Oxbow Restoration Benefits Wildlife, Landowners, Communities, and the Bottom Line
Rivers naturally want to curve and meander through our landscape. Over time, the force of the water erodes through bends and river banks causing portions of the old channel to become abandoned as the river creates a new path. These abandoned channels in the river are called oxbows.
In the 20th century, landowners straightened rivers to increase land availability. Floodwaters, instead of soaking into the water table, sliced straight down the river channels, which in turn increased erosion, nutrient runoff, and the likelihood of downstream floods. At the same time, landowners began spreading manufactured nitrate fertilizer on their fields. That nitrate washes out into river channels, contaminating water sources.
Over time, many oxbows dried up and disappeared, and with them—specifically in states like Iowa—went habitat for 54 species of birds, 23 species of fish including the endangered Topeka shiner; and natural storage of 1M gallons of floodwater per acre of oxbow wetland.
To restore an oxbow, restoration crews excavate accumulated sediment down to the original level of the stream channel. The restored oxbow is left to fill with water and the banks are seeded with natural vegetation. Once reconstructed and naturally refilled, oxbows:
- Offer an efficient way to rebuild water storage
- Create a habitat for both birds and fish
- Help control flooding
- Provide reliable water sources for livestock
- Remove and sequester 45-90% of nitrates from water runoff
- Create enhanced recreational fishing opportunities
Oxbow restoration provides an economic opportunity for Apex and it’s a natural fit for our already extensive stormwater management business. It’s good for the earth, good for local residents, and good for the bottom line.
The Path to Restoration - Apex Success Story
Since 2017, 14 oxbows have been recreated in communities across Iowa under a partnership between the Nature Conservancy and the Polk Soil and Water Conservation District (SWCD). We helped with one of those (and another one is currently in the works!) Details below:
Client: The Nature Conservancy, via a Wildlife Conservation Society Climate Adaptation Fund grant
Challenge: Provide safe, effective water resource management in a local watershed, which the Nature Conservancy seeks to protect and preserve.
Solution: After the Brenton Arboretum, a 141-acre botanical garden in Iowa was identified as a site where oxbow restoration could lead to significant benefits, our Apex team excavated 3K+ cubic yards of soil from a 400-foot section of an abandoned river channel in this 100% self-performed project. After the oxbow was created, the team seeded the banks to a mix of native wildflowers and grasses before installing straw matting to hold soil and seed in place during the establishment phase.
Results: Our work restored the oxbow which now reduces nutrient levels in the river, establishes wildlife habitats for a variety of species, filters water for improved quality, and helps ensure flood management for the arboretum.
Click here to learn more about our Natural and Culture Resources.