Beavers’ dam building activities can be encouraged in order to help restore degraded river ecosystems. However those same dam building activities can also cause conflict by clogging culverts, flooding roads and infrastructure, and damming irrigation canals. Designing and enacting river restoration projects that work with beaver therefore requires an objective assessment of risk and the knowledge that translocated beaver may not remain at the site of their translocation.
Historically, beaver have been treated as a nuisance. Their dam building activities can cause flooding of infrastructure and clogging of irrigation canals. Perceptions that beaver ponds limit the downstream delivery of water lead the claims that beavers “steal” water that would otherwise be available to downstream users. Land managers hoping to partner with beaver for restoration must address these concerns by identifying the different risks associated with cheap and cheerful restoration projects and the probability and consequences of such occurrences.
Because cheap and cheerful restoration projects are designed and implemented at large spatial scales, and due to the unpredictable responses of translocated beaver, working with adjacent landowners, downstream water users and the local community are essential to achieving restoration goals. Project managers need to be familiar with the effects of beaver on the hydrologic effects of beaver dams and be realistic about both the benefits and potential risks.
In areas where there is the potential for beaver activities to cause damage to infrastructure it is essential to have a plan in place to prevent damage before it occurs. There may be areas that are wholly inappropriate for beaver due to high risk and they may need to be removed immediately and their dams dismantled. There may be other locations where monitoring their activity and using pond levelers or “beaver deceivers” may be able to mitigate adverse impacts and there may also be areas where there is no risk. Identifying these area and having a contingency plan will prevent damage due to unchecked beaver activity. A beaver management plan is also essential for establishing community involement and ensuring cooperation among stakeholders.
There are a number of techniques that restoration managers can use to mitigate the adverse effects of dam building in higher risk areas, while allowing the continued persistence of beaver. These techniques can be used pre-emptively or in response to certain conditions/thresholds outlined in a beaver management plan.
A pond leveler is a simple and low-cost tool that can be used to set the maximum depth and extent of a beaver pond. Resources and a description of how to install a pond leveler can be found here.
A beaver deceiver acts as a scarecrow in order to prevent beaver from building in undesirable areas (e.g., culverts). A description can be found here. Fencing
In order to build dams beaver require building materials - woody vegetation, cobbles and mud. In certain areas felling trees for forage or dam building may present a hazard or be otherwise undesirable. Fencing and painting trees prevents beaver from harvesting ornamental or hazardous trees.