Early data shows benefits of analog beaver dam effort in stream management at Susquehanna Univ.

​The following post was written by Middle Susquehanna Riverkeeper Association summer intern Jay Schofield. Send a message to Jay via email by clicking here.

Innovative approaches to ecosystem restoration are emerging across the USA, and one standout initiative is the Beaver Dam Analog (BDA) project.

Led by Matt Wilson at Susquehanna University's Freshwater Research Institute in Selinsgrove, Pennsylvania, BDAs are dams made to mimic those made by beavers. These dams are strategically placed along fast-running streams to combat erosion and restore groundwater levels.

​“We’ve got a lot of stormwater runoff that comes in at the edge of Susquehanna’s property upstream, and we wanted to better capture that,” Wilson said. “These dams will slow flow down, and because they’re made of sticks and stones, they will let water pass through the middle during a big storm.”

BDAs are man-made but are specially created to mimic natural beaver dams, which slow water flow and encourage sediment build-up. Each BDA consists of five-foot-long wooden stakes driven into the stream bed with up to three feet extending up out of the streambed., with Layers of large logs and branches are alternated on top. Additional shorter stakes are downstream to prevent scouring.

​The project also uses local invasive species for materials, including the Bradford pear tree and honeysuckle bushes. By using nearby invasive plants the project save resources while also helping to control the local invasive plants.

Using freshly cut down trees and branches also give an elasticity to the dams and increases their lifespan. The leaves on the branches also help to pack in empty space, and when they dry, they mix with sediment from stream flow, further fortifying the dams. 

The primary goal of BDAs is to enhance local ecosystems by stabilizing streambeds and fostering healthier riparian zones. By reducing erosion and raising water levels, BDAs support the local habitats and mitigate environmental degradation caused by rapid water flow and bank collapse due to cross-cutting along the stream. 

Early results from Susquehanna University show promising signs, including reduced erosion and gradual streambed elevation. According to Wilson, who added that these outcomes highlight the structures' potential as a sustainable solution to water management challenges, offering cost-effective methods for restoring and preserving freshwater habitats.

“We get to be involved with something that directly benefits our ecosystem that we’re living in here at Susquehanna,” said Bryanna Schienholz, Susquehanna University class of 2025.

“Actually seeing a permit come to life at my own school is really cool,” added Deanna Phillips, Susquehanna University class of 2023, who interned with DEP this past summer in the permitting department.

The project not only helps the local ecosystem, but also shows how effective the BDA method is and encourages it to be used in other similar restoration projects, according to Wilson.

The project has seen a cumulative accumulation of 20 inches of sediment since it was implemented just more than six months beforehand.

​The cumulative elevation change is 50.23 cm, showing significant overall aggregation across the studied transects, according to Dr. Siobhan Fathel, a professor involved in the project. These measurements were taken from cross sections of the stream located 3 meters upstream and downstream of each dam.

This data suggests that the BDAs are effectively raising the stream bed, which helps connect the floodplain with the channel.

By building up sediment, BDAs can slow down water flow, spread water out onto the floodplain, and enhance the overall health and resilience of the stream ecosystem. All of this data has been collected under the leadership of Dr. Fathel, Dr. Dan Ressler and Wilson, all professors at Susquehanna University. 

"The major takeaway is that we usually expect restoration projects to take years to create a measurable benefit. In our case, we've had a significant decrease in flow trapping literal tons of sediment within the first six months, and all of that for less than $1,000 for the whole project," said Wilson. "The benefits to the stream and watershed as a whole have been far beyond most optimistic expectations."