NC State Extension Publications

 

Once nearly eliminated in North Carolina, beavers have returned to most of the state's watersheds. Beavers are unique in their ability to modify the environment for their own needs by constructing sturdy dams of sticks, leaves, and mud.

Although beavers are viewed negatively in some situations due to damage from the flooding and girdling of trees, their presence may ultimately be beneficial because beavers create wetlands. This publication reviews some of the benefits of beavers and methods to manage and enhance beaver ponds.

photo of beaver lodge on flooded swamp forest in winter

Active beaver lodge

Liessa Bowen  CC BY-NC-SA - 4.0

Photo fo swimming beaver dragging a leafed-tree branch

Beaver at work with dam buildling.

Steve Hillebrand, USFWS  CC BY - 4.0

Beaver Ponds Old and New

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Beavers typically construct a dam or a series of dams to raise water levels to access food sources safely by swimming instead of walking. Most beavers depend on their ponds as places to meet all food and cover requirements. Beaver ponds range in size from less than one acre to well over 100 acres, depending on the topography, the age of the pond, and the availability of food sources. Beavers will use and expand a pond area until the food supplies are exhausted, usually up to 10 years or more.

After abandoning a pond, beavers move into other areas and establish new living sites, leaving the old pond to silt in and eventually return to its original condition as a forested wetland. Beaver ponds provide a wide array of ecological benefits.

Active Pond Benefits

  • Improve downstream water quality by allowing sediment and other pollutants to settle out
  • Supply important breeding areas for amphibians and fish
  • Furnish feeding, brood rearing, and resting areas for waterfowl
  • Create dead trees (snags) for birds, bats, and other mammals

Abandoned Pond Benefits

  • Provide residual snags for cavity-nesting wildlife, as with active ponds
  • Fallen logs supply cover for reptiles and amphibians
  • Supply moist-soil conditions that may continue to provide habitat for waterfowl and other aquatic wildlife
  • Provide foraging and nesting areas for bats, songbirds, owls, hawks, and other wildlife


Beaver pond wildlife.

Active Ponds

Abandoned Ponds

Wood ducks

Mice

Canada geese

White-tailed deer

Amphibians and Reptiles

Black bears

Bats

Wild turkeys

Cavity-nesting birds

Bats

Furbearers (otters, raccoons, beavers, etc)

Cavity-nesting birds


See Houses for Wood Ducks for details on erecting wood duck boxes, and Bats for ways to encourage bats in beaver pond habitats.

photo of beaver swimming toward lodge with only head visible

Beaver swimming near its lodge

Liessa Bowen, Wildlife biologist  CC BY-NC-SA - 4.0

Photo of birdbox erected on edge of ideal wetland habitat

Weltand habitats, including beaver ponds, can be improved by adding a wood duck box.

Liessa Bowen, Wildlife biologist  CC BY-NC-SA - 4.0

Enhancing Beaver Ponds

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Enhance beaver pond benefits by using a drainage system to manage the level of the pond. Inexpensive, effective drainage systems can be built using logs, PVC, or aluminum irrigation pipe. The Clemson Beaver Pond Leveler (Figure 1) can be made with PVC pipe, mesh wire, and an elbow joint. The Clemson Leveler is effective because its intake device is positioned beneath the water and is caged to ensure drainage even if blocked by debris or dam materials. The addition of an elbow and stand pipe allows for easy water level manipulation. However, beware that beavers may respond by damming the area below a leveler, in turn flooding the leveler and the old dam.

Beaver Pond Management

  • Break the dam on the downhill side of the existing channel in the form of a narrow, deep "V." The initial flow of water through the dam will help clear excess dam materials. Place the drain pipe deep into the break so that at least 10 feet of pipe extends into the upstream area. The final level of the pond will be determined by the height of the downstream end of the pipe, or the stand pipe position height.
  • Drive a metal stake into the end of the cage to secure it. The 10-inch drain pipe is perforated with 2-inch holes prior to being encircled by galvanized weldwire fencing.
  • Install more than one drain per dam on larger ponds or to accommodate for high water events.
  • Check beaver pond drains at least once a month to ensure that the desired water levels are maintained. Always leave at least 13 to 12 of the pond area undrained during drawdown, as overdraining may cause the beavers to seek new areas.
  • Drain ponds to a level of 1 to 2 feet annually during the spring and summer to promote natural emergent vegetation and productive moist-soil areas. Flood the moist soil vegetation during November through February when wintering waterfowl are abundant.

Habitat Enhancement Tips

  • Install wood duck boxes, with predator guards, to supply and improve nesting and brooding-rearing cover in beaver ponds.
  • Leave snags and fallen logs for use by birds, reptiles, and amphibians.
  • Avoid use of chemical fertilizers and pesticides near wetland areas.
Figure 1. Clemson Pond Leveler.

Figure 1. Clemson Pond Leveler.

References

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“Clemson Beaver Pond Leveler”: Clemson University, Department of Aquaculture, Fisheries, and Wildlife, AFW Leaflet #1, Dec. 1991.

Beavers. Bromley, P. and others. Wildlife Damage Management, N.C.Cooperative Extension. AG 472-4, Oct. 1994.

Authors

Wildlife Biologist
Professort (Wildlife)
Forestry & Environmental Resources
Extension Professor
Forestry & Environmental Resources

Publication date: July 1, 2019
Revised: June 13, 2019

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North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age, veteran status or disability. In addition, the two Universities welcome all persons without regard to sexual orientation.