Case study:Restoration of the Erft-river in Weilerswist
This case study is pending approval by a RiverWiki administrator.
Project overview
Status | Complete |
---|---|
Project web site | |
Themes | Economic aspects, Fisheries, Flood risk management, Habitat and biodiversity, Hydromorphology, Monitoring, Spatial planning, Water quality |
Country | Germany |
Main contact forename | Volker |
Main contact surname | Gimmler |
Main contact user ID | |
Contact organisation | Erftverband |
Contact organisation web site | http://www.erftverband.de/ |
Partner organisations | |
Parent multi-site project | |
This is a parent project encompassing the following projects |
No |
Project summary
The Erft River was heavily trained in the 1960s to provide a higher discharge capacity for flood prevention and to make it easier to mechanically maintain the river. High dams were built along the river banks and the river bed was secured with large rocks. This river training resulted in a river with few structures ans a low morphological diversity.
The restoration project has been implemented in Cooperation of the Landesbetrieb Straßen NRW (the state road authority) and the Erftverband (water board in the Erft watershed) to compensate the impact on nature and environment caused by the construction of a new road. The measure has been necessary to reach the Good Ecological State of the Erft required by the WFD. By adressing the need for compensation with a river improvement measure, inefficiencies in public spending has been avoided.
The project started in April 1995 and aimed at developing a structure-rich, ecologically permeable stretch of the river with regularly flooded meadows and a high potential for self-development. About 10 hectares of cropland were bought and turned into a meadow on the left hand side of the river, towards the lowest part of the valley. The dam along the Erft separating this meadow from the river has been removed. The rocks securing the river bed on that side have been removed and groynes have been built in the river bed to add morphological diversity and initiate lateral erosion. The groynes have been designed in cooperation with the local fishery association, and according to their observation, young fish which have been drifted away by floods in the past are now able to stay in the area.
Monitoring surveys and results
Lessons learnt
Catchment and subcatchment
Site
Name | |
---|---|
WFD water body codes | |
WFD (national) typology | |
WFD water body name | |
Pre-project morphology | |
Reference morphology | |
Desired post project morphology | |
Heavily modified water body | |
National/international site designation | |
Local/regional site designations | |
Protected species present | |
Invasive species present | |
Species of interest | |
Dominant hydrology | |
Dominant substrate | |
River corridor land use | |
Average bankfull channel width category | |
Average bankfull channel width (m) | |
Average bankfull channel depth category | |
Average bankfull channel depth (m) | |
Mean discharge category | |
Mean annual discharge (m3/s) | |
Average channel gradient category | |
Average channel gradient | |
Average unit stream power (W/m2) |
Project background
Reach length directly affected (m) | 100100 m <br />0.1 km <br />10,000 cm <br /> |
---|---|
Project started | 2002/04/01 |
Works started | |
Works completed | |
Project completed | 2009/12/31 |
Total cost category | 500 - 1000 k€ |
Total cost (k€) | 717000717,000 k€ <br />717,000,000 € <br /> |
Benefit to cost ratio | |
Funding sources | Landesbetrieb Straßen NRW (the state road authority) and the Erftverband (water board in the Erft watershed) |
Cost for project phases
Phase | cost category | cost exact (k€) | Lead organisation | Contact forename | Contact surname |
---|---|---|---|---|---|
Investigation and design | |||||
Stakeholder engagement and communication | |||||
Works and works supervision | |||||
Post-project management and maintenance | |||||
Monitoring | 500 - 1000 k€ | 717000717,000 k€ <br />717,000,000 € <br /> | Erft Verband | Volker | Gimmler |
Reasons for river restoration
Measures
Structural measures
| |
---|---|
Bank/bed modifications | |
Floodplain / River corridor | |
Planform / Channel pattern | |
Other | |
Non-structural measures
| |
Management interventions | |
Social measures (incl. engagement) | |
Other |
Monitoring
Hydromorphological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative |
Biological quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative |
Physico-chemical quality elements
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative |
Any other monitoring, e.g. social, economic
Element | When monitored | Type of monitoring | Control site used | Result | ||
---|---|---|---|---|---|---|
Before measures | After measures | Qualitative | Quantitative |
Monitoring documents
Image gallery
Additional documents and videos
Additional links and references
Link | Description |
---|
Supplementary Information
Edit Supplementary Information