The most reliable way to obtain HEC-GeoHMS for ArcGIS 10.8 is through the Esri Downloads Archive.

To successfully run HEC-GeoHMS on ArcGIS 10.8, ensure your system meets these requirements:

: Although the U.S. Army Corps of Engineers (HEC) officially tested and verified versions only up to ArcGIS 10.2, they direct users to Esri for newer versions.

: You must have a valid installation of ArcMap.

: It is highly recommended to install the corresponding version of Arc Hydro Tools for ArcGIS 10.8 first, as GeoHMS often relies on Arc Hydro's underlying data structures. Why Switch to Modern Tools?