SWMM 5 Fixed Surface Water Depth Boundary Condition
Subject: SWMM 5 Fixed Surface Water Depth Boundary Condition A large difference between SWMM 5 and SWMM 4 is how the Groundwater Aquifer interacts with the drainage network. In SWMM 4 since the hydrology was simulated in the Runoff Block , the results saved to an interface file and the hydraulics were simulated in the Extran Block it was not possible to have a time step to time step interaction between the Aquifer and the Open Channels. SWMM 5 has integrated hydrology and hydraulics so it is possible to use either a Fixed Surface Water Depth for each Subcatchment or the Receiving Nodes Node Depth Invert Elevation – the Aquifer Bottom Elevation. The groundwater thus flows either to a fixed boundary condition as in SWMM 4 or to a time varying boundary condition.