Precipitation runoff models
River basin models
The precipitation-runoff behaviour of catchment areas is often of interest in flood protection issues. The individual catchment area (sub-area), whose characteristics are derived from soil use, soil types, development share, gradient, land use, is responsible for the lateral inflow along waters and is mapped with an N-A model. The unit and discharge hydrographs of a catchment area are calculated according to rain events and area characteristics. Different models are used for this, such as Lutz's.
In a river basin model (FGM) the individual N-A models (subareas) are linked. The FGM consists of several N-A models (hydrographs) which are arranged along a stretch of water and flow into the FGM. A detailed mathematical model for the determination of a discharge hydrograph from the entire catchment area is generated. As in the N-A calculation, different models are used for the wave deformation along the stretch of water. The simulation of dams is carried out, for example, by means of sea retention.
The models are used to determine flood runoff along watercourses and to design flood protection facilities such as retention basins. The models can also be used to simulate the influence of planned buildings.