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WALPHY - Design of a decision tool for hydromorphological restoration of water bodies in Walloon Region

LIFE07 ENV/B/000038


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Contact details:

Project Manager: Francis LAMBOT
Tel: +32 081 336359
Fax: +32 081 336335
Email: francis.lambot@spw.wallonie.be



Project description:

Background

The biological recovery of a river is dependent of the recovery of its structure and its physical dynamics. Returning a river to "good ecological status" inevitably involves its physical restoration, given that its physical characteristics affect its functioning.

Three types of modification are key obstacles for good ecological status:

  • Alteration of the flow (discharge and sedimentation);
  • Alteration of form;
  • Biotope access alteration (lateral connections breaks, modification of the continuity upstream/downstream, etc.).
  • Taking into account a river’s hydromorphology is needed to implement the Water Framework Directive (WFD) as well as the Flood Directive (2007/60). So far, stakeholders have improved hydromorphological quality without knowing exactly the consequences of their actions: the impact of a dam removal or water course section remeandering, for example. They usually get very little feedback (post-work is usually short-term) on the benefits of restoration of water quality and ecological status. Modifying or ‘manipulating’ ecosystems requires expert knowledge of watercourse dynamic mechanisms.

    Hydromorphological quality improvements can be measured by changes in physical or chemical parameters of the environment but also by changes in the composition and structure of plant and animal communities (which depend on the aquatic environment). The identification of mechanisms or natural processes that would ensure the sustainability of improvements is needed, in order to improve the restoration approaches, but also because the natural environment is variable. For instance, the effects of climate change, such as an increase in the flood frequency and intensity, has to be taken into account.


    Objectives

    The WALPHY project planned to pilot a structured approach to improving the hydromorphological quality of the River Meuse basin in Wallonia, in order to reach the "good ecological status" required by the Water Framework Directive (WFD).

    The specific objectives of the project were to:

    • Develop of a methodology for helping to define the restoration works to be undertaken to improve the hydromorphological quality of water bodies "at risk";
    • Carry out restoration works on a significant scale on some water bodies at risk of not reaching the good status, based on two axes: longitudinal continuity and transverse continuity (area of freedom);
    • Monitor the restored river system and its ecological status evolution at the local level (site of intervention) and the scale of the whole water body;
    • Refine the methodology for the development of technical guidelines (decision-making tools) for river stakeholders, in line with the implementation of the WFD; and
    • Disseminate these tools and recommendations to the authorities, stakeholders and the public.


    Results

    The WALPHY project achieved its aim of developing a methodology for assessing the hydromorphological river quality.

    The selection of the water bodies to be restored was based on the score obtained in the ecological evaluation. An additional three water bodies were selected owing to the significant alterations that had carried out on these sites. A preparatory assessment was carried out by adapting and improving an existing tool known as Qualphy (Qualphy stands for Qualité Physique) for estimating the physical status of rivers. The selection of the water sheds to be managed was thus carried out using the improved Qualphy method The selected water bodies were the Bocq aval (Bocq downstream, MM30R), the Bocq amont (Bocq upstream, MM28R) and a part of the Eau Blanche aval (Eau Blanche downstream, MM05R).

    The preparatory assessment using the improved Qualphy method showed that the transversal connectivity on the Bocq was not that bad, while the longitudinal connectivity was disrupted by numerous obstacles that are difficult or impossible for fish to cross. The team also found that the longitudinal connectivity on the Eau Blanche was acceptable but that the transversal connectivity (the natural connections between the river and the alluvial plain) was very poor. Indeed the Eau Blanche has been heavily affected by works carried out in the middle of the last century. As a result, the project focused on the restoration of the longitudinal connectivity on the Bocq through the removal/management of obstacles and on the restoration of lateral continuity on the Eau Blanche.

    In total, the project was able to remove 20 obstacles for fish migration (19 on the Bocq and one on the Eau Blanche). In some cases the obstacles were destroyed (e.g. the demolition of a dam). However, in many cases such action was not possible. Some dam owners did not consent because they have or are planning to construct mini hydroelectric power plants. In other cases, the role of the dam is important in relation to bridges and other constructions. In those cases, other solutions were implemented solely or in combination, including the creation of river bypasses, pre-damns, fish ladders etc. At the site of Vivaqua, where the river Bocq transforms into a concrete canal, it was not possible to establish a bypass river. Instead blocks of stone of various sizes were fixed on the concrete bottom.

    Furthermore, the transversal continuity/connectivity of around a 22 km-stretch of river was improved. Different kinds of techniques were implemented. In several locations the works were limited to the river bed with small-scale meandering. Also, various structures were put in place to diversify the habitat. In other areas, more ambitious works were implemented such as the restoration of a former meander on the Eau Blanche and on the Leignon. A former side river of the Eau Blanche Plain (the Grand Morbi) was reopened and reconnected with the Eau Blanche.

    The monitoring showed that the removal/management of obstacles is an effective way to improve fish mobility and population size. Furthermore, the removal of obstacles helps improve the transport of the bottom charge (sediments), resulting in higher quality gravel banks as spawning places. The monitoring showed also that the less ambitious works in the river bed are much less effective than the ambitious remeandering and reconnection of side rivulets. Continued action as outlined in the After LIFE Communication and Conservation Plan is already benefitting from lessons learned during this monitoring stage.

    Finally, the beneficiaries organised a final scientific conference, which attracted 210 attendees, including around 80 from outside Belgium. The results of the project were further communicated by the erection of information panels at the sites and the production of teaching materials. The project also produced a film detailing the restoration techniques developed and implemented by the project. A well-designed technical guide in French was produced.

    Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).


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Environmental issues addressed:

Themes

Risk management - Site rehabilitation - Decontamination
Water - River basin management


Keywords

decision making support‚  hydrographic basin‚  restoration measure‚  river management


Natura 2000 sites

Not applicable


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Beneficiaries:

Coordinator Service Public de Wallonie
Type of organisation Regional authority
Description SPW-DGO3 (Service Public de Wallonie, Direction générale opérationnelle Agriculture, Ressources naturelles et Environnement) is one of eight directorates-general that make up the Ministry of the Walloon Region. The project beneficiary is the non-navigable rivers unit (Direction des Cours d’eau non navigables) within SPW-DGO3.
Partners Université de Liège-Laboratoire d'Hydrographie et de Géomorphologie Fluviatile, Belgium Facultés Universitaires ND de la Paix Namur (FUNDP)-Unité de Recherches en Biologie des Organismes, Belgium

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Project reference LIFE07 ENV/B/000038
Duration 01-JAN-2009 to 31-DEC -2013
Total budget 2,861,641.00 €
EU contribution 919,161.00 €
Project location Région Wallonne(België - Belgique)

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Read more:

Brochure "Watercourse rehabilitation : complementarity between morphology and water quality" (480KB)
Leaflet "Pour répondre à la Directive cadre eau: Walphy, u ...
Poster Project Poster (526KB)
Project web site Project's website (FR)
Publication "Réhabilitation hydromorphologique des cours d'eau ...
Publication: After-LIFE Communication Plan Plan de Communication After-LIFE
Publication: Guidelines-Manual "Conception d’un outil d’aide à la décision pour l ...
Publication: Guidelines-Manual "La restauration hydromorphologique des cours d’ea ...
Publication: Guidelines-Manual "Techniques végétales: Conception, application et ...
Publication: Layman report Rapport layman
Publication: Proceedings "La restauration hydromorphologique des cours d’ea ...
Publication: Research findings Title: "Walphy, un projet expérimental de réhabilitation de cours d’eau : suivis hydromorphologiques et écologiques" (http://www.hydroecologie.org/articles/hydro/pdf/first/hydro150014.pdf) Author: CASTELAIN L., PEETERS A., HALLEUX M., et al. Year: 2016 Editor: EDF No of pages: 27
Publication: Technical report "Conception d’un outil d’aide à la décision pour l ...
Publication: Technical report Project's Final technical report
Video link "Images in, octobre 2010" (26')
Video link "Rivières, le retour à la continuité écologique: Un projet de restauration en Wallonie" (30')

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Project description   Environmental issues   Beneficiaries   Administrative data   Read more   Print   PDF version