Dams and Levees
Both levees and dams are built to offer flood protection for those adjacent to or downstream from a body of water prone to flooding.
LeveesLevees reduce the risk of flooding, but no levee system can eliminate all flood risk. A levee is built parallel to a body of water (most often a river) in order to protect lives and properties behind it from some level of flooding. There is always the chance that a flood will come along that exceeds the capacity of a levee, no matter how well it was built. If a larger flood occurs, floodwaters will flow over the levee. The risks and actions to take to reduce those risks are explained in the brochure: So, You Live Behind a Levee Levees are regulated by the Illinois Department of Natural Resources, Office of Water Resources (IDNR-OWR) under the 3700 Rules. |
Dams
A dam that is built for flood protection is usually designed to lower the amount of water going downstream of the dam by containing excess water and releasing it slowly over time. Unlike levees, dams may serve purposes other than flood control, such as water supply, irrigation, livestock water supply, energy generation, containment of mine tailings, recreation, and pollution or flood control. Many dams fulfill a combination of these functions.
The risks and actions to take to reduce those risks are explained in the FEMA brochure:
Know Your Risks
FEMA P-956 / February 2013
Within Illinois, dams are regulated by the Illinois Department of Natural Resources, Office of Water Resources (IDNR-OWR) under the 3700 Rules.