Vieux Salins d’Hyères

The Vieux Salins d’Hyères site was acquired by the Conservatoire du Littoral in 2001. The protected area covers 365 hectares, making it a major protected natural space in the Hyères harbor. Along with the Salin des Pesquiers, it bears witness to the former salt production activity that was a cornerstone of the local development of the Hyères harbor. The site’s governance is managed by the Conservatoire and its partners (the Toulon-Provence-Méditerranée Agglomeration Community (TPM), the municipality of Hyères, and the Port-Cros National Park).

The current management plan organizes hydraulic management of the site similar to the former functioning of the salt marshes, with the aim of optimizing ecological and ornithological quality. However, this configuration is challenged by several phenomena, notably erosion of the dune ridge to the south: coastline retreat, loss of Aleppo pines and shaded areas, beach scouring, and threats to the site’s hydraulic structures.

The rock armor present on part of the site limits erosion where it is installed but directly amplifies it downstream of the sediment transport, disrupting the hydro-sedimentary functioning at the bay scale.

Studies conducted by BRGM and Aix-Marseille University have shown that this coastal wetland is a favorable site for implementing adaptive management actions for the coastline and natural areas, such as the removal of rock armor from the coastline with a view to renaturation.

Following an initial phase of rock removal over 100 meters at the western end of the structure, the manager TPM launched a study in 2017 (Artelia) to define a management strategy for the coastal ridge. This study explores the following options:

• A protection scenario (hard protection with dikes, etc.),
• A scenario to accompany the site’s evolution according to hazards,
• A renaturation scenario with natural rebalancing of the coastline,
• A no-action scenario.

The steering committee ultimately decided to combine two scenarios: “renaturation of the coastline” and “accompanying the site’s evolution through ecological engineering operations.”

The works and the project for this site are part of two European projects: Marittimo (Franco-Italian Interreg 2017–2019) and adapto (2017–2021).

Project actions and outcomes

The overall project aims to restore a natural dynamic to the dune-beach system that forms the interface between the sea and the wetland. To achieve this, the plan is to remove the rock armor and then gradually adjust the facilities and public access according to the environment’s evolution.

The adapto actions will focus on organizing the follow-up to the major works carried out under the Marittimo project (removal of the rock armor).

This will include ensuring continuity of the coastal promenade during bad weather by creating an alternative path and monitoring the evolution of the lagoon ecosystem, including the Posidonia seagrass beds that fringe the beach.

More generally, the project will develop actions directed towards users, the local population, and elected officials to address their concerns and prepare future changes together.

Chronology

• February 2019: Contract awarded for the construction of the pedestrian path and for the rehabilitation of the dune cordon and rock removal.
• April 2019: Start of the works; presentation of the exhibition on the project created as part of the educational activity by CPIE Côte Provençale and site visit with around thirty participants.
• July 2019: Completion of the construction of the path and restoration of the dune cordon.
• September 2019: Contract awarded for the monitoring of seagrass beds and start of the study.
• October 2019: Completion of rock removal works over 340 meters of coastline.
• April 2020: Second monitoring campaign of the seagrass beds.
• August and October 2020: Social perception surveys conducted among site users.
• October 2020: Extension of rock removal over an additional 275 meters. The Vieux Salins coastline has thus been renatured over more than 600 meters.
• September 2020: Third monitoring campaign of the seagrass beds.
• November 2020: Field trips for 4 classes from Hyères primary schools: discovery of the Vieux Salins and land art workshop on the theme of natural and artificial evolution of the coastline.
• September 2021: Fourth monitoring campaign of the seagrass beds.