CONCEPTUAL DESIGN DETAILS 4

What Is a Beaver dam analog?

Beaver dam analogs are human-constructed dams of woody debris meant to imitate the stream alterations caused by beavers. Sometimes they are built with the intention of attracting beavers, and sometimes humans intend to perform the needed maintenance that would have been provided by a beaver. There are two main types of beaver dam analogs, post-assisted log structures and beaver dam analogs without posts. These structures have many benefits for river systems, including slowing water, encouraging deposition, and increasing channel connection to floodplains and riparian areas (Wheaton, 35).

Post-assisted log structures have structural posts that are driven into the ground with large woody debris woven between them to create the structure. This type of structure is less similar to a beaver dam but is more resilient during floods because the posts driven into the ground help keep them in place (150).

More literal beaver dam analogs are piles of woody debris that fill the entire channel but do not have anything attaching them to the ground. These structures are more likely to change over time (150).

Both structures are filled in with sediment but are still porous and allow water and finer-grained materials to pass through them. Both require maintenance and are likely to change within the channel over time, reflecting the dynamic flow patterns. Beaver dam analogs have become more common in western states like Utah and Idaho, especially in heavily incised channels where beaver recolonization is desired to help slow erosion. Though these structures haven’t yet been adopted in the eastern US, the BeaverCON conference was held in Maryland in 2022, entitled Building Climate Resilience: A Nature-Based Approach that discussed the ecosystem benefits provided by beavers (BeaverCON).