Enhancing Rum River shore habitat with revetments

This project is part of a multi-county effort to improve riparian habitat identified during the regional Rum River WRAPS. Water?s edge habitat and erosion control is an important management need for the Rum River. We will use cedar tree revetments to enhance shore habitat and correct erosion on 1,500 linear-feet of mild to moderately eroding riverbank. 40 landowners expressed interest in response to outreach on 1/9th of the river corridor. We will select sites with preference for creating contiguous habitat particularly adjacent to protected land and stabilizing riverbanks that are most likely to worsen if left untreated.

The Rum River is a state designated Wild, Scenic, and Recreational River, state water trail and popular fishery for smallmouth bass, northern pike and walleye. It has been identified as a regional priority by the Isanti, Mille Lacs and Anoka SWCDs. Furthermore, The Nature Conservancy has identified the Rum River as a key area for habitat and water quality, due in part to the fact that is it a headwaters area for the Mississippi River. Protecting the scenic nature of the river and the fishery necessitates repairing shore habitat and erosion.

Bank erosion is prevalent, but much of it is mild or moderate. By applying low-cost ecologically friendly bank stabilization approaches to these sites, we hope to minimize the long-term need for costly armament that is often necessary to correct severe erosion. Cedar tree revetments are ideal because the trees are readily available for little or no cost, they can be planned without extensive engineered designs, installation requires simple hand tools and little specialized expertise, they can be installed in sites inaccessible with large equipment, and the installation results in no collateral site damage or associated restoration cost.

The technique utilizes Eastern Red Cedar trees, which are naturally rot resistant and are considered invasive in prairie landscapes. Cedar trees are anchored along an eroding stream bank. The trees? dense branches create a flexible armor and habitat network for fish and invertebrates. Sediment is often deposited within the revetment, helping to stabilize the toe of the bank and build a suitable area for plants such as sedges to grow. Live willow or dogwood stakes are often added among the cedar trees to accelerate the revegetation process. By the time the revetment trees have decayed in 10+ years, the bank is often stabilized by the roots of the living vegetation.