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

The lower course 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 barrage on the Rhine. After severe flood damage in the 1980s, the affected municipalities founded the special-purpose flood protection association, which is responsible for the implementation of a regional flood protection concept developed by the water management administration and consisting of 16 measures.

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 development of the watercourse bed created in the 1970s. The dike was only to be relocated by approx. 20 m to create an additional discharge profile.

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

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

Dead and living wood in the midwater bed are the essential structural elements.

But on almost all streams, wood in the stream bed conflicts with flood control and usually must be completely removed as part of maintenance.

On the Schutter River, flood control was provided by using the previous, developed bed as a flood channel. The meandering watercourse bed, which was recreated on the basis of a historical model elsewhere, is therefore largely free of drainage and maintenance constraints and is left to its own dynamics. Maintenance is concentrated on the flood channel, which is only flowed through during floods when the capacity of the new near-natural stretch of water is exceeded. By installing all the woody plants to be removed in the course of the measure in the area of the new stream course, an "initial equipment" of the watercourse with riparian woody plants and deadwood was specified.

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.