Integrated Water Management in a Mediterranean Coastal Watershed

This case study focuses on water management challenges and opportunities in the The Coastal Constantinois Basin and Seybouse basin (CCB&SB) of Algeria, with particular attention to the Constantine Coastal Watershed. Located in the extreme northeast of the country, the watershed extends over 2,878 km² and represents one of Algeria’s most hydrologically complex and productive coastal systems.

The Constantine Coastal Watershed integrates a dense network of surface and subsurface water resources, including:

• Four natural lakes: Tonga, El Mellah, Oubeira, and Lake des Oiseaux
• Three major dams: Cheffia, Mexa, and Bogous
• Twenty-four hillside dams, supporting local water retention and irrigation

At the subsurface level, the basin hosts the Annaba coastal aquifer, a strategic groundwater body that naturally discharges toward the Mediterranean Sea and plays a central role in regional water security.

Water resources in the basin underpin a predominantly agro-silvopastoral system, supporting both rainfed and irrigated agriculture. Key irrigated perimeters include:

• Bounamousa (14,800 ha)
• Cheffia (250 ha)
• El Frin (250 ha)
• Mouaissia (100 ha)
• Zeribi (110 ha)
• Souarek (50 ha)

These areas sustain a diverse range of crops and rural livelihoods, making reliable water availability a critical economic and social concern.

The region experiences a sub-humid Mediterranean climate, characterized by wet winters, which drive surface runoff and reservoir recharge, and dry summers, leading to high irrigation demand and pressure on groundwater resources. This strong seasonal contrast amplifies competition between agricultural use, ecosystem needs, and coastal aquifer protection.

Key Water Management Issues

• Balancing surface water storage, groundwater abstraction, and environmental flows
• Protecting the Annaba coastal aquifer from overexploitation and salinization
• Coordinating dam operations, hillside reservoirs, and irrigation demand under increasing climate variability

The Constantine Coastal Basin exemplifies the interdependence of surface water, groundwater, and agriculture in Mediterranean coastal regions. It provides a critical testing ground for integrated water management approaches that aim to strengthen climate resilience, safeguard coastal aquifers, and sustain productive agro-ecosystems under growing hydrological stress.