Assessing hydropower potential is particularly challenging, as the flow in rivers is affected not only by the weather, but by how the land surface and subsurface stores and releases water. 3TIER’s hydro assessment systems are based on physical modeling techniques that can integrate available observations while retaining the ability to work independently of observations. These systems are valuable for assessing hydropower potential in remote regions — particularly for run of river and kinetic hydropower — and in areas where observational datasets are absent. Additionally, 3TIER can utilize these same modeling approaches to provide valuable guidance on the possible impacts of land use change and global climate change on a hydropower project’s most important asset — the watershed that provides its water.