Tunisia: MEDECO-RESTOR
Ghar El Melh, MEDJERDA DELTA, UNESCO Ecohydrology Demosite
Photos: MEDECO-RESTOR
Site description
Located downstream of the Medjerda Delta, the Ghar El Melh Lagoon (GEM), Tunisia, Mediterranean, has a complex sedimentary history, shaped by the deltaic processes of the Medjerda River over centuries. However, changes to the Medjerda river's course, the construction of dams, and the installation of port infrastructure have significantly altered the natural sediment dynamics, leading to coastal erosion exceeding 5 meters per year in some areas. This erosion poses severe threats to the lagoon, local communities, and the region's cultural and ecological heritage, which spans more than 500 years.
GEM Historical genesis results from the evolution of the coastline, in the ancient Gulf of Utique (Sinus Uncensus) which has continued to advance in the sea since the most remote times. The lagoon communicates with the sea by a single channel, called "El Boughaz" whose width is 85 m and the average depth is -2.5 m. The lagoon gradually formed in the 11th century BC until the 20th century AD with the sedimentary dynamics of the Deltaic filling of the Medjerda River. The sandy barrier that separates the open sea from the lagoon gradually formed with the filling of the former Gulf of Utique by the Medjerda River yield. Since the last decades, the sedimentary dynamics of the sandy barriers of the Ghar El Melah lagoon have been affected by hydrodynamic forcing associated with the reduction of river input of Medjerda because of the human modification of its natural course to the south since 1972, the installation of dams (1982) and of port dikes in the GEM fishing port (1975 and 1993).
Besides, the Ghar El Melh is a typical Ramsar wetland (Ramsar n. 1706 since 2007), characterized by estuarine permanent waters of the Medjerda deltaic geosystems. The Ramli agriculture system, recognized as a unique traditional practice by the FAO-ONU ( Globally Ingenious Agricultural Heritage Systems-SIPAM) in 2020, involves growing salt-resistant crops in sandy soils. This farming method is particularly sensitive to changes in salinity, water quality, and flooding patterns, which are exacerbated by climate change.
The lagoon, which has been classified as a UNESCO ecohydrology demosite since 2022, has experienced severe environmental degradation including beach retreat, water quality deterioration, marine submersion, heatwaves, and biodiversity loss. These issues are compounded by the impacts of anthropogenic activities such as excessive fishing, pollution, and dam construction, all of which are exacerbated by climate change.
Ecosystem
The benthic fauna of the lagoon has 84 species, the mollusks being best represented with 47 species and the crustaceans with 19. The lagoon also hosts a rich fauna of fish comprising 45 species which belong to 26 families. The site is home to many birds at a critical stage of their life cycle: it provides many watering birds with a place for wintering (especially surface ducks such as the Duck Sigure Anas Penelope, the Sarcelle d'Hiver A. CRECCA, The Duck Pilet A. Acuta, and the Souchet Duck A. Clypeata) and others a nesting place. Sea turtle nidification is also reported on sandy beaches since 2024. Floristic investigation reveals the presence of Cymodocea nodosa, Zostera marina, Z.nolti, Ruppia maritima, and R.cirrhosa; while P.oceanica is reported for the first time in lagoon systems of northern Tunisia, which cover ~70 ha, showing a density ranging from 56 shots/m2 to 2111 shots/m2.
Facts & Figures
2,800 ha
Total area of the Ghar El Melh Lagoon, classified as a Ramsar wetland and a UNESCO Ecohydrology demosite.
>-5m/year
Rate of coastal erosion in some areas due to changes in sediment dynamics, port infrastructure, Sea Level Rise , climate change.
84 benthic species, 45 fish species, and diverse avifauna – Including key migratory bird populations and recently documented sea turtle nidification on sandy beaches.
First documented Posidonia oceanica coverage in a northern Tunisian lagoon – A key indicator of ecosystem recovery and water quality improvement.
Location
Lagoon of Ghar El Melh (GEM) North of Tunisia, North Africa, in the northwest of the Gulf of Tunis between the coordinates 10 ° 08' and 10 ° 15 'E and 37 ° 06' and 37 ° 10 ' N.
Size
Affected areas: Since the deviation of the natural River course along the last 10 km stretches feeding the pre-estuarine floodplain covering about 2800 ha of the Lagoon aquatic system.
Restored Area: the lagoon: 2800 ha
This exceptional area holds the distinction of being a UNESCO Ecohydrology demosite and a Ramsar wetland, recognized for its unique coastal-lagoon ecosystem, its role in climate adaptation, and its potential for Nature-Based Solutions to mitigate environmental threats.
Existing projects
- ECOVAL project for Lagoon Ecosystem Valorisation & restoration ( 2022-2024)
https://www.youtube.com/watch?v=YvzLiE5MHDk
https://www.youtube.com/watch?v=hJ1JGStYWyk - EODD 2025 ( Masterclass and international training and Focus Group) https://www.ecole-odd.fr/ecole.html
- DIDON project PHC-UTIQUE 25G1001 (2025-2027) ( France/Tunisia)
- RAF1010 et IN7021 NUTEC Plastic IAEA ( UE).
- INSTM- Observation Phytoplanctonic Unity National Network REPHY (la surveillance du phytoplancton et des phycotoxines).
- ECORISCLIM/ LMM/INSTM ( National Project) (2024-2027)
- TunSea Restore NGO: Consortium Méditerranéen pour la Biodiversité (CMB) (2025-2026)
DALIA Implementation Plan
- Capacity Building and Stakeholder Engagement and Knowledge transfer
- State the physical and environmental characteristics of the pilot site by conducting a bibliography and data collection (water/sediment/biota) to identify the effectiveness of the pilot restoration.
- Replication of the DP7: Implementation of the monitoring system: Associated Pilot’s execution
- AI pre-processing to identify the water and sediment facies status.
- Modeling & forecasting the water quality, sediment flow, and dynamics in several climatic scenarios.
Involvement of the Community
Local communities, particularly fishermen and farmers, will play a key role in the restoration efforts. Through capacity-building programs, they will be trained to adapt traditional agricultural and fishing practices to climate-induced changes, ensuring the preservation of cultural heritage such as Ramli agriculture. The project will implement community-led monitoring of key environmental parameters (e.g., water salinity, sediment flow) using AI-driven forecasting tools to guide sustainable interventions. Additionally, the creation of multi-functional green spaces will enhance social cohesion, providing areas for education, recreation, and economic opportunities linked to eco-tourism and sustainable aquaculture.
Expected Impact
The monitoring of changes and flow patterns, supported by AI-based forecasting, will guide the implementation of NbS interventions tailored to address the specific impacts of climate change and anthropogenic stressors. By actively involving local communities, authorities, and stakeholders, the project ensures that interventions are not only effective but also socially inclusive and culturally relevant. This participatory approach will foster a sense of ownership and commitment among stakeholders, sustaining the benefits of the interventions and promoting the long-term resilience of the lagoon and its associated ecosystems.
Funded by the European Union
