Source: The Library Of Congress Country Studies
The Mananara and Mangoro rivers flow from the central highlands to the east coast, as does the Maningory, which flows from Lake Alaotra. Other rivers flowing east into the Indian Ocean include the Bemarivo, the Ivondro, and the Mananjary. These rivers tend to be short because the watershed is located close to the east coast. Owing to the steep elevations, they flow rapidly, often over spectacular waterfalls. The rivers flowing to the west coast and emptying into the Mozambique Channel tend to be longer and slower, because of the more gradual slope of the land. The major rivers on the west coast are the Sambirano, the Mahajamba, the Betsiboka (the port of Mahajanga is located at the mouth), the Mania, the North and South Mahavavy, the Mangoky, and the Onilahy. The Ikopa, which flows past Antananarivo, is a tributary of the Betsiboka. The Mangoky River has a basin area of some 50,000 square kilometers; the Ikopa River and the Betsiboka River have basin areas of 18,550 and 11,800 square kilometers, respectively. The principal river in the south, the Mandrare, has a basin area of some 12,435 square kilometers, but it runs dry during certain months in this desert region. Important lakes, aside from Alaotra, include Lake Kinkony in the northwest and Lake Ihotry in the southwest.