Water is a resource that humanity has gone to great lengths to obtain. We have tried to save rainwater, dug deep wells, diverted rivers, created lakes, built long aqueducts, and spent huge amounts of energy to desalinate sea water. In the process we have often ruined good cropland by making it too salty to grow crops. We have fought wars over water supply, and will do so again. What percentage of the Earth's water is freshwater available from lakes and rivers