The Mangoky River Delta, Madagascar – April 25th, 2009
The 564 kilometer long Mangoky River flows down from Madagascar’s central highlands, emptying tan sediments into the Mozambique Channel.
The eastern half of the basin drains Pre-cambrian sediments, according to the World Delta Database, while the central and western basin drains a prominent series of north-south oriented Mesozoic fold belts.
The channel in the well-defined alluvial valley displays a braided pattern, with numerous mid-channel islands. The climate in the alluvial valley is quite dry and exposed sandy islands dot the main river course.
The delta displays a fan-shaped pattern and has two main distributaries.
The average annual river discharge is 526 m3/sec with a maximum of 1,621 m3/sec, which occurs in January and a minimum of 93 m3/sec which occurs in October. Thus the discharge pattern is displays extremely erratic discharge characteristics.
Further inland, south of the delta, is Lake Ihotry. It is a closed saline lake, and appears greenish-tan in color due to silt.
The area between the lake and the shoreline contains many ponds, also containing much silt, and a whitish patch of sand.