Ecological continuity

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Ecological continuity

Rehabilitation of ecological continuity: Blaise in Dommartin le Franc, la Pissancelle and upstream le Rongeant.

Projet : 

Works for the restoration of ecological continuity form part of the general target objective of a good environmental status for freshwater environments fixed by the European Water Framework Directive. Within this framework, they must, in particular, contribute to restoring the ecological continuity of a body of water which is currently partitioned, as well as avoiding the risk of the rupture of dilapidated hydraulic structures.

 

These two projects, one on the Blaise river, the other on the Rongeant and its tributary, the Pissancelle, were selected because of their ambition, within the framework of a competition for ecological rehabilitation projects initiated by the Seine-Normandy Water Agency. These two projects are financially supported because they are two out of the ten workshop-sites in the basin area.

 

In collaboration with the Chamber of Agriculture, consultations were held with local owners. The cost of the works is approximately two million euros (ex VAT).

 

The works on the Blaise river consist of removing the Varennes structure, the partial filling of the minor river bed, the development of benches alternately on the left and right sides of the river, the locking of the long side profile by installing bottom sills, whilst maintaining the current river track, the river banks and existing streams.

 

Additional works are also planned: security thresholds, downstream ramp.

 

Works on the Rongeant river consist of removing the structures in place, the partial filling of the minor river bed, the development of benches alternately on the left and right sides of the river, the locking of the long side profile by installing bottom sills, refilling of part of the old river bed, the remeandering of the Pissancelle river at the bottom of the valley by creating a new river bed when the current one is not at the bottom of the valley and by partially refilling the river bed when it is in the valley.

Mission : 
  • Morphodynamic survey including hydrological, sedimentary and hydraulic analyses
  • Calculation and mapping of floods for different flows and according to different development scenarios
  • Comparison of four development scenarios based on environmental and financial criteria and with consideration for different uses
  • Sizing of the selected project, material prescriptions
  • Preliminary and project drawings and the preparation of tender documents
  • Assistance with company choices
  • Authorisation
Le projet
Pays/région : 
France
Client: 
Syndicat Intercommunal d’Aménagement de la Blaise - Syndicat Marne Vallage
Période : 
2010-2012
Partenaires : 
ITG
Sialis