GSSHA accounts for the following conditions that may be encountered when simulating watershed hydrology:
- Spatial variability of soil textures, land use, and vegetation that may affect parameter values needed to simulate important hydrologic processes.
- Spatial and temporal variability of precipitation.
- Snowfall accumulation and melting.
- Drainage network of arbitrary shape and cross sections.
- Effect of soil moisture on infiltration and runoff.
- Effect of water table on soil moisture, infiltration, and runoff.
- Gaining and losing streams.
- Hortonian runoff.
- Saturated source areas.
- Wetland peat hydraulics.
- Lake storage and routing.
It has been verified that GSSHA, and/or the methods taken from CASC2D and employed in GSSHA, can be used to simulate the following types of hydrologic variables:
- Stream discharge in Hortonian basins (Doe and Saghafian 1992; Ogden et al. 2000; Senarath et al. 2000; Downer et al. 2002a)
- Stream discharge in non-Hortonian and mixed runoff basins. (Downer 2002; Downer et al. 2002b)
- Soil moistures in Hortonian basins. (Downer 2002).
- Sediment discharge in Hortonian basins (Johnson 1997)