Diama Dam, Gravity dam and border crossing on the Senegal River, Senegal and Mauritania

Diama Dam is a gravity dam on the Senegal River at the Senegal–Mauritania border, near the village of Maka-Diama. Its main section, 170 m long, holds a ship lock 175 m by 13 m and a spillway with gates; a 440 m embankment section and a dike extend north to the river's edge. The dam is 18 m tall and its spillway discharges up to 6,500 m3/s.

The project began in 1981 and was completed in 1986 as a joint effort between Senegal and Mauritania. Once finished, it became an important tool for managing the Senegal River between the two nations.

The dam represents a joint infrastructure project between Senegal and Mauritania, supporting agricultural communities through water management and irrigation systems.

There is a road crossing for vehicles and a lock operation for river boats wishing to pass through the structure. Daytime crossings work best when the gates are open and staff are present.

The dam is a movable barrier: its gates open during floods to let the river flow and close during low water to block the upstream push of salt water, which once reached 250 km inland. Its 175 m by 13 m navigation lock lets boats pass the structure.