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Hydrography Event Management (HEM) Tool Announcement

EPA is pleased to announce the availability of a new reach indexing tool called the Hydrography Event Management (HEM) tool. The HEM Tool can be used to create NHD events for state, tribal, and EPA programs. It was developed by the Bureau of Land Management (BLM) with input from EPA and USGS. The HEM tool and associated documentation are available for download from: http://nhd.usgs.gov/tools.html Exit


EPA encourages states and tribes interested in using the HEM tool for georeferencing EPA program data to download the tool and associated documentation. Building on its extensive experience in working with NHD events to support EPA water programs, EPA is also developing a supplemental set of indexing functions for the HEM. It is anticipated that these EPA Add-On tools will be available in 2010 along with a user guide, fact sheet, tutorial and training sessions.

Note that the HEM tool supersedes the ArcView 3.0 based Reach Indexing Tool (RIT) providing equivalent or improved functionality. We plan to incorporate information on the HEM into this web site replacing existing references to the RIT.

Below is a list of planned enhancements that will be available in future releases of the HEM tool.

  • Standard HEM Tool
    • Usability improvements to the candidate form
    • Ability to edit high resolution NHD events that come with and are managed as part of the NHD (e.g., stream guages and dams)
  • EPA Add-On Tools
    • Create off-NHD or custom events
    • Extract events from different EPA water programs and previous cycle years
    • Find overlapping area events

For additional information, please see this HEM tool factsheet that provides further details on the tool's functionality:
Fact Sheet (2 pp, 289K, About PDF) 

For more information, please contact:

HEM Tool User Support, Training, & Outreach: Amy Wesley-Snider, RTI International, 919-316-3711 or alwesley@rti.org

NHD and NHDPlus Support: Cindy McKay, Horizon Systems Corporation, 703-471-0480 or ldm@horizon-systems.com

NHD and NHDPlus Project Lead: Tommy Dewald, USEPA Office of Water, 202-566-1178 or dewald.tommy@epa.gov



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