You can also browse the Arc Hydro Setup Repository to find the folder corresponding to "10.8".
Ensure you select the build specifically designed for ArcGIS 10.8 (e.g., folder 10.8.x). Versions for ArcGIS Pro and different ArcMap releases are separate and must match your installed ArcGIS Desktop version exactly. Key Features for Version 10.8 Arc Hydro GIS for Water Resources - Esri arc hydro tools 10.8 download
Arc Hydro Tools is a specialized GIS extension developed by Esri and its partners to support water resources applications. It provides a standardized data model and a comprehensive set of tools for hydrological analysis, including watershed delineation, stream network generation, and rainfall-runoff modeling. You can also browse the Arc Hydro Setup
To download Arc Hydro for ArcGIS 10.8, you must access the official Esri Water Resources download portal. Arc Hydro is free for users with a valid ArcGIS software license. Arc Hydro Tools Downloads - Esri . Key Features for Version 10