Latin America and the Caribbean
|Antigua & Barbuda
||Saint Christopher & Nevis
Latin America and the Caribbean, as a region, with only 8.4 percent of the global population is well endowed with fresh water resources. The region has an annual runoffof 13,120 cubic km, which represents 30.8 percent of the global total annual runoff average of 42,655 cubic km (Davis, 1996). Although more difficult to quantify, there is also abundant groundwater. The average annual precipitation in the region has beenestimated to be in order of 1,500 mm, over 50 percent of the world average (ECLAC, 1985). Therefore, it is basically a humid region.
However, there are extreme variations in time and geographical availability within and between countries. In Mexico, forexample, four major basins that cover about 10 percent of the country account for about 50 percent of the mean annual streamflow. Three South American basins, the Orinoco, the Amazon and the Plata, account for about two thirds of the region's average annual runoff. Almost 25 percent of the land in LAC (some 5 million square kilometers) corresponds to arid and semiarid regions as a result of the irregular distribution of rainfall (Aldama & Gomez, 1996). These regions are located mainly in northern and central Mexico, northeastern Brazil, Argentina and the Pacific coast of South America from Peru to northern Chile (the Atacama desert in Chile has been labeled the driest place on Earth). Smaller areas are also in Dominican Republic and northern Central America.
The mountain systems of the Sierra Madre in Mexico and Central America, continuing into the Andes mountains in South America, separates the Atlantic and Caribbean slope from the Pacific slope. The major rivers and water bodies of the region suchasthe Orinoco, Amazon and Plata are in the former, which represents 84 percent of the total area of the region. These rivers drain mainly tropical areas, have small gradients and relatively constant flow in their lower reaches. Large areas in north-easternArgentina and Paraguay are flat and flood prone. The Pacific slope covers only about 11 percent of the region's area. Its watersheds have steep slopes, many with scant vegetation cover and subject to flash flooding and mud slides and transporting large quantities of sediments. Some five percent of the region - has no direct drainage to the oceans (ECLAC, 1985).
Davis, D. (1996). "Water Resources Assessment . The Tool for a Sustainable Future", in Water Resources Assessment and Management Strategies in Latin America and the Caribbean, Proceeding of the WMO/IDB Conference, San Jose, Costa Rica.
ECLAC (1985). The Water Resources of Latin America and the Caribbean and their Utilization. UN, Santiago, Chile.
Aldama Rodriguez, A. and L. Gomez Ugarte (1996). "Capacity Building for the Mexican Water Sector Through Research, Development, Training and Education", in Water Resources Assessment and Management Strategies in Latin America and the Caribbean, Proceeding of the WMO/IDBConference, San Jose, Costa Rica.