Oxbows
Restore old river scars to boost nitrate filtration, provide fish habitat, and re-use nutrient-filled sediment.
How an oxbow forms
And how they are restored
An oxbow is a U-shaped floodplain wetland adjacent to a stream or river that receives tile drainage water. It performs multiple functions, including reducing nitrates in water, providing flood water storage, and creating habitat for wildlife species that live in shallow water.
In agricultural areas, oxbows can disappear due to soil erosion in surrounding land. These wetlands fill with sediment and organic material, becoming isolated from the main river channel.
But fear not – oxbows can be restored and maintained by excavating the area and reconnecting the wetlands to the river. The process takes minimal time and does not interfere with farm operations.
Benefits at a Glance
Filter 62% of nitrates from water
Store up to 1 million gallons of water per acre
Slow stormwater and intercept floodwater
Provide habitat for 57 fish species and 81 species of migratory birds and waterfowl
Oxbows Provide Shallow Water Habitats For:
Topeka shiner, Orange-spotted sunfish, Leopard frogs, Chorus frogs, Waterfowl …And many more unique species!
Best sites for restoration
Look for scars along a stream
- Floodplains
- Along a stream or river with no signs of channel instability
- Avoid steep banks, bank sloughing, and bank undercuts
- Topography that allows for a basin footprint of 1-2% the size of the drainage area for best nitrate filtration
The Restoration Process
Step 1:
Dig out the sediment and reconnect the oxbow to the stream, river, or creek.
Step 2:
Reseed the banks and disturbance areas with native plants and grasses to provide bank stabilization and habitat for birds and pollinators.
Step 3:
Haul the excavated soil to an adjacent field. This soil will be nutrient-rich and should help increase crop yields.
Step 4:
Watch diverse wildlife return to the oxbow as it collects and filters water.
Partner Spotlight: Iowa’s Oxbow Restorers
A group of seven organizations are collaborating to restore oxbows across Iowa. Their impact is impressive! They’ve documented 81 bird species and 56 fish species in restored oxbow sites. They’ve increased floodplain water storage by an estimated 48 million gallons. And the endangered prairie minnow, the Topeka Shiner, is making a comeback, because it loves the calm waters of oxbows. Read more about their work here.
Cost-Share Options
Oxbow restoration costs vary by location, watershed, and design. Fortunately, there are many state, federal, and private financial assistance programs that provide funding for oxbow restorations:
Contact your local USDA Service Center to find more cost share opportunities in your area.
Getting Started
To learn more about oxbows, visit The Nature Conservancy of Iowa and talk with your local NRCS office about getting started.
More Resources
Here are more helpful resources on oxbows:
Oxbow Restoration Toolkit – The Nature Conservancy provides steps for implementing or restoring oxbows on your land
Iowa State University College of Agriculture and Life Sciences has more details on the impacts of restored oxbows