OpenFlows FLOOD uses fully spatially-distributed numerical models to simulate all hydrological and hydraulic processes that occur in river basins, including rainfall, infiltration, surface runoff, channel flow, and groundwater flow. In urban areas, OpenFlows FLOOD can be connected to a model generated by OpenFlows SewerGEMS to simulate the surface and stormwater flow. Additionally, the model can be used to simulate flooding in coastal areas due to storm surges.