Beaver Library

There is substantial evidence that beaver-related restoration, via beaver translocation and the construction of beaver dam analogues, has the potential to increase the climate resiliency of Washington’s stream and riparian ecosystems (summarized in Table 1). By reducing summer water temperatures, increasing summer flows, and enhancing floodplain habitat, beavers and beaver-related restoration can benefit species of conservation concern, including trout, salmon, and amphibians. In addition, beaver-related restoration can ameliorate the negative impacts of high-flow events, create fire-resistant habitat patches in fire-prone landscapes, and foster heterogeneous mosaics of habitat that enhance the watershed-level biodiversity of aquatic and riparian ecosystems. However, these benefits are only likely to accrue under certain conditions, and there is a gap between our understanding of the aspirational potential of beaver-related restoration (what it can accomplish) and the realized benefits of restoration actions (what it does accomplish).

Engineered leaky barriers are increasingly used as natural flood management methods providing ecosystem and water quality benefits in addition to flood attenuation, complementing hard engineering flood defences. Fieldbased monitoring of a natural flood management site, Wilde Brook in the Corvedale catchment, England (UK) studied the rainfall-runoff relationship for a 5.36 km reach with 105 leaky barriers over two years. Paired pressure transducers were placed upstream and downstream of three channel spanning leaky barriers, allowing evaluation of upstream backwater rise relative to rainfall intensity, storm magnitude, and frequency. By increasing backwater rise, the leaky barriers caused overbank flows, resulting in a reduction in the crosssectional area velocity after the event. The incidence of overbank flow depended on the local stream crosssectional profile, barrier properties, location in the reach, and storm magnitude.

This report reviews published research and unpublished case study information on the effects ofrestoring incised and degraded headwater streams in western states with low-tech processbased restoration methods (LTPBR). LTPBR is a subset of process-based restoration (PBR) that seeks to re-establish natural stream processes by reconnecting incised streams with their floodplains and adjacent wetlands so that more frequent inundation of the floodplain occurs. Projects involve the use of simple, temporary, hand-built wood and rock structures that mimic
natural beaver structures, acting as speed bumps that capture sediments to aggrade the stream. LTPBR approaches are substantially less expensive than form-based stream restoration approaches that employ heavy equipment.i This approach is appealing in part because low project costs enable implementation at a scale that can respond to the extent of floodplain alteration, which is estimated at 45% of headwaters streams in Colorado. ii Negative effects of disconnected floodplains include lower groundwater tables, lower summer base flows,
warmer water temperatures, and substantial loss of riparian habitat.

Beaver are ecosystem engineers capable of converting free-flowing lotic habitats into a series of lentic ponds, thereby enhancing the wetland area of a riverscape. Process-based riverscape restoration using beaver reintroductions and mimicry (beaver dam analogues, BDAs) are increasingly used to restore  functions, the provisioning of services, and improve the resiliency of ecosystems across North America and Europe. Beaver can create breeding habitat for a wide range of species within the highly imperilled class Amphibia by increasing wetland area, increasing emergent vegetation, prolonging wetland hydroperiod, and creating deep ponds.

Reducing nutrient runoff in streams is an important task to reduce algae blooms and associated environmental damage in large waterbodies. Beaver Dam Analogs (WTBDA) are an means to address this problem. These Water Tight Beaver Dam Analogs (WTBDA) present a novel approach to this technique that also aim to restore eroded seasonal creeks to perennial wetlands.

Traditional restoration efforts are barely scratching the surface of what could be restored. Moreover, a disproportionate amount of funds are spent on too few miles of streams and rivers leaving millions of miles of degraded streams neglected. To fill this gap, restoration practitioners are increasingly trying restoration techniques that are more cost?effective, less intensive, and can more practically scale up to the enormous scope of degradation.

We have developed and implemented a simple approach that emulates the ecosystem engineering effects of beaver. This approach is less expensive and disruptive than typical large-scale engineering efforts and has the potential to restore both fish habitat and floodplain vegetation more rapidly than simply revegetating and waiting for the riparian zone to mature.  (Pg 246 – 255)

Artificial beaver dams are a hot restoration strategy, but the projects aren’t always welcome.

Study to gather and produce human dimensions-inclusive, basin-centralized beaver knowledge through an explorative, benefits-maximizing approach to landscape-scale BAR opportunities assessment in the Salinas River.

In this study, we tracked beaver dam distributions and monitored water temperature throughout 34 km of stream for an eight-year period between 2007 and 2014. Our results suggest that creation of natural and/or artificial beaver dams could be used to mitigate the impact of human induced thermal degradation that may threaten sensitive species.

Description of the design process for two types of low-tech structures, post-assisted log structures (PALS) and beaver dam analogues (BDAs).

Low-tech stream restoration gains using beaver dam mimicry gains popularity as an effective fix for ailing waterways in the American West.

The Low-Tech Process Based Restoration of Riverscapes Pocket Guide is an illustrated and condensed version of the Design Manual. The pocket guide is designed to fit in your pocket (4 x 6”) to use as a reference in the field. 2019.

Jeff Burrell with the Wildlife Conservation Society with demonstrates how installing inexpensive woody debris in streams to mimic beaver dams can encourage beaver damming to mitigate the negative effects of  less snow melt summer runoff due to climate change in Montana streams.

The goal of this project is to test whether a restoration method developed and tested in Bridge Creek, Oregon will be suitable for restoring streams like Pataha Creek in southeast Washington.

Idaho rancher, Jay Wilde, and Joe Wheaton from Utah State University use BRAT, beaver restoration assessment tool, and identified good beaver habitat to help restore Birch Creek to year-round stream flow.

Idaho rancher, Jay Wilde, partnered with Anabranch Solutions to build BDAs, and the USFS and Idaho Fish & Game to relocate beavers into Birch Creek to help restore year-round stream flow.

Survey that identifies a need to assess beaver-related restoration projects in western rangelands to increase
awareness, accountability, and to identify gaps in scientific knowledge.

This first webinar in the Association of State Wetland Managers (ASWM) and Bureau of Land Management (BLM) co-hosted six-part webinar series on beaver restoration details how beaver affect the land and the hydrologic impacts from loss of beaver through various hunting, trapping and removal activities. The webinar shared the role that beavers and beaver dam analogs (BDAs) can play in stream restoration.