Oxbow Wetland

The Nature Conservancy in Iowa, the City of Johnston and Polk Soil & Water Conservation District have joined together to restore an oxbow along Beaver Creek within the City’s Beaver Creek Natural Resource Area. An oxbow is a meander of a stream, cut off from the present flow of water. Over time, some oxbows fill in with sediment, no longer able to offer the benefits they once provided. Restoring and maintaining oxbow wetlands offers multiple benefits, including improving water quality, increasing flood storage capacity and improving wildlife habitat. This location, as shown on the map below, was chosen as it was formerly a meander in Beaver Creek and is already a low-lying depression area that often has standing water within it.

“This oxbow restoration project is a perfect way for the City to showcase one of the many ways stormwater can be creatively managed in an urban environment. We look forward to residents being able to interact and enjoy the many benefits that will result from this project,” said David Wilwerding Community Development Director.

The restoration project is scheduled to begin the week of August 19th with construction anticipated to last three to four weeks. During this time, park and trail users within the Beaver Creek Natural Resource Area are asked to use caution as trucks and heavy equipment will be in use, including the frequent crossing of the trail as contractors remove soil from the restoration site. Additionally, one segment of the trail, just south of the bridge to Green Meadows West will be closed for several days to allow the connection to Beaver Creek to be made; this work is scheduled for mid-September. All trail crossings/closures will be clearly marked, so users are advised to obey the construction signage.

Based on research conducted on other oxbow wetland restoration projects in Iowa, this restoration project is expected to provide the following benefits:
  • Improved water quality – restored oxbows have the natural ability to remove up to 90% of the nitrate entering them from floodwaters.
  • Increased flood storage – oxbows are shown to store up to one million gallons of water per one acre of oxbow and can divert stormwater, slowing water flow and decreasing erosion rates.
  • Additional fish habitat – restored oxbows provide critical habitat for young fish to grow before entering the stream as adults. Fish surveys completed in restored oxbows have found 31 species of fish thus far, most of which can be found in Des Moines streams.
  • To learn more about oxbow restorations, visit www.nature.org/IAoxbow 
The Nature Conservancy in Iowa jointly funded this project with a grant from the Wildlife Conservation Society Climate Adaptation Fund, and the City of Johnston through its stormwater utility fund with engineering and construction administration services provided by Polk Soil and Water Conservation District.
Aerial Map