrography representation as well​, including medium resolution NHDPlus published by EPA​; USGS Small-Scale hydrography; and bathymetry from ETOPO1 Global Relief, provided by NOAA National Centers for Environmental Information, U.S. Coastal Relief Model.

The National Water Quality Network (NWQN) for Rivers and Streams includes 113 surface-water river and stream sites monitored by the U.S. Geological Survey (USGS) National Water Quality Program (NWQP). The NWQN represents the consolidation of four historical national networks: the USGS National Water-Quality Assessment (NAWQA) Project, the USGS National Stream Quality Accounting Network (NASQAN), the National Monitoring Network (NMN), and the Hydrologic Benchmark Network (HBN). The NWQN includes 22 large river coastal sites, 41 large river inland sites, 30 wadeable stream reference sites, 10 wadeable stream urban sites, and 10 wadeable stream agricultural sites. In addition to the 113 NWQN sites, 3 large inland river monitoring sites from the USGS Cooperative Matching Funds (Co-op) program are also included in this annual water-quality reporting Web site to be consistent with previous USGS studies of nutrient transport in the Mississippi-Atchafalaya River Basin. This data release contains geo-referenced digital data and associated attributes of watershed boundaries for 113 NWQN and 3 Co-op sites. Two sites, "Wax Lake Outlet at Calumet, LA"; 07381590, and "Lower Atchafalaya River at Morgan City, LA"; 07381600, are outflow distributaries into the Gulf of Mexico. Watershed boundaries were delineated for the portion of the watersheds between "Red River near Alexandria, LA"; 07355500 and "Atchafalaya River at Melville, LA"; 07381495 to the two distributary sites respectively. Drainage area was undetermined for these two distributary sites because the main stream channel outflows into many smaller channels so that streamflow is no longer relative to the watershed area. NWQN watershed boundaries were derived from the Watershed Boundary Dataset-12-digit hydrologic units (WBD-12). The development of the WBD-12 was a coordinated effort between the United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS), the USGS, and the Environmental Protection Agency (EPA) (U.S. Department of Agriculture-Natural Resources Conservation Service, 2012). A hydrologic unit is a drainage area delineated to nest in a multi-level, hierarchical drainage system. Its boundaries are defined by hydrographic and topographic criteria that delineate an area of land upstream from a specific point on a river, stream or similar surface waters. The United States is divided and sub-divided into successively smaller hydrologic units identified by a unique hydrologic unit code (HUC) consisting of two to 12 digits based on the six levels of classification in the hydrologic unit system: regions, sub-regions, accounting units, cataloging units, watersheds, and sub-watersheds. NWQN watershed boundaries were delineated by selecting all sub-watershed polygons that flow into the most downstream WBD-12 polygon in which the NWQN site is located. The WBD-12 attribute table contains 8-digit, 10-digit, and 12-digit HUCs which were used to identify which sub-watersheds flow into the watershed pour point at the NWQN site location. When the NWQN site was located above the pour point of the most downstream sub-watershed, the sub-watershed was edited to make the NWQN site the pour point of that sub-watershed. To aid editing, USGS 1:24,000 digital topographic maps were used to determine the hydrologic divide from the sub-watershed boundary to the NWQN pour point. The number of sub-watersheds which are contained within the NWQN watersheds ranged from less than one to nearly 32,000 internal sub-watersheds. Internal sub-watershed boundaries were dissolved so that a single watershed boundary was generated for each NWQN watershed. Data from this release are presented at the USGS Tracking Water Quality page: http://cida.usgs.gov/quality/rivers/home (Deacon and others, 2015). Watershed boundaries delineated for this release do not take into account non-contributing area, diversions out of the watershed, or return flows into the watershed. Delineations are based solely on contributing WBD-12 polygons with modifications done only to the watershed boundary at the NWQN site location pour point. For this reason calculated drainage areas for these delineated watersheds may not match National Water Information System (MWIS) published drainage areas (http://dx.doi.org/10.5066/F7P55KJN). Deacon, J.R., Lee, C.J., Toccalino, P.L., Warren, M.P., Baker, N.T., Crawford, C.G., Gilliom, R.G., and Woodside, M.D., 2015, Tracking water-quality of the Nation’s rivers and streams, U.S. Geological Survey Web page: http://cida.usgs.gov/quality/rivers, https://dx.doi.org/doi:10.5066/F70G3H51. U.S. Department of Agriculture-Natural Resources Conservation Service, 2012, Watershed Boundary Dataset-12-digit hydrologic units: NRCS National Cartography and Geospatial Center, Fort Worth, Tex., WBDHU12_10May2012_9.3 version, accessed June 2012 at http://datagateway.nrcs.usda.gov.

This is a tiled collection of the 3D Elevation Program (3DEP) and is one meter resolution. The 3DEP data holdings serve as the elevation layer of The National Map, and provide foundational elevation information for earth science studies and mapping applications in the United States. Scientists and resource managers use 3DEP data for hydrologic modeling, resource monitoring, mapping and visualization, and many other applications. The elevations in this DEM represent the topographic bare-earth surface. USGS standard one-meter DEMs are produced exclusively from high resolution light detection and ranging (lidar) source data of one-meter or higher resolution. One-meter DEM surfaces are seamless within collection projects, but, not necessarily seamless across projects. The spatial reference used for tiles of the one-meter DEM within the conterminous United States (CONUS) is Universal Transverse Mercator (UTM) in units of meters, and in conformance with the North American Datum of 1983 ...

Abstract: This file contains Hydrologic Unit (HU) polygon boundaries for the United States, Puerto Rico, and the U.S. Virgin Islands. The data is a seamless National representation of HU boundaries from 2 to 14 digits compiled from U.S. Geological Survey (USGS) National Hydrography Dataset (NHD) and U.S. Department of Agriculture (USDA) National Resources Conservation Service (NRCS) Watershed Boundary Dataset (WBD) sources. Purpose: This data is intended primarily for geographic display and analysis of regional and national data, and can also be used for illustration purposes at intermediate or small scales (1:250,000 to 1:2,000,000). See https://apps.nationalmap.gov/help/ for assistance with The National Map viewer, download client, services, or metadata.

USGS developed The National Map Gazetteer as the Federal and national standard (ANSI INCITS 446-2008) for geographic nomenclature based on the Geographic Names Information System (GNIS). The National Map Gazetteer contains information about physical and cultural geographic features, geographic areas, and locational entities that are generally recognizable and locatable by name (have achieved some landmark status) and are of interest to any level of government or to the public for any purpose that would lead to the representation of the feature in printed or electronic maps and/or geographic information systems. The dataset includes features of all types in the United States, its associated areas, and Antarctica, current and historical, but not including roads and highways. The dataset holds the federally recognized name of each feature and defines the feature location by state, county, USGS topographic map, and geographic coordinates. Other attributes include names or spellings other than the official name, feature classification, and historical and descriptive information. The dataset assigns a unique, permanent feature identifier, the Feature ID, as a standard Federal key for accessing, integrating, or reconciling feature data from multiple data sets. This dataset is a flat model, establishing no relationships between features, such as hierarchical, spatial, jurisdictional, organizational, administrative, or in any other manner. As an integral part of The National Map, the Gazetteer collects data from a broad program of partnerships with federal, state, and local government agencies and other authorized contributors. The Gazetteer provides data to all levels of government and to the public, as well as to numerous applications through a web query site, web map, feature and XML services, file download services, and customized files upon request. The National Map download client allows free downloads of public domain geographic names data by state in a pipe-delimited text format. For additional information on the GNIS, go to https://www.usgs.gov/tools/geographic-names-information-system-gnis. See https://apps.nationalmap.gov/help/ for assistance with The National Map viewer, download client, services, or metadata. Data Refreshed March, 2025

This United States Geological Survey (USGS) web map displays the National Watershed Boundary Dataset (WBD). It defines the perimeter of drainage areas formed by the terrain and other landscape characteristics. The drainage areas are nested within each other so that a large drainage area (Upper Mississippi River), will be composed of multiple smaller drainage areas like the Wisconsin River. Each of these smaller areas can be further subdivided into subsequently smaller drainage areas.The intent of defining hydrologic units (HU) for the WBD is to establish a base-line drainage boundary framework, accounting for all land and surface areas. The WBD is a comprehensive aggregated collection of HU data consistent with the national criteria for delineation and resolution. Each HU is identified by a unique hydrologic unit code (HUC). This service includes HU boundaries for HUC2 (Hydrologic unit boundary), HUC4 (Region), HUC6 (Subregion), HUC8 (Basin), HUC10 (Sub-basin) and HUC12 (Watershed). Pop-ups include HUC name, HUC code and the states that are included in each HU.More information about the WBD can be found at the WBD information site.Click here for information on the Federal Standards and Procedures for the National Watershed Boundary Dataset.Data for this service can be found here._Other Federal User Community federally focused content that may interest youDepartment of the Interior U.S Geological Survey

This dataset represents all Streamgage Monitoring Stations from the U.S. Geological Survey, for the United States, Puerto Rico, and the U.S. Virgin Islands, in 2025. Gaging stations, or gages, measure the height (stage) and volume of flow at a point location on a water feature. Gages in this map layer were drawn from the National Water Information System (NWIS) Web Interface and linked to the National Hydrography Dataset Plus Version 2 (NHDPlusV2) flowline feature class. Each Streamgage point contains a link to the USGS Water Data site, which provides daily statistics reported from the station.Data pulled from GeoJSON: Release Rebuild with latest NWIS · internetofwater/ref_gages · GitHubThe GeoJSON file references NHDPlusV2 identifiers and the “reference mainstems” which are governed here:https://github.com/internetofwater/ref_rivers/

In 2012 a joint project was started by the Milwaukee Metropolitan Sewerage District (MMSD) and University of Wisconsin –Milwaukee (UWM) to support MMSD’s Integrated Regional Stormwater Management Program. Digital copies of scans of various historical map sources were collected and georeferenced to Wisconsin State Plane Coordinate Systems (NAD 1927 and NAD 1983). Historical streams and water features in the Milwaukee area were mapped to a geographic information system (GIS). Water features were identified and digitized from the scanned source maps. These features included: Stream lines River lines Lake Michigan Shoreline Pond boundaries Lake boundaries Swamp or marsh boundaries Spring locations An Esri ArcGIS geodatabase was created to house the digitized features and associated attributes as delineated in the scanned source maps. Geographic coverage area: Milwaukee County; Portions of Waukesha, Ozaukee, Washington, and Racine CountySource map used for this data: U.S. Geological Survey, 1901-1906, USGS Historical Topographic Quadrangle Maps, available at https://www.usgs.gov/programs/national-geospatial-program/historical-topographic-maps-preserving-past.

This datasets contain GIS files related to the hydrology and watersheds of Accomack and Northampton Counties on the Eastern Shore of Virginia. Data include named and unnamed water bodies, rivers and streams (both center flowlines and area polygons showing bank-full width for larger features), wetlands and marshes, and shorelines. A static (2013-09-06) copy of the full USGS "National Hydrography Dataset (NHD) - High Resolution - Virginia" state-extracted dataset in original ESRI file-geodatabase format, downloaded on 2014-02-21 from nhd.usgs.gov, is included. For users who may not be able to read or make use of data in ESRI proprietary geodatabase formats, shapefiles of geographic feature classes contained within the HUC8 subbasins spanning Accomack and Northampton Counties (partly or wholly) are also provided. Note that the stream network nodal topology, which can be used to evaluate and analyze flow paths as part of a fully-functional hydrological network with GIS tools such as Arc Hydro and Network Analyst, are only available within the ESRI file-geodatabase file. The primary purpose of this dataset is to provide VCRLTER researchers and students with a convenient up-to-date set of GIS data layers in one location that can be used as base layers for various map products and for conducting research activities. A secondary purpose of this dataset is to extend hydrologic data coverage in the VCRLTER data catalog to include Accomack County and to supersede older USGS DLG data contained in the Northampton County GIS data package (VCRLTER dataset VCR14219).

This high-level metadata data document will be supplemented with detailed regional metadata at a later date. The NHDPlusV2 is an integrated suite of application-ready geospatial data sets that incorporate many of the best features of the National Hydrography Dataset (NHD) and the National Elevation Dataset (NED). Interest in estimating stream flow volume and velocity to support pollutant fate-and-transport modeling was the driver behind the joint USEPA and USGS effort to develop the initial NHDPlus, referenced in this document as NHDPlusV1. NHDPlusV1 has been used in a wide variety of applications since its initial release in the fall of 2006. This widespread positive response prompted the multi-agency NHDPlus team to develop NHDPlus Version 2 (NHDPlusV2). The NHDPlusV2 includes a stream network (based on the 1:100,000-scale NHD), improved networking, naming, and "value-added attributes" (VAA's). NHDPlusV2 also includes elevation-derived catchments (drainage areas) produced using a drainage enforcement technique first broadly applied in New England, and thus dubbed "The New-England Method". This technique involves "burning-in" the 1:100,000-scale NHD and building "walls" using the national Watershed Boundary Dataset (WBD). The hydro-enforced digital elevation model (DEM) is used to produce hydrologic derivatives that agree with the NHD and WBD. An interdisciplinary team from the USGS, USEPA and contractors, has found this method to produce the best quality NHD catchments using an automated process. The VAAs include greatly enhanced capabilities for upstream and downstream navigation, analysis and modeling. Examples include: retrieve all flowlines (predominantly confluence-to-confluence stream segments) and catchments upstream of a given flowline using queries rather than by slower flowline-by-flowline navigation; retrieve flowlines by stream order; select a stream level path sorted in hydrologic order for stream profile mapping, analysis and plotting; and, calculate cumulative catchment attributes using streamlined VAA hydrologic sequencing routing attributes. The VAAs include results from the use of these cumulative routing techniques, including cumulative drainage areas, precipitation, temperature, and runoff distributions. Several of these cumulative attributes are used to estimate mean annual flow and velocity as part of the VAAs. NHDPlusV2 contains a snapshot (2012) of the 1:100,000-scale NHD that has been extensively improved over the snapshot used in NHDPlusV1. While these updates will eventually be stored in the central NHD repository at USGS, this will not be accomplished prior to distribution of NHDPlusV2. NHDPlusV2 users may not make updates to the NHD portions of NHDPlusV2 with the intent of sending these updates back to the USGS. Updates to the 1:100,000-scale NHD snapshot in NHDPlusV2 should be sent to the USEPA as the primary steward. Purpose: The geospatial data sets included in NHDPlusV2 are intended to support a variety of water-related applications. They already have been used in an application to develop estimates of mean annual streamflow and velocity for each NHDFlowline feature in the conterminous United States. The results of these analyses are included with the NHDPlusV2 data. NHDPlusV2 serves as the sample frame for the stream and lake surveys conducted by the USEPA under the National Aquatic Resources Surveys program. A water-quality model developed by the U.S. Geological Survey (USGS) called SPARROW (Spatially Referenced Regressions on Watershed Attributes), can utilizes the NHDPlusV2 network functionality to track the downstream transport of nutrients, sediments, or other substances. NHDPlusV2 water bodies and estimates of streamflow and velocity are used in SPARROW to identify reservoir retention and in-stream loss factors. NHDPlusV2 climatic and land surface attributes can be used in SPARROW to identify potential factors in the delivery of nutrients from the land surface to streams. NHDPlusV2 data is also being used in select areas for a USGS Web-based application, called StreamStats. StreamStats provides tools to interactively select any point in the implemented areas, delineate watersheds, and to obtain streamflow and watershed characteristics for the selected point. NHDPlusV2 has been designed to accommodate many users' needs for future applications. NHDPlusV2 provides the framework and tools necessary to customize the behavior of the network relationships as well as building upon the attribute database, for which the user can assign their own data to the network.

This dataset adds attributes describing the self-calibrated Palmer Drought Severity Index (PDSI) during the observation year of wet/dry streamflow observations collected in the Pacific Northwest, USA. Streamflow observation locations are linked to the nearest National Hydrography Dataset high-resolution (NHD-HR) stream segment to obtain stream order and stream permanence (perennial/non-perennial) from NHD-HR. Additionally, the PDSI and precipitation percentile for 7.5 minute quadrangle map extents, within the extent of the conterminous United States (https://carto.nationalmap.gov/arcgis/rest/services/map_indices/MapServer), during the map survey year are presented. NHD perennial/non-perennial classifications derive from the topographic maps.

Digital flood-inundation maps were created for a 7.1-mile reach of the North Fork Kentucky River at Hazard, Kentucky. The flood-inundation maps, which can be accessed through the U.S. Geological Survey (USGS) Flood Inundation Mapping Science website at https://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage on the North Fork Kentucky River at Hazard, Kentucky (USGS station number 03277500). Near-real-time stages at this streamgage may be obtained on the Internet from the USGS National Water Information System at https://waterdata.usgs.gov/ or the National Weather Service (NWS) Advanced Hydrologic Prediction Service (AHPS) at https://water.weather.gov/ahps/, which also forecasts flood hydrographs at this site (NWS AHPS site HAZK2). The NWS AHPS forecast peak stage information may be used with the maps developed in this study to show predicted areas of flood inunda ...

This dataset displays the 12-digit Hydrologic Unit (HUC 12) divides from the Watershed Boundary Dataset (WBD) were used as ridgeline enforcement input in a process called "walling" in the production of hydro-enforced DEMs. Closed basin designations, from the HUC 12 polygon data were used to impose "sinks" in the hydro-enforced DEMs. These DEMs are the source data from which NHDPlus HR Catchments are delineated from. Catchments with corresponding boundaries in the WBD generally agree with the WBD to within one or two 10-m grid cells. Some larger differences between catchment boundaries and WBD boundaries do exist, however. NHDPlus HR Flow Direction and Accumulation Grids are hydrologic derivative products of the hydro-enforced DEMs. Dates of WBD snapshots used were as follows: August 31, 2010 - VPU 04 March 10, 2011 - VPUs 05, 06 July 14, 2011 - VPU 17 September 16, 2011 - VPU 10L October 7, 2011 - VPU10U November 14, 2011 - VPUs 07, 11 December 2, 2011- VPU 18 December 21, 2011 - VPUs 09, 12 February 1, 2012 - VPUs 01, 02, 03N,03S, 03W, 08, 13, 14, 15, 16 October 2014 - VPUs 20, 21 April 2015 - VPUs 22AS, 22GU, 22MP The February 1, 2012 WBD snapshot used to migrate NHD medium resolution Reach code assignment to agree with WBD HUC 8 codes. Reach codes in VPUs 20, 21, 22AS, 22GU, and22MP agree with their WBD Snapshots.WBD is included in the National Hydrography Dataset Plus High Resolution (NHDPlus HR) for Hydrologic Unit 1204 dataset published by United States Geological Survey (USGS). https://nhd.usgs.gov

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” (http://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, 1:25,000-scale in Hawaii, Pacific basin and the Caribbean, and 1:63,360-scale in Alaska, 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. Some GNIS names in this data are offensive so the word “Negro” has been replaced with the hydrologic unit code while the process of reviewing and changing the names is ongoing through official channels.

The U.S. Geological Survey (USGS) collected hydroacoustic data of the St. Croix River adjacent to the Osceola (WI) boat ramp for hydrographic and benthic mapping prior to the reconstruction project implemented by the National Park Service (NPS). This dataset contains predicted geologic substrate information that was interpreted from combined sonar datasets. The shapefile contains a general description of interpreted surficial bottom type with its associated class code in the attribute table. Benthic substrate maps provide important physical characteristics that can be used in habitat modeling to guide management planning of restoration and conservation efforts.

This digital elevation model (DEM) is a part of a series of DEMs produced for the National Oceanic and Atmospheric Administration Coastal Services Center's Sea Level Rise and Coastal Flooding Impacts Viewer. The DEM includes the 'best available' lidar data known to exist at the time of DEM creation that meets project specifications for those counties within the boundary of the Corpus Christi TX Weather Forecast Office (WFO), as defined by the NOAA National Weather Service. The counties within this boundary are: Kleberg, Nueces, San Patricio, Aransas, Refugio, Victoria, and Calhoun.For all counties, except for Kleberg, the DEM is derived from LiDAR data sets collected for the Texas Water Development Board (TWDB) in 2005 and 2006 with a point density of 1.4 m GSD. The LiDAR data for Kleberg County is based on the US Geological Survey (USGS) National Elevation Dataset (NED) 1/9 arc-second elevation data. Hydrographic breaklines used in the creation of the DEM were delineated using LiDAR intensity imagery generated from the data sets. Hydrography for Kleberg County is based on the National Hydrography Dataset (NHD) and the National Wetlands Inventory (NWI). The DEM is hydro flattened such that water elevations are less than or equal to 0 meters.The DEM is referenced vertically to the North American Vertical Datum of 1988 (NAVD88) with vertical units of meters and horizontally to the North American Datum of 1983 (NAD83). The resolution of the DEM is approximately 10 meters.The DEM includes the best available lidar data known to exist at the time of DEM creation for the coastal areas of Victoria, Calhoun, Aransas, Refugio, San Patricio, Nueces, and Kleberg counties.