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Rebuilding Floodplains

Floodplains are the land adjacent to the stream that is subject to flooding when a stream overflows its banks. They are an important part of the riparian zone and the health of our streams. Unfortunately, floodplains are often one of the first things to be lost when development occurs along streams and rivers.

Floodplains allow a stream system to store and absorb floodwaters, dissipating their destructive energy. As floodwaters spread out and slow down on the floodplain, sediments drop out and deliver life giving nutrients. Banks are protected from excess erosion, the stream is flushed of organic materials and pollutants, riparian plants thrive, and cleaner water is returned to the stream. It’s a win-win all around!

We can’t say it enough. Functioning floodplains are critical to the health of our streams.

Reshaping banks and reconnecting this missing link wherever space allows is a priority for all of our stream restoration projects.

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Erosion

Floodplain Riparian zone Flood prone elevation Bankfull elevation Aquatic zone Floodplain Riparian zone Uplands

Erosion. Is it good or bad?

It depends! Erosion is a natural stream process. Banks move and erosive forces shape and reshape the channel and floodplain. Sediments deliver nutrients that support life above and below the water.

But when development and stream alterations put stresses on a natural stream system, erosion can accelerate beyond the norm. This leads to unstable banks, a diminished capacity to handle floodwaters, and degraded water quality and habitat.

Protecting trails, roads, homes, etc. takes precedence along urban rivers. With natural channel design we can balance both the need for safety and the health of the stream.