GeoSWMM Conceptual Model

GeoSWMM conceptualizes a drainage system as a series of water and material flows between several major environmental compartments. These compartments also contain GeoSWMM objects. The Atmosphere compartment, from which precipitation falls and pollutants are deposited onto the land surface compartment. GeoSWMM uses Rain Gage objects to represent rainfall inputs to the system. The Land Surface Compartment, which is represented through one or more Subcatchment objects. It receives precipitation from the Atmospheric compartment in the form of rain or snow; it sends outflow in the form of infiltration to the Groundwater compartment as surface runoff and pollutant loadings to the Transport compartment. The Groundwater compartment receives infiltration from the Land Surface compartment and transfers a portion of this inflow to the Transport compartment. This compartment is modeled using Aquifer objects. The Transport compartment contains a network of conveyance elements (channels, pipes, pumps, and regulators) and storage/treatment units that transport water to outfalls or to treatment facilities. Inflows to this compartment can come from surface runoff, groundwater interflow, sanitary dry weather flow, or from user-defined hydrographs. The components of the Transport compartment are modeled with Node and Link objects.

Not all compartments need to appear in a particular GeoSWMM model. For example, one could model just the transport compartment, using pre-defined hydrographs as inputs.