People use rivers for transportation and as a source of natural resources. For example, people draw water from rivers to fulfill their drinking, bathing, irrigation, cooking and industrial needs. People also harvest fish, shellfish, mollusks, ducks and other food animals from rivers.
Many industries use rivers as a place to discharge their polluted water. Sometimes, this water contains harmful chemicals, while other times, the water is very hot. Hot water changes the thermal environment of the river, which may disturb local plants and fish. In some places, people use rivers as a source of power. To harness river power, people build dams on rivers. The dams allow a small amount of water to flow through a turbine, which creates electricity when it turns.
Pioneers often made their settlements near rivers. This allowed them easy access to drinking water, transportation routes and plentiful food. However, rivers flood from time to time, which can cause widespread damage, destruction and loss of life. Members of some isolated cultures still live near rivers, and they draw most of their resources from the waters. When dams are built upstream from these areas, it can cause damage to the waters that these isolated cultures depend on.