Floodplains are natural flood areas along water courses. Rivers and their floodplains form a unit. They belong to the most species-rich, yet most threatened habitats in Europe. Floodplains offer a great variety of mosaic-like interlocked habitats and harbor two thirds of all symbiotic communities in Central Europe on merely about seven percent of the land area. Floodplains are able to assimilate copious amounts of water, thus helping to attenuate flood waves; so the restoration of floodplains is also serves the purpose of flood control. Concurrently, floodplains serve as a river's biological clarification plant: the influx is cleansed more by far than in the river itself. Floodplains help to keep rivers biologically, physically and chemically stable and are the feeding grounds and nurseries of fish and amphibians.
Where floodplains are still natural – along the Loire, for instance - they show their full dynamic: the land-forming force of the river creates and razes backwaters adjacent to the current, high, dry gravel ridges and flat, wet depressions, wide mud banks, buffs devoid of vegetation and dense willow forests. Plant and animal species aplenty have adjusted to these dynamic processes.
As long as there are humans, they will make use of floodplains. Nearly all ancient high cultures in human history originated in floodplains. Only within the past 200 years, large areas of floodplains have been disconnected from the river partially or completely, they have been destroyed and obstructed extensively. Numerous former floodplains have been drained for agricultural use, industry and settlement areas. By straightening the river, building barrages, dikes etc., man has banned the dangers of flooding in some areas, yet in many cases, increased it considerably downstream.
Approximately 130 km² of flood detention areas have been lost along the Upper Rhine since 1955. Furthermore, a flood wave will flow much faster from Basel to Karlsruhe and could overlap with other flood waves from tributary streams. Floodplains are destroyed by other area-based uses such as the harvesting of sand and gravel and unregulated recreational use. Apart from that, intensive forestry takes its toll as well: monotonous poplar plantations oust the hardwood floodplain forests, which are rich in species. As a consequence, many rare avian species, such as the middle-spotted woodpecker and insects such as the great capricorn beetle lose their natural habitat.
In many places, however, floodplains can be revived by restoration programs: unspoiled areas could be reconnected to the river - and thus, to the current's natural dynamics - e.g. by means of deconstructing dikes. Furthermore, reconnecting floodplains to rivers is not only the most environmental friendly form of flood control, but also the most inexpensive form of flood control. The biocenoses of floodplains are not only well-adapted to floods, but demand floods on a more or less regular basis.