This document discusses water resources, demand, and pollution. It notes that only a small percentage of Earth's water is available for human use. Water demand has tripled since 1950 due to population growth and increased consumption. Most water is used for agriculture, with household and industrial uses also increasing. Modification of waterways and overuse of resources like the Ogallala Aquifer are concerns. Water pollution from sources like agricultural runoff, industrial waste, and mining impact water quality. The Clean Water Act helped improve many US waterways but challenges remain.

6. Demand for water 85% SW U.S. 10% 49% 41% U.S. 8% 25% 70% World Household Industry/energy Agriculture