Case study:Bocq river (Walphy - LIFE project)
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- 1 Project overview
- 2 Image gallery
- 3 Catchment and subcatchment
- 4 Site
- 5 Project background
- 6 Reasons for river restoration
- 7 Measures
- 8 Monitoring
- 9 Additional documents and videos
- 10 Additional links and references
- 11 Supplementary Information
|Project web site||http://walphy.be|
|Themes||Habitat and biodiversity, Hydromorphology, Monitoring|
|Main contact forename||Alexandre|
|Main contact surname||Peeters|
|Main contact user ID||User:AlexBE|
|Contact organisation||Service Public de Wallonie (SPW)|
|Contact organisation web site||http://walphy.be|
|Partner organisations||University of Liege, University of Namur|
| This is a parent project
encompassing the following
|Eau Blanche River (Walphy - LIFE project)|
In the context of fulfilling the Water Framework Directive requirements, the LIFE+ project Walphy allowed experimental restoration projects to be undertaken on two medium-size catchments of the Meuse basin in Wallonia (Belgium) between 2009 and 2014: the Bocq catchment and the Eau Blanche Catchment. This five-year long project was funded by the European Union and the Service Public de Wallonie (SPW). It involved three institutions: the SPW was in charge of the experimental restoration projects while the Universities of Liège and Namur were responsible for evaluating the success of the restoration projects.
The Bocq is a medium-size gravel-bed river which has been strongly impacted by numerous barriers, impeding the free movement of fish and bedload (an average of one weir every 1.8 km). In addition, some river reaches have been straightened over the last few centuries, which has led to significant loss of habitat.
A multi-scale assessment of hydromorphological conditions of the Bocq catchment has led to a large-scale restoration project implemented mainly in the lower and middle course of the Bocq River itself. 22 barriers (mainly old weirs of an average height of 1.35 m) have been removed or modified in order to reconnect the Bocq with the Meuse and to improve access to areas of spawning grounds. To date, only two barriers remain in the middle Bocq. In addition, 3.6 km of modified reaches were improved through a wide range of rehabilitation techniques such as designing sinuous channels, re-instating spawning grounds, improving fish shelters, improving culvert bed, etc.
Monitoring surveys and results
The success of the restoration projects was evaluated on the basis of a multi-disciplinary monitoring.
Hydromorphology was evaluated on five restored sites using microhabitat survey and three indices of physical quality. For all sites, hydromorphology was significantly improved 10-20 months post-rehabilitation, through the diversification of flows (depth, substrate, water velocity) and the creation of habitats (e.g. fish shelters, spawning areas and woody debris).
Biological quality, based on macroinvertebrates and fish communities, has generally showed a status quo or a slight increase 10-20 months post-completion. Nevertheless, ambitious rehabilitation measures such as weir removal and meanders restoration have resulted in the most positive effects, while less ambitious measures such as habitat diversification have led to more contrasted results. In addition, restoration of the longitudinal connectivity was beneficial for Grayling, designated as Natura 2000 species, and for eels, concerned with the Benelux convention.
The geomorphological monitoring has focused on the effect of barriers on sediment transport and the effectiveness of spawning gravel rehabilitation.
- Despite the short period of time (5 years) of this project, we realized afterwards the importance of achieving a multi-scale assessment and an initial state (pre-restoration) prior to restoration work.
- We implemented a wide range of demonstration techniques and we compared them in terms of cost-effectiveness (see the Manual of River Restoration Techniques on http://www.walphy.be/index.php?page=guide-technique).
- Most of the restoration projects could be implemented without acquiring the land but rather through negociations with the local community. This underlines the importance of engaging the local community.
- The time span of the project allowed us only 1-2 years of monitoring (post-restoration). Fortunately, the SPW funded a long-term monitoring (>3 years), which is crucial for accurate evaluation of success, especially for biological indicators.
- Finally, we hope the project to give a boost to future restoration projets in Wallonia.
Catchment and subcatchment
Select a catchment/subcatchment
Cost for project phases
Reasons for river restoration
Hydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Additional documents and videos