ATIN AMERICA IS BLESSED WITH AN abundance of fresh water. The region contains our of the world's 25 largest rivers-the Amazon, Paranm, Orinoco and Magdalena-and their combined run-off of 5,470 cubic miles almost equals the combined run-off of the other 21. Some of the world's large lakes are also located in Latin America, including Maracaibo in Venezuela, Titicaca in Peru and Bolivia, Poopo in Bolivia, and Buenos Aires, shared by Chile and Argentina. Twenty percent of global runoff-the renewable water source that constitutes our fresh water supply--comes from the Amazon Basin alone. With one-fifth of the globe's water resources, Brazil on its own has more water than any other country The region as a whole has one of the highest per capita allocations of fresh water in the world-a little less than 110,500 cubic feet per person per year. Geography, pollution and social inequality, however, badly skew Latin Americans' access to water, and very few consume anything near their full personal allocation. As a relatively parched country, Mexico has a miniscule potential supply of approximately 13,000 cubic feet per person. Natural desert is merging with a spreading human-induced desert over much of the Valley of Mexico, the country's cradle of pre-conquest civilization and presentday home of the nation's capital. Once called the "Venice of the New World" due to its being built atop a lake and intersected with canals, Mexico City is now sinking in on itself as it drains the last of its accessible aquifers from the lakebed below. This is a legacy of the conquering Spanish, who used slave labor to dismantle the more sustainable water systems of the original inhabitants. In South America, human-induced salination is causing desertification in significant parts of Peru, Bolivia and northwestern Argentina. In total-factoring in the large natural deserts of Patagonia in southern Argentina and the Atacama in northern Chile-about 25% of Latin America is now arid or semi-arid. Most of the Caribbean is also fresh water deprived, since the islands are too small to have substantial rivers. 2 Poor farming practices, unregulated industrialization and urban poverty have massively and negatively affected Latin America's water resources. Booming, concentrated populations in Latin America's mega-cities are devouring and contaminating their water supplies, forcing officials to seek out increasingly distant sources. In most large cities, over 50% of the water supply is lost through infrastructure leakage. Some cities lose almost 90% through leaky pipes.3 Mexico City now depends on aquifers for 70% of its water and is mining these underground sources up to 80 times faster than they are naturally replenished. Meanwhile, Sao Paulo is threatening residents with water rationing. The city is relying on sources farther and farther away, hiking the cost of delivery beyond many peoples' ability to pay for it. Throughout the region, water basins and aquatic habitats are routine dumpsites for garbage, mining effluent, and industrial and agricultural waste. Pollution in the waterways along Gold mini ng refuse, carrying mercury, threatens the Amazon's waterways.