Water ecological development measure Kettwiger/Mintarder Ruhraue

The Kettwiger/Mintarder Ruhraue is an essential part of a priority area of the EU Water Framework Directive (WFD) identified in the implementation roadmap for the planning unit "Lower Ruhr". As a pilot project for the implementation of the WFD on the Ruhr, a water ecological development measure is to be realised on the state-owned areas within the nature reserve "Untere Kettwiger Ruhraue" and in adjacent watercourse sections of a total length of 2.4 km.

For this purpose, the design and approval planning, the landscape conservation plan, the environmental impact assessment and the species protection report have been prepared since 2011. Based on a monitoring with efficiency control of the nature reserve during the years 2000-2001, which was also carried out by Büro Hahn, a comprehensive inventory was carried out. It also formed a valuable basis for the measures for floodplain development.

The measures for watercourse redesign include the creation of a tributary and a dynamisation of the banks with parallel channels in the area of the forelands, islands, shallow bank sections and break-off edges. The hydromorphological measures to achieve the "good ecological potential" were derived exemplarily on the basis of fish. A digital terrain model was used for the planning, with which, among other things, the soil masses to be moved could be quantified.

The planning was designed on the basis of hydraulic modelling (by ProAqua) and validated within the framework of hydraulic variant calculations. With the 2D model used, it was possible to simulate the flow paths in the tributary and the riparian zones as well as flooding scenarios of the floodplain.

Currently, the detailed design including the tender documents is being prepared. The work is to be carried out partly from the water.