The CADILLAC DESERT series' fourth and final episode, Last Oasis, offers an eye-opening report on the ways in which water use affects people's daily lives.

Based on Sandra Postel's book Last Oasis (W. W. Norton, 1992; reissued 1997), the episode begins with the story of how America's large dams became examples for water projects abroad, particularly in developing countries. On the Narmada River, India is building the Sardar Sarovar Project, which will ultimately displace 100,000 people; in China, the Three Gorges Dam, the world's largest dam project, will flood an area as famous as the Grand Canyon and displace over one million people. Although the World Bank, long a funder of large dams, has withdrawn from both projects, both countries have vowed to go forward. Mexico City, struggling to provide water for its growing population, is sinking -- in some sections up to 12 inches a year -- due to overdrawn aquifers. In the volatile Mideast, conflicts over the limited waters of the region are only further straining tense relationships. Back home in Denver, Colorado, the victory by environmental groups in blocking the building of the Two Forks Dam on the South Platte River led not only to the protection of the spring sandhill crane migration in nearby Nebraska, but spurred conservation techniques such as home water meters and "xeriscape," a water-saving landscaping practice. The program's final stop is south of the U.S.-Mexican border in the Colorado Delta, where the once verdant land has been turned into a dead zone -- miles and miles of cracked and dried-out salt flats -- due to the damming and diverting of the Colorado River upstream.

Media, Conservation, Latin America, Media