Hydrography

National Hydrography Dataset and Watershed Boundary Dataset

The National Hydrography Dataset (NHD) and Watershed Boundary Dataset (WBD) are digital geospatial datasets that map the surface water of the United States.

The NHD represents the national drainage networks and related surface water features including rivers, streams, canals, lakes, ponds, glaciers, coastlines, dams, and stream gauges. The NHD has attributed these features and 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 including the direction of water flow. This network of reach codes allows analysis for tracing movement in upstream and downstream directions. The NHD can support many applications, such as making maps, geocoding observations, flow modeling, data maintenance, and stewardship.

The WBD represents drainage areas of the country in eight nested levels called hydrologic unit codes(HUCs).

Texas stretches across three HUC-2 regions encompassing the Arkansas-White-Red Region, Texas-Gulf Region and Rio Grande Region; furthermore, Texas contains over 6,450 HUC-12 Subwatershed. The NHD for Texas contains over 1.5 Million features.

USGS Markup Application for NHD Public Updates and Edits

The Markup Application is a web-based mapping tool allowing public users to submit edits, or markups, to the NHD, WBD, and NHDPlus HR. Users can log in with any gmail account to suggest corrections and improvements to the data using local knowledge. For more information and details on how to use the tool see the USGS new Markup App Video for help using the tool.

NHD Plus HR Beta

NHD Plus HR Beta is the newest iteration of the NHD product currently available for Texas. NHDPlus HR is comprised of a nationally seamless network of stream reaches, elevation-based catchment areas, flow surfaces, and value-added attributes that enhance stream network navigation, analysis, and data display.

In Texas NHD Plus HR is currently available for all regions of Texas and beta QC is either in progress or completed.

The NHDPlus HR is built using:

The National Hydrography Dataset High Resolution data at 1:24,000 scale or better

The 1/3 arc-second (10 meter ground spacing) 3D Elevation Program data

The complete nationwide Watershed Boundary Dataset NHDPlus HR consists
of vector and raster

data layers. It includes a snapshot of the NHD and WBD at the time the NHDPlus HR was built, as well as the following components:

A set of value added attributes, in addition to the standard NHD attributes, that enhance stream network navigation, analysis and display

An elevation-based catchment area for each flowline in the stream network

Catchment characteristics, including mean annual precipitation, mean annual temperature, and mean annual runoff, and mean latitude

Cumulative drainage area characteristics

Mean annual flow (1971-2000) and velocity estimates for each flowline in the stream network

Flow direction, flow accumulation, elevation, and hydro-enforced elevation rasters

Headwater node areas

Flowline min/max elevations and slopes