Volume conservation is carefully tracked and is reported both during the simulation and in output files. The channel width can be larger than the grid element allowing for more detailed floodplain simulations. When the flow in the channel exceeds the bank height, an interactive routine in FLO-2D will compute the overbank discharge. This channel-floodplain flow interaction can occur in both directions with overland return flow to the channel. With urban flooding, the model can simulate channel overbank flow through neighborhoods , down streets and then have return flow to the channel at a downstream location.
Tributary inflow is unlimited.
Rainfall and Infiltration Rainfall can be simulated on the potential flow surface before or during the flood simulation. The rainfall is then routed as overland sheet flow or as rill and gully flow until it intercepts a main channel. Infiltration is simulated with the Green-Ampt infiltration model and can be spatially variable on the flow surface. Street, Bridge and Culvert Flow Street discharge is simulated as flow in a shallow rectangular channel. Streets may intersect and are delineated with a width and curb height.