Appendix-A: Storm Network Representation in GeoSWMM

GeoSWMM models a conveyance network as a series of nodes connected by links (Figure 2.1). Links control the rate of flow from one node to the next and are typically conduits (e.g. open channels or pipes) but can also be orifices, weirs, or pumps. Nodes define the elevation of the drainage system, and the time-varying hydraulic head applied at the end of each link it connects. The flow conveyed through the links and nodes of the model is ultimately discharged to a final node called the outfall. Outfalls can be subjected to alternative hydraulic boundary conditions (e.g. free discharge, fixed water surface, time varying water surface, etc.) when modeled with Dynamic Wave.

All hydraulic elements modeled in SWMM are classified as either nodes or links. The hierarchy of these elements is shown below along with both the required and optional properties that characterize each element’s hydraulic behavior.