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 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.

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.

National Hydrologic Dataset downloaded from USGS on 2/4/2022. This data is also available from the USGS as a service at https://hydro.nationalmap.gov/arcgis/rest/services/nhd/MapServerAbstract: 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. Use the metadata link, http://nhdgeo.usgs.gov/metadata/nhd_high.htm, for additional information. Purpose: The NHD is a national framework for assigning reach addresses to water-related entities, such as industrial discharges, drinking water supplies, fish habitat areas, wild and scenic rivers. Reach addresses establish the locations of these entities relative to one another within the NHD surface water drainage network, much like addresses on streets. Once linked to the NHD by their reach addresses, the upstream/downstream relationships of these water-related entities--and any associated information about them--can be analyzed using software tools ranging from spreadsheets to geographic information systems (GIS). GIS can also be used to combine NHD-based network analysis with other data layers, such as soils, land use and population, to help understand and display their respective effects upon one another. Furthermore, because the NHD provides a nationally consistent framework for addressing and analysis, water-related information linked to reach addresses by one organization (national, state, local) can be shared with other organizations and easily integrated into many different types of applications to the benefit of all.

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.

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.

A map service depicting modeled streamflow metrics from the historical time period (1977-2006) in the United States. In addition to standard NHD attributes, the streamflow datasets include metrics on mean daily flow (annual and seasonal), flood levels associated with 1.5-year, 10-year, and 25-year floods; annual and decadal minimum weekly flows and date of minimum weekly flow, center of flow mass date; baseflow index, and average number of winter floods. These files and additional information are available on the project website, https://www.fs.usda.gov/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml. Streams without flow metrics (null values) were removed from this dataset to improve display speed; to see all stream lines, use an NHD flowline dataset.The flow regime is of fundamental importance in determining the physical and ecological characteristics of a river or stream, but actual flow measurements are only available for a small minority of stream segments, mostly on large rivers. Flows for all other streams must be extrapolated or modeled. Modeling is also necessary to estimate flow regimes under future climate conditions. Climate data such as this dataset is valuable for planning and monitoring purposes. Business use cases include: climate change and water rights assessments; analysis of water availability, runoff, groundwater, and impacts to aquatic organisms; resource management; post fire recovery; restoration activities, etc.Hydro flow metrics data can be downloaded from here.This feature layer contains a series of fields from the NHD, including the COMID , which provides a unique identifier for each NHD stream segment, as well as other basic hydrological information. It also contains the Region field, which indicates the NHD region (2-digit hydrologic unit codes) or a subdivision of regions based on NHDPlus production units (https://www.horizon-systems.com/NHDPlus/). Production units are designated by letters appended to the region code, such as 10U (the upper Missouri River basin). Additional documentation about this dataset is located in the data user guide. A StoryMap including a map viewer and map exporter by forest/region is also available. Additional climate and streamflow products from the Office of Sustainability and Climate are available in our Climate Gallery.This dataset contains the following data layers:Mean annual flow: calculated as the mean of the yearly discharge valuesMean spring flow: calculated as the mean of the March/April/May discharge values, weighted by the number of days per monthMean summer flow: calculated as the mean of the June/July/August discharge values, weighted by the number of days per monthMean autumn flow: calculated as the mean of the September/October/November discharge values, weighted by the number of days per monthMean winter flow: calculated as the mean of the December/January/February discharge values, weighted by the number of days per month1.5-year flood: calculated by first finding the greatest daily flow from each year; the 33rd percentile of the annual maximum series defines the flow that occurs every 1.5 years, on average10-year flood: the flow that occurs every 10 years, on average, calculated as the 90th percentile of the annual maximum series25-year flood: the flow that occurs every 25 years, on average, calculated as the 96th percentile of the annual maximum series1-year minimum weekly flow: the average across years of the lowest 7-day flow during each year. Year is defined either as January/December or June/May, whichever has a lower standard deviation in the date of the low-flow week. This was done so that, for example, in areas with winter droughts, a December to January drought would not be split up by the start of a new year.10-year minimum weekly flow: average lowest 7-day flow during a decade (calculated as the 10th percentile of the annual minimum weekly flows)Date of minimum weekly flow: average date of the center of the lowest 7-day flow of the year, with 'year' defined either as January/December or June/May, whichever has a lower standard deviation in the date of the low-flow week. This was done to prevent erroneous results when the drought season crosses the break between years: e.g., if the lowest flow was on December 31 of the first year (day #365) and January 1 of the second year (day #1), this would give an average of day #183, July 2nd; switching the range of months in this case prevents this error.Baseflow index: the ratio of the average daily flow during the lowest 7-day flow of the year to the average daily flow during the year overall; this can be used as a rough estimate of the proportion of streamflow originating from groundwater discharge, rather than from recent precipitationCenter of flow mass/center of timing: calculated using a weighted mean: CFM=(flow1*1+flow2*2+ flow365*365)/(flow1+flow2+ flow365) where flowi is the flow volume on day i of the water year. This can be used to indicate areas where most of the precipitation occurs early in the water year (fall), or later (spring/summer).Number of winter floods: calculated as the average number of daily flows between December 1 and March 31 that exceed the 95th percentile of daily flows across the entire year

To provide an alternative to the native NHD measuring system of percentage of distance along reach length with one that enhances the ability to examine distance relationships along entire stream courses.

This map service represents modeled streamflow metrics from the mid-century time period (2030-2059) in the United States. In addition to standard NHD attributes, the streamflow datasets include metrics on mean daily flow (annual and seasonal), flood levels associated with 1.5-year, 10-year, and 25-year floods; annual and decadal minimum weekly flows and date of minimum weekly flow, center of flow mass date; baseflow index, and average number of winter floods. These files and additional information are available on the project website, https://www.fs.usda.gov/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml. Streams without flow metrics (null values) were removed from this dataset to improve display speed; to see all stream lines, use an NHD flowline dataset.Hydro flow metrics data can be downloaded from here.

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 map service represents the percent change in modeled streamflow metrics between the historical (1977-2006) and mid-century (2030-2059) time periods in the United States. In addition to standard NHD attributes, the streamflow datasets include metrics on mean daily flow (annual and seasonal), flood levels associated with 1.5-year, 10-year, and 25-year floods; annual and decadal minimum weekly flows and date of minimum weekly flow, center of flow mass date; baseflow index, and average number of winter floods.�These files and additional information are available on the project website,�https://www.fs.usda.gov/rm/boise/AWAE/projects/modeled_stream_flow_metrics.shtml. Streams without flow metrics (null values) were removed from this dataset to improve display speed; to see all stream lines, use an NHD flowline dataset.Hydro flow metrics data can be downloaded from�here.

Canals and streams (AHED HydroEdges) are the network of lines describing the map hydrography. The HydroEdge feature class was populated using the 1:24000 National Hydrography Dataset (NHD). There are two subtypes of HydroEdges: Flowline, which traces water movement, and Shoreline, which forms the interface between land and water where it is not defined by a waterbody polygon. HydroEdge geometry for primary and secondary and some local features has been edited for correctness using the District's aerial imagery. According to the Arc Hydro Model, the end points of HydroEdges are always covered by point features called HydroJunctions.

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.

A subset of the USGS National Hydro Dataset (NHD) containing only blueline streams. 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.

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 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 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

Available water supply varies greatly across the United States depending on topography, climate, elevation and geology. Forested and mountainous locations, such as national forests, tend to receive more precipitation than adjacent non-forested or low-lying areas. However, contributions of national forest lands to regional streamflow volumes is largely unknown. Using outputs from the Variable Infiltration Capacity hydrologic model, we calculated mean annual and mean summer (July and August) streamflow metrics based on total flow and flow from national forest lands for each 1:100,000 scale National Hydrography Dataset stream reach in the contiguous United States. Specifically, this data publication contains twenty-one comma-delimited ASCII text files (for different drainage areas and processing units across the United States) containing 1915-2011 mean annual flow and mean summer flow.Data can be downloaded here: Geodatabase or ShapefileThese files also contain the mean annual and mean summer flows from National Forest System (NFS) lands as well as the portion of total mean annual and summer flow contributed by flow from NFS lands.These data provide insight into 1915-2011 hydrologic regimes and national forest contributions to total water yield. These non-spatial files were then merged and joined to the September 2012 snapshot of the National Hydrography Dataset (NHD), version 2.Note: 'Forest Service lands' are here defined as those lands within the Forest Service administrative boundaries; these include some inholdings and other non-USFS lands enclosed within these boundaries.This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.

Available water supply varies greatly across the United States depending on topography, climate, elevation and geology. Forested and mountainous locations, such as national forests, tend to receive more precipitation than adjacent non-forested or low-lying areas. However, contributions of national forest lands to regional streamflow volumes is largely unknown. Using outputs from the Variable Infiltration Capacity hydrologic model, we calculated mean annual and mean summer (July and August) streamflow metrics based on total flow and flow from national forest lands for each 1:100,000 scale National Hydrography Dataset stream reach in the contiguous United States. Specifically, this data publication contains twenty-one comma-delimited ASCII text files (for different drainage areas and processing units across the United States) containing 1915-2011 mean annual flow and mean summer flow.Data can be downloaded here: Geodatabase or ShapefileThese files also contain the mean annual and mean summer flows from National Forest System (NFS) lands as well as the portion of total mean annual and summer flow contributed by flow from NFS lands.These data provide insight into 1915-2011 hydrologic regimes and national forest contributions to total water yield. These non-spatial files were then merged and joined to the September 2012 snapshot of the National Hydrography Dataset (NHD), version 2.Note: 'Forest Service lands' are here defined as those lands within the Forest Service administrative boundaries; these include some inholdings and other non-USFS lands enclosed within these boundaries.This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.