Saâne Valley

© Larrey & Roger / Conservatoire du littoral
© Larrey & Roger / Conservatoire du littoral
© Larrey & Roger / Conservatoire du littoral
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The Saâne Valley, with its small coastal river, is representative of the issues encountered in the lower valleys of the Albâtre coast: coastal erosion, frequency and intensity of storms, flooding.

Site description

The Saâne is a coastal river in the Seine-Maritime department. The SaâneValley is representative of the lower valleys of the Albâtre coast. However, the Saâne foreshore has the peculiarity of being occupied by two separate communities: Sainte-Marguerite and Quiberville-sur-Mer. This administrative division is also reflected in different practices and contrasting landscapes on either side of the valley slopes.

Urbanisation has developed on the western shore of the lower valley, which is sheltered from the prevailing winds. The first developments in the lower valley were sea walls built for protection against attacks by the British. In the 18th century, the fashion for sea bathing saw an increase in accessways onto the beaches, beach huts at the head of the beaches and seafront urbanisation in Quiberville-sur-Mer. The outflow pipe and the seafront road linking Quiberville and Sainte-Marguerite were also built in the 18th century. Saint-Marguerite was developed later, in the post-war years.

Following recurrent flooding in the valley, le Syndicat des Bassins Versants Saâne, Vienne et Scie was created in the late 1990s with the aim of reducing flooding in this whole catchment area (over 500 km2 covering the 103 member communities). From 2000 there has been much deliberation on the matter and the elected representatives wished to find a solution. A steering committee of elected representatives and engineers was set up to manage flood risk and remove barriers to migrating fish, protect water quality and resources and enhance the natural environment. Consultants were commissioned to conduct studies on hydrological, hydrogeological, socio-economic and biological aspects (terrestrial habitats, landscapes, environment).

Summary of issues

The key issues in the lower valley of the river Saâne are flood risk management and enabling the free movement of fish. The salinity of this freshwater environment needs to be monitored to ensure the biodiversity is maintained as it supports migratory bird species. The key issues in terms of land use are associated with a campsite located in a zone of high flood risk, hunting and the road infrastructure. Based on the conclusions from the latest studies, it is envisaged to restore the estuary in the lower valley.

Ongoing work and how it links with LiCCo

As part of LiCCo, on all French pilot sites there will be:

  • a study on the functionality of the environments
  • a diachronic investigation on the evolution of the shoreline and land use
  • a socio-economic study
  • a comparison of methods and results between sites at regional and cross-border level
  • an assessment of the reliability of the data gathered in the long term

The major objective for this site, as a practical case, is to give feedback on experience of the consultation process and the development of the monitoring protocol in the case of re-estuarisation. LiCCo must moreover ascertain the development prospects for the coastal zone, the coastal rivers and the estuarine outflow pipes in Seine-Maritime.

There has already been stakeholder engagement on this site which has introduced the concept of estuarine restoration and the aim is to carry on the multi-disciplinary work by launching a monitoring campaign of the site. The monitoring campaign will include socio-economic, fish, topographical and terrestrial habitat studies seeking to determine relevant indicators for the envisaged change. LiCCo will utilise the existing stakeholder networks to engage people.

LiCCo partners for the Saâne Valley site

  • Le Conservatoire Botanique National de Bailleul
  • Le Centre d’Etudes et de Recherchesur les Risques et les Vulnérabilités
  • Cellule de Suivi du Littoral Normand

Key stakeholders

  • The communities (Quibervillesurmer, Sainte-Marguerite-sur-mer and Longueil)
  • La Communauté de communes de la Saâne
  • La Communautéd’Agglomération de Dieppe maritime
  • Le ConseilGénéral de Seine-Maritime as the body managing the CdL sites, which owns the estuarine outflow pipe and the secondary road)
  • Le Syndicat de Bassin Versant (Saâne Vienne etScie)
  • La Direction Départementale des Territoireset de la Mer du département de Seine-Maritime (DDTM 76)