Mantasoa Reservoir

Mantasoa Dam is a buttress dam on the Varahina-North River, a tributary of the Ikopa River, near Mantasoa in the Analamanga Region of Madagascar. The dam was constructed by French contractors between 1937 and 1938. It creates Lake Mantasoa which has a surface area of 20 km2. The dam itself is made of 8,000 m3 of concrete and has a reinforced buttress design. Water released from the dam supplies a regulated flow to hydroelectric power station at the Antelomita Dams downstream. A saddle dam on the north side of the Mantosoa reservoir regulates water flow into the Mandraka River for the Mandraka Dam downstream.

Source: Wikipedia