Moëze Marsh

Located on the coastal fringe of the Brouage marshes, between the Marennes peninsula to the south and the Moëze hills to the north, the Moëze marsh was gradually formed over time by the progressive silting of the Gulf of Saintonge by the alluvium from the Charente River. Slowly transformed by humans into salt marshes through digging and embankment, today’s marsh retains this heritage in its typical landscape of raised mounds (bossis) and canals.

After the gradual abandonment of the salt pans, the former saline plots in the heart of the marsh gradually silted up and were converted from the 19th century onward into hay meadows and pastures for extensive livestock grazing, while some areas along the coastal zone were re-dug and reused for oyster farming. More recently, parts of the marsh have been drained to allow cereal cultivation.

This site includes a wide range of wetlands that support the establishment and development of remarkable biodiversity. Located right in the heart of a migratory route and featuring suitable habitats , the site is of major importance for the wintering, refuge, and migration of many waterbirds and has been partly occupied since 1985 by the Moëze-Oléron National Nature Reserve.

On this vast marsh, rich in historical, natural, and human heritage, the coastal dike is weakened by recurring climatic hazards. Several management and coastline evolution scenarios need to be studied to determine the future of the site.

Project actions and outcomes

The earthen dike located along the seaside at the Moëze site is repeatedly battered by waves and swell, causing frequent maintenance issues. The scarcity of materials needed for these works makes it increasingly difficult to keep this structure in good condition. Further north, a dune ridge weakened by erosion provides coastal defense. In this context, the Conservatoire aims to support the site’s evolution through a collaborative and shared approach.

To this end, various coastline management scenarios will be studied and analyzed based on local concerns related to landscape, biodiversity, economy, and social perception. This will provide elements for reflection, support for consultation, and aid in decision-making.

Chronology

• 2016: Conducted a historical and landscape diagnosis of the Brouage marsh – ENSP.
• March 2017: Presentation of the landscape diagnosis at the Marshes Forum.
• March to August 2017: Agricultural diagnosis carried out – Cdl / CA17.
• August 2017: Presentation of the agricultural diagnosis to the marsh farmers.
• October: Signing of Life Adapto.
• January 2018: Launch of BRGM study modeling different coastline management scenarios.
• May 2018: Technical committee – presentation of the development of the BRGM hydrodynamic model.
• September: Technical committee – presentation of the first BRGM modeling results.
• February 2019: Committee of mayors of the Brouage Marshes Agreement – presentation of the first coastline management scenarios.