Floods Glossary

retention area

Areas of land along bodies of water that by nature are covered with water during a flood and therefore contribute towards retention. The construction of dykes along the entire length of many rivers and brooks has made many of these retention areas ineffective. The water stays in the river or brook and the flood situation is made worse downstream. Nowadays attempts are being made to reactivate these areas by restoring them to their natural state, thus making a contribution towards flood protection. All the same, this can only be meaningful effort if natural retention is permitted on a long scale, which is almost impossible in many areas on account of the present land use. Isolated local measures are practically useless in terms of the lowering of the flood crest, because - if there is no control - the areas are already inundated as the flood wave rises so that there is little further when the crest is reached.