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Floodplain Connectivity
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Read Floodplain Connectivity Stories
Rivers and streams need to use their floodplains.
In the area adjacent to rivers and streams you can find vegetated areas known as floodplains. The function of these areas is to absorb flood waters during naturally occurring high-flow events as rivers exceed the bank of the main channel, spreading out into smaller channels, and across the land.
Over time, rivers have been confined to one channel, and, in turn, these channels became disconnected from the floodplains. RRWC works to restore this connection through side channel reconnection, large wood placement, and fish passage barrier removal. These actions help improve floodplain connectivity between the stream and its adjacent floodplain offering a multitude of benefits to stream conditions, wildlife, and community health and resource protection.
As water flows over the stream's defined channel and onto the floodplain, it saturates the soil and ultimately seeps underground. This saturation supports the growth of the native plant community.
When streams are connected to their floodplains, the land is more saturated with water. This can serve as a wildfire mitigation strategy as wetter ground is harder to burn.
Floodplain connectivity also encourages hyporheic flow, which improves nutrient cycling, cools water temperature, and supports the plant and animal communities.
Floodplains During High Flow
Unimpacted rivers and streams naturally flood cyclically due to high precipitation, snow melt, and weather patterns. These flood events vary in magnitude and duration. Rivers connected to their floodplains naturally spread out the power of these high-flow events, which limits unnatural erosion and provides slower water refuge for juvenile fish. These benefits can also help protect infrastructure (like bridges and homes) by spreading out the power of the flow from one channel to multiple. Rivers and streams that are connected to their floodplains are best equipped to take on these flooding events and use them for ecosystem and community benefit.
Cascade
Stream
Solutions
Mainstem
creek with
decreased
stream flow
Underground water storage through saturation
Reconnected
seasonal side
channel
Flood waters
spreading out
across the floodplain
Large wood structure installation within the floodplain of South Fork Little Butte Creek.
Floodplain
Connection
Well Water
Recharge
When streams are connected to their floodplains, the land is more saturated with water. This saturation is not a short-term process. As the ground absorbs the water from high-flow events, it is stored underground in groundwater. Groundwater can be found in springs, seeps, and aquifers.
These groundwater sources are what contribute to water that is drawn from wells, and floodplain connectivity helps support the recharge that is necessary for the production of those wells. Additionally, with high flow events occurring in the winter and spring, this natural storage also helps increase water inputs into the drier and hotter seasons when the water stored will naturally release back into the stream.
Fly Over a Floodplain
What does a connected floodplain look like?
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