Nouvelle-Aquitaine-Range of solutions to slow down the water cycle

Le Marais poitevin

The image shows all the Regional Natural Parks in France. The Marais poitevin one is shown in green and is located in two demographic regions: The Nouvelle-Aquitaine Region and the Pays de la Lore Region.

Type of Landscape: Marine & Coastal

Ecosystem

Located between Niort and the ocean, the Marais poitevin is an area of great ecological richness due to the diversity of its natural environments, it is the first wetland on the Atlantic coast. At the crossroads of several major climatic zones and at the interface of land and ocean, it offers sites suitable for migratory birds.

For further information: Marais poitevin, structure du Parc naturel régional (parc-marais-poitevin.fr) and https://biodiversite.parc-marais-poitevin.fr/

Important wetland on the French Atlantic Coast

A remarkable natural heritage

Introduction

The focus in Nouvelle-Aquitaine is to support a downstream humid area (Marais-poitevin), to amplify the role of groundwater in the global water balance of the humid area and mitigate saltwater intrusion towards the coastal part of the area, in addition to monitor and simulate the impacts of the tested solutions on the climate change adaptation on the considered humid area.

In the Marais poitevin, the emergence and quick aggravation of water scarcity issues need to be addressed with a combination of NbS that amplifies the role of groundwater and its interplay with canals and other water bodies. The aim is to combine continuous water presence throughout the wetland with availability of quality usable water for needs linked to human settlements, agricultural and pastured land, wooden areas, biodiversity, while mitigating the risk of saltwater intrusion into the coastal part of the Marais. The central stakeholder for the demonstration is a regional nature park. Monitoring of multiple data sources and indicators and sharing of climate-relevant information and knowledge between expert scientists and local communities is key to success of the project.

Specific NbS tailored for the Nouvelle-Aquitaine Region

The Parc Naturel Régional (PNR) du Marais poitevin and the Syndicat Mixte du Bassin Versant de la Sèvre Niortaise have planned to carry on the restoration of river morphology. The aim of the NBRACER project is to determine if there is a response on the watertable to these superficial changes.

Restoration of river morphology through sediment recharge

Some changes have already been made in short sectors of the river to see if there was already a response in the environment. The works was done in September 2023 an even it is soon to determine the benefices, fish numbers have already increase.

Some of the changes are listed below. However, further campaigns will allow to determine new restoration spaces and new captors positions;

Environmental Challenges

Keeping water into the wetland is a main issue. However, it exists some challenges like: Insufficient socio-economic buffers to encourage these approaches, overflows annoying for neighbouring crops that could create some tension with certain farmers. This is why it is very important to involve society in the process.

Policy Support

This action is part of the implementation of the GEMAPI competence (Management of aquatic environments and flood prevention) of the Mixed Syndicate of the Sèvre Niortaise Basin and the objectives set by the SAGE (water development and management plan) Sèvre Niortaise Marais poitevin. The demonstrator is located within the perimeter of the Marais Poitevin Regional Natural Park, a Natura 2000 site.

Expected impact of NBRACER

The NBRACER project aims to determine if there is a change or response in the water table and try to measure it in time.