Dams are structures built on rivers that control the flow of water. The Mississippi and some of its tributaries use both levees and dams for flood control. Unfortunately, sometimes these do not work and damage occurs. Dams also have other uses. On some fast-moving rivers, dams generate electricity.
Dams also store water in big lakes called reservoirs.
The water in reservoirs is used for drinking and irrigation. Along with providing water for irrigation and drinking and making electricity, rivers help us in many other ways. For thousands of years, people have used rivers for travel and business. Although rivers aren't used as much for travel anymore, they are still used to transport goods from state to state and country to country. Flat boats called barges transport goods up and down rivers.