National Hydrography Dataset Plus (NHDPlus)

Description

The NHDPlus Version 1.0 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). The NHDPlus includes a stream network (based on the 1:100,000-scale NHD), improved networking, naming, and "value-added attributes" (VAA's). NHDPlus also includes elevation-derived catchments (drainage areas) produced using a drainageenforcement 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 when available building "walls" using the national WatershedBoundary Dataset (WBD). The resulting modified digital elevation model(HydroDEM) is used to produce hydrologic derivatives that agree with the NHDand WBD. An interdisciplinary team from the U. S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), and contractors, over the lasttwo years 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; subset 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 land cover distributions. Several of these cumulative attributes are used to estimate mean annual flow and velocity as part of the VAAs.NHDPlus contains a snapshot (2005) of the 1:100,000-scale NHD that has been extensively improved. While these updates will eventually make their way back to the central NHD repository at USGS, this will not have happened prior to distribution of NHDPlus because the update process for the central NHD repository is still in development. Consequently, the NHDPlus will contain some temporary database keys and, as a result, NHDPlus users may not make updates to the NHD portions of NHDPlus with the intent of sending these updates back to the USGS. Once the NHDPlus updates have been posted to the central NHD repository, a fresh copy of the improved data can be downloaded from the central NHD repository and that copy will be usable for data maintenance. Note that the NHDPlus products are tightly integrated and user modifications to the underlying NHD can compromise this synchronization.

General Information

• This data is described at

  http://catalog.data.gov/dataset/national-hydrography-dataset-plus-nhdplus Do you think this data is incorrect? Let us know

• This data is published by

  U.S. Environmental Protection Agency Do you think this data is incorrect? Let us know

Legal Information

• The rights statement is at

  http://catalog.data.gov/dataset/national-hydrography-dataset-plus-nhdplus Do you think this data is incorrect? Let us know

• Outside the US, this data is available under

  Creative Commons CCZero Do you think this data is incorrect? Let us know

• There are

  yes, and the rights are all held by the same person or organisation Do you think this data is incorrect? Let us know

• The content is available under

  Creative Commons CCZero Do you think this data is incorrect? Let us know

• This data contains

  no data about individuals Do you think this data is incorrect? Let us know

Practical Information

• The data appears in this collection

  http://catalog.data.gov/organization/epa-gov Do you think this data is incorrect? Let us know

• The accuracy or relevance of this data will

  go out of date but it is timestamped Do you think this data is incorrect? Let us know

• The data is

  backed up offsite Do you think this data is incorrect? Let us know

Technical Information

• This data is published at

  http://www.epa.gov/waters Do you think this data is incorrect? Let us know

Social Information

• The documentation includes machine-readable data for

  title Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  description Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  identifier Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  landing page Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  release frequency Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  publisher Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  distribution(s) Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  release date Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  modification date Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  temporal coverage Do you think this data is incorrect? Let us know

• The documentation includes machine-readable data for

  spatial/geographical coverage Do you think this data is incorrect? Let us know

• The documentation about each distribution includes machine-readable data for

  release date Do you think this data is incorrect? Let us know

• The documentation about each distribution includes machine-readable data for

  a URL to access the data Do you think this data is incorrect? Let us know

• The documentation about each distribution includes machine-readable data for

  a URL to download the dataset Do you think this data is incorrect? Let us know

• Find out how to contact someone about this data at

  http://catalog.data.gov/dataset/national-hydrography-dataset-plus-nhdplus Do you think this data is incorrect? Let us know

• Find out how to suggest improvements to publication at

  http://www.data.gov/issue/?media_url=http://catalog.data.gov/dataset/national-hydrography-dataset-plus-nhdplus Do you think this data is incorrect? Let us know