drapeau anglais

International restitution symposium


 2017 02 27 09 46 24 invitation V11 nvlle date ANG.docx   Microsoft Word

After working together for several years as part of the Life program "Ecological Continuity"; The Morvan and Ballons des Vosges natural regional Park's now wish to share their experiences with their partners through an international symposium, from 31 May to 2 June 2017, at the Palais des Congrès in Beaune (FRANCE, 21).
 

For centuries, weirs have been built across rivers to use water energy or create fishponds. Thus the rivers are marked by the development of numerous structures which split them and create a break in ecological continuity.

In order to respond to this issue, the regional natural Parks of the Morvan and the Ballons des Vosges have joined together to the Life program "Ecological continuity, watershed management, and associated heritage fauna". With their partners, they now wish to share their experiences through an international symposium on 31 May and 1 and 2 June 2017 in Beaune (FRANCE, 21).

The simplified program is as follows:

Wednesday 31 may

Thursday 1 june

Friday 2 june

9h

Theme 1 (Plenary): What are the impacts of breaking ecological continuity on the aquatic ecosystem?

Theme 3 (Plenary): How ecologically and sociologically acceptable restoration projects of ecological continuity can be carried out?

Field visits

Theme 2 (Plenary and workshops): What tools or animation techniques can be used to explain ecological continuity?

Collective synthesis of workshops

Theme 4: Which tools of animation of territory make it possible to initiate or perpetuate the actions of restoration of the ecological continuity?

Workshops : ecological continuity, small hydropower, heritage and landscape.

18h

Conclusion, round table and closing of the symposium

The fragmentation of natural environments affects all ecosystem balances. The obstacles present on rivers induce disturbances varying according to their height, their location and the cumulative effect of their succession.

Theme 1 (Plenary session): What are the impacts of the break in ecological continuity on the aquatic ecosystem? Examples of scientific work in France and on an international scale. How can these impacts be quantified before and after work? Apart from improving the aquatic ecosystem, what are the other expected benefits of restoring ecological continuity (resilience to climate change, etc.)?

The restoration of ecological continuity on watercourses is now a major issue in the European Water Framework Directive (WFD) and its declensions in french laws. However, these new regulations are difficult to implement. The historical, landscape and cultural heritage of the weirs are the main reasons for this. Moreover, the evolution of technologies and the development of renewable energies stand up for reflection on small hydroelectricity. To this day, the restoration of ecological continuity is at the heart of the debate and raises a lot of concerns from the riverside owners, elected officials and other users of our rivers.

Workshops (and collective synthesis of workshops):

- Ecological continuity and small hydroelectricity: Is profitability the aim sought-after a property owner? From what production threshold can we say that hydroelectric production becomes of general interest? What is the balance between the level of ambition of restoring ecological continuity and maintaining the hydro-energy potential?

- Ecological continuity and historical heritage: Which elements make it possible to qualify a threshold of historical heritage? Does the loss of the body of water generated by a weirs devalue the built heritage? What is the balance between the level of ambition to restore ecological continuity and the preservation of the historical heritage?

- Ecological continuity and landscape: Which factors determine our preference between a water body and a current river? Are weirs a determining factor in our landscape? What is the balance between the level of ambition to restore ecological continuity and the maintenance of the landscape?

Accompanying this evolution appears as a central and long-term communication issue. It should also be pointed out that this notion of a break in ecological continuity is very complex : it brings together many ecological concepts of watercourses. A better understanding of these mechanisms by the general public and a deeper appropriation of problems of loss of biodiversity will undoubtedly favor a better way of dialogue.

Theme 2: Which methods, tools or techniques of animation are most effective to explain the notion of ecological continuity? Which audience should be targeted? How can academic program be linked to the notion of ecological continuity?

This public policy cannot therefore be reduced to the technical dimension alone. They also have philosophical, sociological and political dimensions. Since the implementation of these directives, several examples of restoration exist. It is possible to propose environmentally and sociologically acceptable solutions. We must rely on functional examples  in France and abroad.

Theme 3: What are the psychosocial restraints to the restoration of ecological continuity? Concrete examples of restoration of ecological continuity, taking into account the heritage, landscape and economic stakes, in France and abroad.

The question of the relationship between man and nature is therefore at the heart of the debate and the subject of water policies. Given the difficulties in implementing policies to restore ecological continuity, improvements should be considered to optimize the implementation of plans and programs.

Theme 4: What is the state of progress of the policy of restoration of ecological continuity in France? How are these policies dealt with abroad? What are the inputs of water policy (GEMAPI, SAGE, TVB ...)? How to develop links between actors?

We therefore hope that this symposium will summarize the issues related to ecological continuity, the difficulties of implementation and the levers for the success of the projects. To know, to reconcile, to act and to communicate, is the method that has been used in the Life program "ecological continuity" and we also want to share it through field visits. Several weirs of mills with different levels of ambitions and stakes will be visited. The constraints related to each sites will be exposed. A pedagogical trail incorporating an interactive model will close the field visits.

 

* The symposium will be translated simultaneously into French and English.

 


See you in March for registration!

If you think you can enrich the discussions, which will take place during the symposium, with a poster and / or oral presentation (scientific studies, concrete case studies, or pedagogical documents), please fill in this form 31 March)

 

 

 Clémence WECK

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03.86.78.79.85

 

 

 

Le moulin Cadoux est inscrit au patrimoine pittoresque de l’Yonne depuis le 19.03.1964.

L’inscription est une reconnaissance de la valeur patrimoniale du site justifiant la surveillance de son évolution et a engendré la consultation de l’Architecte des Bâtiments de France avant travaux.

Bien qu’aucun usage économique n’y soit attaché à ce jour, le complexe hydraulique conserve l’intégralité de ses ouvrages dont un seuil déversant transversal maçonné d’une longueur initiale de 70 m et d’hauteur de chute de 1.7 m (majorité de la crête) à 1.3 m (en rive gauche). Les possibilités de franchissement du seuil du Moulin Cadoux par les poissons étaient très limitées, quelle que soit l’espèce et la taille des individus. Pourtant les enjeux écologiques sont conséquents car la vallée du Cousin est aussi dotée d’une richesse faunistique  très importante avec notamment la présence de la moule perlière qui ne survit que grâce à la présence abondante de tuite fario, son espèce hôte.

De plus, le Cousin est classé en liste 1 et 2, au titre de l’article L.214-17 du Code de l’environnement par les arrêtés de classement des cours d’eau signés le 4 décembre 2012 par le Préfet coordonnateur de bassin Seine-Normandie et publiés au journal officiel le 18 décembre 2012. Compte tenu du classement du Cousin en liste 2, les propriétaires avait une obligation de mise en conformité de leur ouvrage dans un délai de 5 ans après publication des listes.

C’est pourquoi, le Parc naturel régional du Morvan a souhaité apporter son aide en trouvant le meilleur compromis entre la sauvegarde du patrimoine historique, la préservation patrimoine naturel et les obligations réglementaires des propriétaires. Grâce au programme Life, il a pu financer les études (IRH) et les travaux suivant (ROSA).

La passe mise en œuvre est une passe de type « naturelle », constituée d’une rampe inclinée en génie civil, tapissée de blocs en enrochements uniformément répartis.

Le coursier est incliné selon l’axe transversal de manière à éviter la concentration des écoulements dans la partie aval. Cette configuration permet également de présenter une hauteur d’eau variable au sein de la rampe et de diversifier les conditions de passages au regard de la ligne d’eau amont.

L’objectif de ce dispositif est de recréer de manière plus ou moins proche les caractéristiques des cours d’eau naturels à forte pente, en mettant en œuvre une pente relativement prononcée et en intégrant des matériaux naturels (blocs en enrochement) pour la dissipation d’énergie et la réduction des vitesses.

Ce projet de rampe intégrant une partie basse et une partie haute de coursier, permet ainsi de diversifier les conditions hydrauliques dans l’aménagement (débits, vitesses, puissance dissipée), de manière à présenter des conditions de franchissabilité relativement adaptées à l’ensemble des espèces du Cousin selon les conditions d’alimentation.

Dans l’objectif de limiter l’emprise de la rampe en terme de longueur tout en assurant sa fonctionnalité, un arasement partiel et progressif du seuil de – 40 cm a été réalisé sur une dizaine de mètres à partir de la rive gauche. Le miroir d’eau est donc maintenu mais son emprise sera réduite au moment des jours les plus secs de l’été.

Puis un seuil avec échancrure a été mis en œuvre, en aval de la passe à poissons, jusqu’au fond du lit de la rivière, calé de manière  à créer une fosse de dissipation et d'assurer une hauteur d'eau suffisante en pied de rampe.

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