Roadside Guide to Clean Water: Streambank and Floodplain Restoration
Streambank and Floodplain Restoration at a Glance
Streambank and floodplain restoration is the practice of stabilizing and/or altering the stream channel to slow and direct the flow of water to reduce erosion and flooding. This practice might include regrading streambanks, installing large rocks or logs in the stream channel, or excavating the floodplain to create wetland habitat where the steep banks are located. Streambank and floodplain restoration projects require permits, heavy construction equipment, engineering, and specific expertise. Often this practice is enhanced by planting trees and shrubs next to the stream.
How Streambank and Floodplain Restoration Works
With increased development, greater volumes of water are directed into our streams when it rains than would occur in a natural setting. Higher-than-natural volumes of water flowing quickly downstream causes streambanks to erode and become unstable. Eroding streambanks contribute to sediment pollution, which makes our streams look chocolate brown during rain events. In addition, when streambanks erode, there is a risk to nearby infrastructure like bridges and culverts as well as a loss of property. To fix this, stream restoration practices can be employed to redirect the water flow into the center of the stream where less erosion will occur. Water is slowed down and streambanks are protected. Additionally, the stream can be connected to the floodplain where water will flow more slowly, letting pollutants settle out and reduce downstream flooding damage. In general, a stream or floodplain restoration project creates a more naturally functioning, stabilized stream.
Community Benefits of Streambank and Floodplain Restoration
- Climate Change: Promotes climate change resiliency
- Flooding: Mitigates flooding
- Stormwater: Reduces stormwater runoff
- Pollution: Reduces pollution
- Habitat: Provides wildlife habitat
You can expect to find streambank and floodplain restoration in urban, suburban, and rural settings.
How to Recognize Streambank and Floodplain Restoration
Steep, eroding banks like this one are good places to do stream restoration, especially since the road is at risk. Photo by Sarah Xenophon
Mud sills are essentially logs that are built into the streambank that extend over the water's surface to protect the streambank from erosion and create cover for fish. Photo by Kristen Kyler
Stream and floodplain restoration work requires a permit, engineering, and earth-moving and construction equipment. Photo by Sarah Xenophon
Some projects completely remove the streambank by excavating "legacy sediment" and creating a flat wetland that slows down water, filters pollutants, and reduces flooding downstream. Photo by Kristen Kyler
Grading streambanks to a gentle slope allows water to escape to the floodplain during storms. Logs protect the banks and create cover for fish. Planting trees provides additional benefits. Photo by Jennifer Fetter
Creating smooth, gradual bends slows water flow. This V-shaped cross-vane structure directs the flow of water and creates a small waterfall to add oxygen, which supports life in the water. Photo by Sarah Xenophon
An easy and affordable streambank restoration technique is to use branch cuttings called live stakes. These cuttings grow roots right where they are needed most to help prevent streambank erosion. To learn more, go to "Live Staking for Stream Restoration" or "Live Staking - A How-to Guide" for a live staking learn now video.
