Community Agriculture Alliance: Back to Basics — Natural Engineering for Forest Health
Lately, there has been a lot of talk about water shortages and excess forest fires.
Between current runoff forecasts for the Yampa River basin, projections that suggest the peak fire season will start earlier and last longer, and the dire need to improve forest management statewide, it leaves a lot of people wondering what to do.
How can we help mitigate the risks of ongoing drought and wildlife, and help forests regenerate? Well, an important attribute of healthy forests and their watersheds to consider is the “sponge” effect.
Healthy forests act like a sponge, absorbing moisture, slowing spring runoff seasons, and releasing water over a longer period of time, and one opportunity to enhance this sponge effect is to perform restoration based on low-tech process (LTPBR) and encourage beaver activity.
Although the LTPBR concept has been around for a long time, the use of low-tech stream restoration structures, such as beaver dam analogs (BDAs) and post-assisted log structures (PALS), has gained popularity in recent years due to their efficiency, relative ease of installation and low unit cost.
The idea behind low-tech BDAs and PALs is to slow and spread out water flow, accumulate sediment to fill incised streams, and help prepare the ground for beavers to return to the system. These low-tech structures may only be appropriate in certain contexts; to avoid human conflict with beavers, it is best to implement them on smaller streams and in areas with minimal infrastructure.
By adding structural complexity to streams and re-wetting the sponge, we can see benefits such as resilience to wildfires and drought and improved erosion control and filtration of water following extreme runoff events.
Research on the persistence of beaver-created refuges in the Cameron Peak and East Troublesome burn scars showed that there were 2.7 to 2.9 acres of refuges per beaver dam (for a total of 270 and 1,500 acres, respectively). He also showed that well-connected dam complexes had more reliable refuges than isolated beaver dams.
Beaver activity creates fire resistant areas in the landscape and this resilience is important as climate change continues to bring warmer weather, less snowfall and drier conditions.
From wildfires, runoff carries ash, pollutants, and other debris into streams and rivers, along with the soil that vegetation would ordinarily hold in place. Beaver complexes help filter sediment by slowing the flow of water, and this filtration is crucial to the surrounding ecosystem.
Think of them as the coffee filter you use to brew your morning cup of coffee. This filter gives you a delicious drink to sip without a bite of grounds, right?
In the right setting, LTPBR and the promotion of beaver activity can help prolong runoff, re-wet the soil sponge, and reduce damage from drought and wildfires. This, combined with the relatively low cost of implementation, makes this type of restoration work a good opportunity for our forests and watersheds. If you would like to learn more about LTPBR and how it can be implemented, contact the Steamboat Springs NRCS office at 970-879-3225.
Kaitlyn Vaux works for the USDA’s Natural Resources Conservation Service.