Low-Tech Riverscape Restoration Practices Improve Riparian-Wetland Health

Alden Shallcross, State Lead - Montana/Dakotas Aquatic Habitat Management Program

The BLM Montana/Dakotas core Aquatic Habitat Management (AHM) program consists of three fish biologists, five hydrologists, a water rights specialist, a program lead, and a handful of seasonal technicians. Cumulatively, we oversee the management of ~1,100 miles of perennial stream, 45,400 miles of intermittent/ephemeral stream, and 158,000 acres of riparian-wetland habitat. This includes 807 miles of impaired waterbodies. Following is just one highlight of our 2020 accomplishments.

MCC Volunteers work to restore a creek
Montana Conservation Corps youth help
install BDAs. BLM photo

The Glasgow and Malta field offices have partnered with the National Wildlife Federation (NWF) to restore prairie streams in the Northern Great Plains. The partnership has helped the BLM to achieve related goals and objectives that depend on healthy riparian-wetland and aquatic habitat such as water quantity, water quality, habitat for terrestrial and aquatic species, recreation, wildland fire mitigation, floodwater retention, and drought resilience.

While previous land health assessments indicate that current management is typically maintaining or improving conditions, the consequences of structural starvation (i.e., loss of beaver dams and wood accumulations) associated with historical practices are nearly ubiquitous throughout the region.

This is important for two distinct reasons. First, the absence of beaver dam building activity and wood accumulations results in degraded stream conditions. Second, their absence negatively impacts a stream’s ability to heal itself by impacting the processes that are required to maintain ecologically functional riverscapes. For these reasons, many riverscape segments are operating below their potential and recovery through natural processes alone could take decades to centuries. Meanwhile, the associated resource values will remain impaired or fully unsupported.

Cottonwood Creek
Without beaver dam building
activity to slow water, capture
sediment, and support the growth
of stabilizing riparian-wetland
plants, this stream segment has
incised and no longer supports
many of the historic resource
values. BLM photo

A primary focus of this partnership is to increase the scope of restoration by mimicking, promoting, and sustaining the processes that historically maintained the attributes and resource values of most low-gradient streams throughout the region.

The first projects were completed in 2020, despite challenges associated with the COVID-19 Pandemic. Specifically, the BLM, NWF, Montana Conservation Corps, and Montana Trappers Association installed beaver dam analogs along degraded segments of four streams.

Where water was present, results were apparent almost immediately. After just one day of BDA construction, water that previously rushed down the narrow channel was already spreading onto the surrounding floodplain, drawing leopard frogs out onto newly watered ground.

As team members packed up to leave the site several days into the project installation, they watched from a cutbank as a muskrat wandered downstream and plopped from the bank into a newly formed pool; swimming large circles in open water habitat that was no more than dry ground just the day before.

Outline of how a restoration of a creek develops over time
An example from Goldfarb (2018a) of achieving a self-sustaining condition
where meals of beaver dam analogues (BDAs) mimic beaver dam activity,
and then the maintenance and expansion of beaver dam activity is taken
over by actual beaver, and then they maintain a complex system state.