Flood protection and near-natural transformation of the Schutter estuary near Kehl

The lower reaches of the Schutter and its mouth into the Kinzig were relocated and technically upgraded in the 1970s in connection with the construction of the Freistett Rhine barrage. After severe flood damage in the 1980s, the affected municipalities founded the special purpose association for flood protection, which is responsible for implementing a regional flood protection concept consisting of 16 measures developed by the water management administration.

The flood protection concept, for which a regional planning procedure had been carried out, provided for an increase in the capacity of the Schutter estuary (measure 13/14) through the near-natural expansion of the river bed created in the 1970s. The dyke was only planned to be moved back by approx. 20 m to create an additional drainage profile.



In the course of the accompanying landscape conservation planning, the concept was modified on the basis of models for lowland floodplain streams that had been developed in the meantime and integrated into the planning:



In lowland floodplain streams, the 1 to 3-year flood flows outside the constantly dynamically changing, meandering watercourse bed in the floodplain under natural conditions.



Dead and living woody plants in the middle water bed are the main structural elements.



On almost all streams, however, wood in the riverbed conflicts with flood protection and usually has to be completely removed as part of maintenance.



On the Schutter, flood protection was ensured by using the previously developed bed as a flood channel. The meandering riverbed, which was newly created elsewhere based on the historical model, is therefore largely free of discharge and maintenance constraints and is left to its own dynamics. Maintenance is concentrated on the flood channel, which is only crossed when the capacity of the new near-natural watercourse section is exceeded during floods. The installation of all the trees and shrubs to be removed in the course of the project in the area of the new course of the stream has resulted in the watercourse being "initially equipped" with riparian trees and deadwood.

AppreciationGerman Landscape Architecture Award 2003

Jury verdict: At the latest after the Elbe floods in 2002, it became clear that river engineering measures in the past followed too strongly technocratic specifications. The Schutter estuary project impressively demonstrates how the original floodplain landscape with its meandering streams can be restored through renaturation and near-natural deconstruction of the Schutter.

Landscape architectural measures and the shoring up of deadwood reduce the risk of new flood events and lead to the ecology in the river section being restored. In addition, the project proves that viable flood protection concepts can be found through early involvement of landscape architects.