The Hördter Rheinaue case is situated in the Upper Rhine valley in southwest Germany. It encompasses part of the Rhine’s sub-recent floodplain on the left bank of the river. Nowadays a dyke separates the area from the River.
Straightening the course of the River Rhine in the 19th century and constructing barrages in the 20th century to allow the river to be used as a major water way in Western Europe resulted in a great loss of natural retention areas and increased the flood risk. Floods are mainly caused by heavy rainfall and intense snowmelt.
The state of Rhineland-Palatine and other states bordering the river Rhine want to create emergency polders for floods with return intervals > 200 years. In future, the Hördter floodplain will store up to 36 million m3 of water in an area of 870 hectares. This planned measure will ensure a better protection of goods and people.
A public moderation procedure is used in the planning process to assure the involvement of all relevant stakeholders. Existing forest management will be adjusted to flood conditions by implementing ecological flooding. Compensatory measures will be implemented in accordance with environmental legislation.
Renewal historic sluice first step in Hörd floodplain project.
The Hördt floodplain reserve retention area is part of the differentiated system of flood protection in the state of Rhineland-Palatinate in Germany. This area protects the upper Rhine valley between Karlsruhe and Mannheim against inundations higher than a 200 year flood-event return interval.
The first step of the project is the renewal of a historic sluice which leads the Michelsbach, the main stream of the area, into the river Rhine. This project part started in June 2011 and will be finished in 2012.
The Hördt floodplain covers an 870 ha area of wetland forest, meadows and agricultural areas, surrounded by several old branches of the river Rhine. The project includes the strengthening of the existing front dyke and the arrangement of three bars of 300 m length. At the event of an extreme flood, it allows the water to get into the reserve area and into the construction of a new rear warded main dyke with several sluices and pumping stations that should bring the incoming watercourses into the reserve area. The project will be complemented by an ecological flooding system of the former river branches by constructing three passages, which let Rhine water into the deepest spaces of the area. The capacity of the reserve retention area is nearly 36 million cubic meters, the total costs will amount up to 57 million euro.< What How >
Planned measures in Hördter Rheinaue area:
- Reinforcement of the existing dyke
- Construction of a new main dyke at some distance from the river Rhine
- Construction of two new pumping stations and reinforcement of two existing ones
- In case of polder operation mobile systems for pumping will be used too
- Construction of three apertures in the existing dyke to allow ecological flooding
- Construction of three spillways in the existing dyke to allow the inflow of water in case of operation
project by ALFA partner(s):