Tree removal to protect levees

Posted on Jan 23, 2023 by

Over the next few months, you may notice some activity at the locks. Crews will start removing trees from the levees around the locks to preserve the integrity of the earthen levees. Although we love the trees, they pose a danger for long term preservation of the levees.

The levees, or dikes as some people call them, are earthen barriers that are between the actual Fox River and the navigational channels on the lock system. The levees hold back the river current and help support the structure of the locks, but tree roots compromise their structure.

As trees grow, their long roots seek out water in the Fox River and the navigation channels. Once the tree declines and dies, the roots rot and leave voids in the levees which become entry and exit points for water. The wind and wave action in the Fox River gradually increase the voids over years, then soil shifts in the bank creating unstable levees.

This is what happened at the DePere lock in 2019. “We removed several large, rotting root balls from the levee and could clearly see where the voids were making the soil unstable,” said Jeremy Cords, operations director for the Fox Locks. “Water levels on the Fox River change frequently, so we need to find a solution that will preserve the earthen structures for the long term.”

Over the next 3-5 years, crews plan to remove 15-25% of the trees annually from the levees and remove root balls. Once trees are removed, crews will pack the root voids with materials that meet DNR and geotechnical engineering standards.

For any questions concerning this effort, please contact us at info@foxlocks.org.

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