NHD

1:24,000 High Resolution

The National Hydrography Dataset (NHD) is a comprehensive set of digital spatial data that contains information about surface water features such as lakes, ponds, streams, rivers, springs and wells. Within the NHD, surface water features are combined to form "reaches," which provide the framework for linking water-related data to the NHD surface water drainage network. These linkages enable the analysis and display of these water-related data in upstream and downstream order.

The NHD is based upon the content of USGS Digital Line Graph (DLG) hydrography data integrated with reach-related information from the EPA Reach File Version 3 (RF3). The NHD supersedes DLG and RF3 by incorporating them, not by replacing them. Users of DLG or RF3 will find the National Hydrography Dataset both familiar and greatly expanded and refined.

While initially based on 1:100,000-scale data, the data for Mississippi has incorporated higher resolution ( 1:24,000) data required by many users.

For more information go to http://nhd.usgs.gov/

This NHD data is distributed as a set of shapefiles. This format is referred to as NHDGEOinSHP. Data is distributed by subbasin. (See Index Map)

MARIS is only distributing a subset of the entire NHD data. MARIS has extracted the three layers needed for cartographic purposes, not the other two used for modeling. For the entire data set, go to the link above.

Once you have unzipped the subbasin file, you should see the following files for the subbasin (53 cover Mississippi )

fl<subbasin> - nhdflowline shapefile - Streams, rivers, creeks, branches, flow lines
wb<subbasin> - nhdwaterbody shapfile – Lakes, Ponds, Swamps, Marsh
oa<subbasin> - nhdarea shapefile – Inundated areas, double-side streams areas

The data is stored in Latitude/Longitude - Datum NAD83

USGS Metadata

Use the FCODE file variable to determine type of element. Primarily,

FCODE = 46003 = Intermittent while FCODE = 46006 = Perennial

MARIS has plans to append the shapefiles, then clip on the new 1:24,000 county borders once the entire state is completed by USGS to form county hydrography data sets. Scheduled completion date for 03180004 is Sept 06. The expected completion date for 08030100 is Dec 06