Floodplains are essential for the health of a river. Rivers regularly have floods and, in their natural state during these floods, rivers expand into flat areas next to the river, covering the riverfront land. This ability to expand helps to absorb the overflow and slows the force of the water downstream.
These floodwaters also bring important nutrients to the land next to the river—helping riverside trees and plants to provide essential habitat for insects and animals living near the river. As people began to develop areas along the Sacramento, they often built dikes to control the river’s overflow. These dikes and levees had the unintended effect of raising the water level and speeding up its flow—causing unexpected damage.
Today, we understand that it is often better to build floodplain areas next to the river in addition to dikes—these floodplains allow for a more natural and safe way to limit damage downstream, in addition to improving the healthy ecology of the riverside.