Summary

The Thau lagoon is situated in the Languedoc Roussillon region (South East of France), along The Mediterranean border. The Thau lagoon and its surroundings are recognized as sites of Communautary Interest, as an important conservation areas (ZNIEFF, ZICO, NATURA 2000), and the Canal du Midi which is connected to the Thau lagoon is part of world human patrimony (UNESCO).

The Thau lagoon has a surface of 75 km2 and an average depth of 4,5m (max : 10m.). It is under strong marine influence. The lagoon is connected north to the sea by the canal of Sète (90% of exchanges) and South by the Grau de Pisse Saumes. The volume of the lagoon is 280.000.000 m3. During a year a third of this volume is exported to the sea.

Main hydrological regime of rivers is intermittent, only one, the Vene has a permanent output. Precipitation show large interannual variation (from 200 to 1.000 mm per year). The population on the watershed reaches 107.000 inhabitants (density of 380 inhab.km2) with a very strong growing rate (75% on the last ten years), so urbanism are the problem in region.

Some of activities which doing in this area are Shelfish farming (more than 10% of the whole french production), fisheries (clams and fishes), Tourism and recreational activities (bathing, nautism), agriculture (wineyards), and marine industry (Sète harbour).

Most of activities are potentially as a cause of the environmental pressure. Some case are happened ie: Harmfull Algae bloom (PSP : Alexandrium and DSP: Dinophysis); bacteriological contaminations, anoxias, biodiversity changes, alien species (macroalgae), nutriment fluxes, trophic balance changes.

Much effort has been put into the setting up of a first integrated management programm (SMVM for Schema de Mise en Valeur de la Mer) which defines priorities of action about shelfish farming and offer a spatialised plan for the developpment of concurrential activities in the lagoon and on a part of the watershed. The main drawback of this SMVM (the first to be adopted in France) is its fixed frame which is difficult to make evoluting as decision for evolution/modification has to be taken at the summit of the French state (Conseil d’Etat). Other efforts have been put in works on the watershed (Two Contrats d’Etang) as to optimise waste water processing in relation with the occurrence of bacteriological contamination of lagoon waters and shellfish.

The Project will be setting up of a first integrated management plan (SMVM) with priority to shellfishculture activities in the lagoon.

The Thau lagoon is situated in the Languedoc Roussillon region (South East of France), along The Mediterranean border

For additional information

Systems Approach Framework (SAF)

Contribution following the SAF sequence, that is the system design volume followed by the system formulation volume, the system appraisal volume and finally the system output volume.

Powerpoint presentation at the Cluster Meeting Thessaloniki 20-21 Oct 2009:

Date: 2007-2011

SPICOSA local applications aim to bridge the gap between coastal stakeholders across various aspects of local economy, policies, uses, conflicts and impacts to enable the dialogue that may lead to sustainability.

Coordination by Thierry Laugier, Ifremer

Characteristics

Marine System

The Thau lagoon has a surface of 75 km2 and an average depth of 4,5m (max: 10m.). It is under strong marine influence. The lagoon is connected north to the sea by the canal of Sète (90% of exchanges) and South by the Grau de Pisse Saumes. The volume of the lagoon is 280.000.000 m3. During a year a third of this volume is exported to the sea. As tide is very weak (10cm.), the wind is the main factor of water masses transport. Wind is often strong, particularly when blowing from the NW with a mean of 118.5 days per year above Beaufort

force 5. The climate imposes a wide range of water temperatures and salinities with minima of 5° in january and salinity near 27 and maxima of 29° in august and salinity reaching 40.

Watershed

Watershed has a surface of 280 km2. Main hydrological regime of rivers is intermittent, only one, the Vene has a permanent output. Precipitation show large interannual variation (from 200 to 1.000 mm per year). The population on the watershed reaches 107.000 inhabitants (density of 380 inhab.km2) with a very strong growing rate (75% on the last ten years).

Human Activities

Shelfish farming (more than 10% of the whole french production), fisheries (clams and fishes), urbanism, recreational activities (bathing, nautism), health activities (thermalism, thalassotherapy; 2nd french site), agriculture (wineyards), marine industry (Sète harbour)

Impact Responses

Harmfull Algae bloom (PSP: Alexandrium and DSP: Dinophysis); bacteriological contaminations, anoxias, biodiversity changes, alien species (macroalgae), nutriment fluxes, trophic balance changes.

Policy

Policy issues

Much effort has been put into the setting up of a first integrated management programm (SMVM for Schema de Mise en Valeur de la Mer) which defines priorities of action about shelfish farming and offer a spatialised plan for the developpment of concurrential activities in the lagoon and on a part of the watershed. The main drawback of this SMVM (the first to be adopted in France) is its fixed frame which is difficult to make evoluting as decision for evolution/modification has to be taken at the summit of the French state (Conseil d’Etat)

Other efforts have been put in works on the watershed (Two Contrats d’Etang) as to optimise waste water processing in relation with the occurrence of bacteriological contamination of lagoon waters and shellfish.

Policy changes

On the basis of the implementation of the WFD (particularly considering bathing waters and shellfish waters quality) policy changes have been implemented as to take the place of the SMVM policy issue. Those changes apply to:

  • a third Contrat d’Etang (Contrat Qualité) directly dedicated to the water quality of the lagoon and environmental management procedures (ISO 14001),
  • a SCOT (Schema de COherence Territorial) and iii/ a SAGE (Schema d’Amenagement et de Gestion des Eaux) including an integrated territorial approach between the lagoon and the watershed.

Stakeholders and Institutional Governance

Major organisations

Syndicat Mixte du Bassin de Thau. (SMBT) This organisation has been set up recently (2005) and results from the fusion of two territorial communities corresponding to the southern and northern part of the lagoon and its watershed. The SMBT is nowadays the unique organisation in charge of the implementation of integrated management of the lagoon and its watershed and in charge of the implementation of the three management tools which are the Contrat Qualité, the SCOT and the SAGE.

Other leading organisations

  • Cepralmar: an organisation depending from the Languedoc Roussillon regional council in charge of the relationships with the sea professionnals
  • Conseil Général de l’Herault who has responsabilities on the infrastructures development on the territory

Partner Collaboration

  • GEYSER (Mediation)

Systems Studies

Long time series

Hydrological, hydrochemical, microbiological, phytoplancton, macroflora and macrofauna, river discharges, nutriments loads, meteorology, hydrodynamism, sediments, heavy metals, organic contaminants but also land use dynamics, economical statistics, administrative limits and rules evolution. Some of the data series start from the end of the second War (1947).

Research Projects and Socio-economic study

  • PNEC (Programme National en Ecologie Côtière) chantier lagunes méditerranéennes started in the year 80 (understanding of the ecological mecanisms, management tools development and integration of socio economic studies)
  • Institutional monitoring networks : RNO (1975), REMI (1984), REPHY(1992) and regional RSL (Réseau de Suivi Lagunaire started 2000;
  • Syscolag programme (see http://www.syscolag.org/) dedicated to the setting up of a shared knowledgee data base including metadata service, and GIS implementation
  • Dynamic atlas of Thau lagoon developped in the framework of Githau/Syscolag (ICZM of Thau lagoon) and RSL projects
  • DITTY european project (development of a Decision Support System for the management of southern mediterranean lagoons)
  • Implementation of Sustainable and ICZM indicators programme (launched with the socio- economist team of Montpellier University).

Photo: © Christian Ferrer / Wikimedia Commons