FEM-Floodplain Evaluation Matrix as tool to assess the role of floodplains for reducing flood risk

Due to economic pressure, increasing population and spatial demands for living space floodplains are progressively lost over time. This summation effect leads to a downstream acceleration and increase of flood waves and related flood risk. In order to assess the role of floodplains for reducing flood risk the Floodplain Evaluation Matrix FEM allows a quantification of changes of related river floods. FEM combines hydrological and hydraulic parameters. The hydrological parameters flood peak reduction and flood wave translation demonstrate regional floodplain effects. Local hydraulic parameters are water surface level, flow velocity or shear stress. This paper discusses the basic concept of FEM and demonstrates its potential by applying it to river case studies of different size, land use and flood risk boundary conditions.