The following tools are provided to assist in the use of NHD data. Any problems encountered when using these tools should be reported to email@example.com. No special tool is needed to display or work with the NHD other than a GIS. The NHD is a GIS dataset available in a shapefile format. Any GIS that can read shapefiles can be used to display the NHD. Some features of the NHD, such as geometric navigation, only work within the Esri ArcMap software. An alternative to working with a GIS is to display the NHD in The National Map Viewer on the web. To do this, click on Get Data > Go to the NHD Viewer.
NHD GeoConflation Tool
The GeoConflation Tool is one of several methods available to update the National Hydrography Dataset (NHD). The tool automates the NHD Create Process used to generate the high resolution (24K) NHD data from the medium resolution (100K) data. NHD conflation is the integration of two datasets into one. The basic goal of conflation is to conserve ReachCodes and ComID’s by duplicating them from the original dataset to the modified or target dataset whenever possible. This allows the history of the ReachCodes, and by association any information tied to the ReachCode, to be preserved.
One way to think of the process is "change detection". There are two inputs to the tool: the original NHD subbasin and the newly created or updated geometry called the target subbasin. The source NHD subbasin is then compared to the target subbasin. Where the geometries of flowlines and/or waterbodies match within specified tolerances, ReachCodes and ComIDs are automatically transferred from the source NHD to the target dataset. Close matches are flagged for closer review by the user to determine if there is an actual match or not. If the feature exists in the original, but not in the target, a “delete feature” is automatically generated. In the alternative circumstance where the feature exists in the target but not the source, a new ReachCode and ComID is applied to the feature and a “create new feature” is automatically generated.
As in any update process the results are only as good as the input data. The updates or target data must have FTypes, FCodes, connectivity, and be in correct the NHD schema. In addition, the target data must pass all QA/QC checks required before any data is integrated into the NHD. The end result of the conflation process is a “new” dataset consisting of the new geometry complete with ReachCodes and ComIDs. All changes have been tracked. The updates are then uploaded to the database. In the near future, the new PermID and Crosswalk tables will be incorporated into the tool.
For more information about NHD Conflation, contact us at NHD-GCT@usgs.gov.
USFS Reprojection Tool Version 2
The USFS Reprojection Toolbar changes geographic projection and can transform datums using all available ESRI ArcObjects algorithms. It was developed by the USDA-Forest Service for the National Hydrography Dataset (NHD) NHDinGEO format, but can function on any personal or file geodatabase. This is an add-on toolbar written for ESRI's ArcGIS 9.2, 9.3, and 10. The advantage is that it reprojects whole personal and file geodatabases at once, and updates the metadata at both the Geodatabase, Dataset, and Feature class levels in both the Data Quality and Spatial Reference sections of standard FGDC metadata--or creates its own metadata if there is none. Version 2.0 works on ArcGIS 9.2 while version 2.1 works on ArcGIS 9.3, 2.2 works on ArcGIS 10.
Developer: U.S. Forest Service - Natural Resource Information System
Software Environment: ArcGIS 9.2, 9.3, 10
Purpose: The USFS Reprojection Toolbar changes geographic projection and can transform datum using all available ESRI ArcObjects model algorithms. This is an add-on toolbar written for ESRI's ArcGIS 9.2, 9.3 and 10. Once a geodatabase is highlighted and the toolbar's button is pushed, a user interface appears. User must name a new output personal geodatabase, and select the desired projection and datum. A progress report at the lower left corner of ArcCatalog shows current status at all times during processing. FGDC compliant metadata is updated in both the Data Quality Information and the Spatial Reference Information sections. To reproject, the NHD network must be deleted first and then rebuilt after the reprojection is complete. The "NHD Network Builder" can be downloaded at: http://nhd.usgs.gov/tools.html.
Loading and Installing:
Get the appropriate version at ftp://ftp2.fs.fed.us/incoming/wo/nris/water_abat/Reprojection_Tool_v2/
For more information on ESRI AddIns http://blogs.esri.com/Dev/blogs/arcgisdesktop/archive/2010/05/05/Add_2D00_ins-for-ArcGIS-Desktop-10.aspx
Hydrography Event Management Tool
The Hydrography Event Management (HEM) Tool provides full functionality for adding and editing events in the NHD. Events are informational data that are linked to the NHD using a linear referencing system on NHDFlowlines. The use of events is a key characteristic of the NHD by allowing vast amounts of scientific information to be linked to the NHD while keeping the design simple and by making advanced analysis techniques possible. The HEM tool handles all the linear referencing mechanics to make working with events easy. It works on point, line, and area events and allows events to be located interactively, imported, or calculated. A Source Feature ID is created that provides the link between the event location and the informational data tied to the location. It also creates metadata linked to the event. The tool also provides network measuring to determine distances through the NHDFlowline network. The most current release of the tool is for ArcGIS 10.1 and NHD version 2.1.
Developer: Department of the Interior - Bureau of Land Management
Software Environment: ArcGIS 9.3, 10.0 or 10.1
*All posted versions are for NHD version 2.1. To access HEM Tool versions prior to NHD v2.1 please contact HEM@usgs.gov.
Request HEM Tools User Support
Please contact HEM@usgs.gov.
HEM Training Request/Registration
Please contact HEM@usgs.gov to register.
HEM Training Materials
HEM EPA Add-on Tools
The U.S. Environmental Protection Agency (EPA) has developed a supplemental set of indexing functions for the HEM, which are available through the HEM EPA Add‐Ons toolbar. This toolbar allows users to create, edit and manage custom point, line and area events. The toolbar also includes functionality that was previously a part of the PC based Reach Indexing Tool (PC-RIT), such as Find Overlapping Waterbodies, Extract from EPA Program Events, and a post processing tool to aid in preparing events for submission to the EPA's Reach Address Database (RAD). For a complete list of HEM EPA Add-on tools please download the HEM EPA Add-On Tools flyer.
Developer: EPA Office of Water
Software Environment: ArcGIS 9.3, 10.0 and 10.1
EPA Add-On Tools Download
EPA Add-On Tools Support
To request user support or technical assistance for the EPA Add-on Tools, please send an email to: firstname.lastname@example.org.
EPA Add-On Tools Training Materials
NHD Build Flow
The NHD Build Flow utility requires the input of an NHD subbasin personal or file geodatabase. The tool builds a geometric network using the NHDFlowline feature class within the geodatabase. Each node within the geometric network represents a confluence of two or more hydrography features less than 40 feet wide. The Build Flow utility then uses these nodes to populate the NHDFlow table with in and out flow directions for each node, based off the FlowDir attribute within the NHDFlowline feature class. The result is a populated NHDFlow table that shows the flow of water throughout the subbasin.
Use: Open the tool, select an NHD geodatabase and then press OK.
NHD Network Builder
Software Environment: NHD Network Builder runs under ArcGIS 9.3x, 10, and 10.1
Purpose: The NHD Network Builder builds a personal geodatabase (mdb) or File geodatabase (gdb) network and sets the flow direction as per the 'Flowdir' field of the 'NHDFlowline' feature class.
Important Details: This application is only intended to rebuild the network on NHDinGEO data that has already been prepared for networking. It is normally used when rebuilding a network after the NHDinGEO has been projected.
Downloading and Installing: To download NHD Network Builder, click on the link below using your right mouse button and choose 'Save Link As...' or 'Save Target As...' (depending on your browser). This allows you to save the file on your PC's hard drive.
To install NHD Network Builder on a PC: Copy the executable to your hard drive. This need not be the directory containing the NHDinGEO data. The full help documentation/discussion is in the toolbar and may be saved as a Microsoft .rtf file.
Using NHD Network Builder: Once you have installed the software, it can be used to rebuild the geometric network for NHD data. Go to start – All programs - . Browse to the file ex: C:\Yellowstone\Yellowstone.mdb. Click on the Build Network button. A second window will appear indicating when the network is built.
Software Environment: NHD MValue Utility runs under ArcGIS 9.3x, NHD Model v 2.1, Windows XP/7
Purpose: M Values, or measures, are the percentage upstream a given location is on an NHDflowline. Measures range from 0-100 percent with 0 being the most downstream point of a reach, and 100 being the most upstream end. This is opposite of the flow/digitized direction of the feature. The MValue Utillity builds MValues on NHD reached flowlines. Each reached flowline feature will have MValues associated with it. The MValue provides the networked location of a point event or the extent of a linear event along a reach.
Using MValues Utility: NHDMValue_Utility.ppt
PGDB2ShpConverts NHD ESRI personal or file geodatabases to a shapefile.
Shp2PGDBConverts an NHD Shapefile to a an ESRI file geodatabase.
XML2GDBUsed in the process for NHD Conflation. For more information on Conflation see http://nhd.usgs.gov/tools.html#conflation
XMLExtractUsed in the process for NHD Conflation. For more information on Conflation see http://nhd.usgs.gov/tools.html#conflation
NHD Merge Tool
Software Environment: The Merge program runs under ArcGIS 10.0 and data in 9.3.1 format.
Purpose: The Merge program was developed to join two or more NHD file geodatabases and generating one file geodatabase as the output. The program will also remove duplicated features between input files.
Some of the documents found on this page are presented in Portable Document Format (PDF); the latest version of Adobe Acrobat Reader or similar software is required to view it. Download the latest version of Acrobat Reader, free of charge.