National Geographic : 2001 Nov
zima. The word means "alive." Yet the life of Kenya's Mzima Springs is largely born of ash and dung. In the neighboring Chyulu Range (right) stand porous peaks of volcanic ash, whose youngest cones formed about 500 years ago. Rising 7,000 feet above an arid plain, these hills trap up to three feet of rain each year from moisture-laden winds. All that rain soaks into the sponge-like ash and percolates down until it hits impervious bedrock and begins its underground journey to Mzima Springs, some 25 miles away. Filtered over many years, the pure water gushes forth at a steady pace of more than 50 million gallons a day, creating an oasis at the heart of Kenya's Tsavo West National Park. We camped there for two years with our two young sons, studying Mzima's hippos, whose copious deposits of dung nurture a pyramid of life. Cool and shallow, a shaded spring offers buoyant relief to a herd of ponderous hippos, one of four groups that loll all day in the protected waters of Mzima's three main pools. By night the hippos graze on nearby grasslands. When they return, their yel lowish waste fertil izes the water with vital organic matter.