Of the world’s total water supply, more than 96 percent is saline. The remainder, less than 3 percent, is freshwater. And, of the total fresh water, more than 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Rivers and lakes that supply fresh surface water for human uses only constitute about 0.27 percent of fresh water, yet rivers are the source of water for many people.