Wetlands are unique in their hydrologic characteristics in that they closely couple groundwater flow, surface water flow, and water storage. GSSHA employs a conceptual model that operates on a cell by cell basis.
The model that GSSHA uses allows infiltration and exfiltration, lateral seepage flow, flow through dense vegetation, and flow overtopping the vegetation.
Figure 27. Lateral seepage flow conceptually is the flow through the subsurface peat layer. It is calculated as a darcian flow across the entire cell face. The flow through the vegetation is computed as a mixed mode flow, darcian and manning's. The flow is computed for both darcian and manning's flow and the actual flow rate varies between the two depending on the water height in relation to the plant height.
Figure 28. The flow through the vegetation is treated as fully darcian at the bottom of the vegetation and fully manning's at the top of the vegetation. It varies linearly between the two extremes.
GSSHA Wiki Main Page
Primer Main Page
- Wetlands conceptual model
- Wetlands setup