Many of the great rivers of the world snake through different countries and different states and have historically been used to identify borders. For this reason their proper management and protection requires a high level of cooperation amongst governments.
Rivers are often managed or controlled to make them more useful and less disruptive to human activity.
- Dams or weirs may be built to control the flow, store water, or extract energy.
- Levees may be built to prevent run-off of excess river water in times of flood.
- Canals connect rivers to one another for water transfer or navigation.
- River courses may be modified for navigation, or straightened to increase the flow rate.