Demand, supply- surface water
Satellite pictures of the Earth at night clearly demonstrate that people congregate and live where they can have access to water, especially freshwater. Freshwater makes up only about three percent of all the Earth’s water and it may surprise you even more to know how little of this supply is actually freshwater that can be seen. Surface water is literally a drop in the bucket. A mere 0.29 percent of the Earth’s total freshwater supply is found in lakes and swamps.