National Geographic : 1993 Jun
Profile of a liquid land If the Himalaya are the "roof of the world," then Bangladesh-prostrate at their base-is the drain. Mak ing up only 8 percent of the 600,000-square-mile Ganges S ... Brahmaputra-Meghna basin , ° . i ..f 1 . " . ;"* - - - . * (blue outline, right), Bangla desh funnels nearly all the outflow to the Bay of Bengal. Fed by Himalayan snowmelt and copious rains, Bangladesh's great rivers race southward, slicing off chunks of precious land and flooding one-fifth of the nation annually. The country's burden is also its lifeblood. Bangladeshis rely on the flooding to renew fish stocks, groundwater, and soil. Carrying two billion tons of fer tile silt a year, the rivers help balance erosion by forming new land through silt accretion. Efforts to control flooding and flow with embankments can upset this balance-and are often futile. Willful rivers have breached much of the 2,500 miles of embankments already built. Bangladeshis remain at the mercy of the waters that daily redraw their map.