Sao Francisco

São Francisco 

a river in Brazil, in the Brazilian Highlands. The São Francisco is approximately 2,800 km long and drains an area of approximately 600,000 sq km. It rises in the Serra da Canastra massif. The upper course has the character of a mountain river. The river then flows through a broad tectonic valley parallel to the Atlantic coast. At the city of Cabrobó it veers sharply to the east-southeast and cuts toward the Atlantic through the coastal escarpment of the highlands, forming rapids and Paulo Afonso Falls. There are sharp variations in the rate of flow, since most of the river passes through a region that is normally very dry but has heavy summer rainstorms. The mean flow rate at the city of Barra is 3,000 cu m per sec. During the rainy season, the São Francisco is navigable from its confluence with the Velhas River at the city of Pirapóra to the city of Juàzeiro and from Paulo Afonso Falls to the mouth. The large Três Marias Reservoir, with a hydroelectric power plant, is located above the city of Pirapóra.