Early civilizations like Mesopotamia, Indus Valley, and Rome demonstrated how water management impacted population and the environment. In Mesopotamia, overuse of irrigation led to soil salinization and decreased crop yields, forcing population decline. The Indus Valley implemented basic sanitation to reduce malaria, but did not sufficiently manage rivers. Rome grew to over 1 million people through engineering projects but also overused resources, requiring its capital to move. Integrated water resource management provides a framework to sustainably manage water, but must be tailored to each community.