Q: How Do Dams Protect against Flooding?
A: Dams are an important part of flood protection for any city. They protect against the potential loss of life and property that can be caused by flooding. Dams protect against flooding by collecting and holding waters when they reach a certain level. Once collected, a dam might be designed to release the water back into the river at a controlled speed or divert the water elsewhere for other uses.
One example of this is a flow-through dam, also known as a perforated dam. Flow-through dams are built solely for flood control and are used to protect against flooding in downstream areas. Because this type of dam is built solely for flood control, the opening (spillway) is at the same level as the riverbed. This means that when there isn't excess water, the river will continue its natural flow. However, when water levels rise, the dam slows the water flow through the opening to prevent flooding.
If you live in an area prone to flooding, there are probably dams like this installed along major rivers. The best part is that dams like this also prevent flooding onto farmland. This offers a broad blanket of protection where a flood would otherwise destroy a city's infrastructure and people's livelihoods.