Beaver dam analogue in a small north Missouri stream holding back water and sediment.

USGS researchers at the Missouri Cooperative Fish and Wildlife Research Unit are working with the Missouri Department of Conservation and The Nature Conservancy to determine how beaver-inspired engineering solutions can work in small streams in northern Missouri. Small streams in agricultural landscapes, especially those dominated by row crop practices, tend to become incised over time as erosion eats away at the stream bottom and the banks become steeper and higher. This downcutting of the stream channel can result in unsafe conditions for both people and livestock, cause negative effects on fish and other aquatic organisms, and result in both water and soil leaving the landscape at unnaturally high rates. Although there are engineering solutions that can address these issues, nature’s top engineer, the beaver, can help fix these stream issues at a fraction of the cost. For the study, the team began collecting data on fish communities, plant communities, physical habitat and stream dimensions, and water quality and quantity prior to the installation of beaver dam analogues (BDA). These BDAs are low-cost structures made by driving cedar posts across the stream, weaving other woody vegetation through the posts, and filling the structure with mud and clay to make a dam that will collect soil and may inspire local beaver to adopt them. The team is continuing to collect data after the beaver dam analogues were installed and have already noted changes in the amount of soil accumulated by the dams and hypothesize that given enough time, the dams will raise the stream bed elevation and return the system to a more natural state. The study is located on a demonstration farm, so visual results can be easily shared with landowners to help them decide if this approach is a useful tool to address issues on their land.