ArcHydro vs HEC-GeoHMS

11-14-2012 07:11 AM
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New Contributor
Who is the main developer for ArcHydro? Ive found the HEC-GeoHSM watershed processing algorithms are the exact same as arcHydro. As Im sure this is no coincidence, which came first? Does ACoE control/oversee development of both?

Thanks for your help. Im working an uncertainty analysis report that is investigating the differences between terrain processing methods/options in ArcGIS. Any extra information you may have (eg lists of hydro extensions, documentation of background algorithms, etc would be extremely helpful)

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Occasional Contributor III
My understanding from my GeoHMS training via ESRI is that ESRI is the developer of both. The Corps (HEC - Hydraulic Engineering Center hired ESRI to develop HEC-GeoHMS and HEC-GeoRAS.

At times, I understand (and I could be off here) there can be a lag between the latest ArcHydro (ESRI controlled release) and HEC-GeoHMS (Corps controlled release). This is because HEC staff does a thorough review of the product before they release it internally. This could explain why it takes a while for a versions of the HEC products to catch up with a new version of ArcMap.

My understanding (and I could be off here too) is the the Corp uses and supports the HEC products in-house. They do not provide software support to general public (their documentation is usually darned good and suffices for my purposes). That is why there are companies/consultants that provide training on the HEC products instead of HEC itself. The HEC products are posted on-line because they are government funded and therefore public domain.

Again. This is just my understanding of the situation.
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MVP Frequent Contributor
I do not believe that the HEC programs are in any sense required to be posted to the Esri maintained ftp server, rather they are placed there as a courtesy for access by the broader Surface Hydrology community (beyond the USACoE and HEC users).

ArcHydro is collaboratively developed by Esri, govenmental, academic and commercial users.  It has a much broader user base than the HEC goespatial preprocessor programs, and as a result is more actively developed.

The only thing to add to Mark's comments is that Hydrologists requiring technical and integration support beyond what the community can provide are able to contract with Esri's Professional Services -- Water Resources Group for needed technical support.

You can reach them at:, or via phone contact Dean Djokic, at 909-793-2853, extension 1-1072. If you are outside the United States, contact the Esri office that serves you.

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New Contributor
Delayed, but thanks so much for your replies! Great insight and appreciate the contact info
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