To download HEC-GeoHMS for ArcGIS 10.8, you can use the official Esri download directory specifically for this version. This extension allows you to prepare GIS data for hydrologic modeling directly within the ArcMap 10.8 environment. Download and Installation Details
Calculation of physical basin characteristics (area, slope, flow path length). download hec geohms for arcgis 108 exclusive
Prerequisite: You must have Arc Hydro Tools for ArcGIS 10.8 installed before installing HEC-GeoHMS. To download HEC-GeoHMS for ArcGIS 10
This usually means the Spatial Analyst extension is not enabled. Go to Customize > Extensions and check the box. If the box is checked but the tool is still inactive, verify your ArcGIS license level (Basic, Standard, or Advanced). Component Category Manager Errors To download HEC-GeoHMS for ArcGIS 10.8