Technology for coping with floods in the 21st century

Abstract

The state-of-the-art of measures and technology for coping with floods at the end of 20th century is a prerequisite for developing better ways of coping with them in the 21st century. Four groups of measures for coping with floods are: do-nothing, non-structural, structural, and a mixture of structural and non-structural measures. The do-nothing alternative means learning to live with floods. Flood impacts are minimized by avoiding them. Non-structural measures are of three categories: regulation for proofing of flood plains (zoning, coding), defense from floods, and flood insurance. Structural measures are divided in (area-, space-) extensive and (point-, line-) intensive measures. The extensive structural measures include reshaping of land surface, soil conservation, flow delay, and increase of infiltration. The intensive measures consist of four categories: levees and dikes, water storage, increase of channel flood capacity, and flood plain polders and platforms. Increase or exclusion of storage space, as intensive structural measures, highly affect floods. Mixtures of structural and non-structural measures may often turn out to be the economically most attractive way of coping with floods. The future of the do-nothing alternative on floods will highly depend on the concepts of how and to what degree the environment is to be protected. The future of non-structural measures will require implementation and discipline rather than new technologies. Extensive measures may be unavoidable because of required conservation of soil, efficient management of land use and protection of the environment. A combination of structural and non-structural measures may include only extensive structural measures, if protection of the environment excludes intensive structural measures for any valid reason.