As the largest North America rodent, the American beaver (Castor 

canadensis) can be found everywhere in the United States except the 

Florida peninsula and the desert Southwest. Beaver create their own 

habitat or alter habitats to meet their needs. They create ponds by 

building dams made of sticks, mud, and rocks across small streams. 

These ponds provide valuable aquatic habitats for many species and 

provide beavers with protection from predators. 

Once considered a valuable economic resource for their fur, beaver 

are no longer trapped in signifi cant numbers, which has resulted in a 

growing population throughout the Nation’s watersheds. Today, large 

beaver tend to weigh around 70 pounds. While they do eat some crops 

(corn and soybeans) and aquatic plants, beaver mainly eat the cambium 

layer just under the bark of woody plants. 

While American beaver can produce signifi cant environmental 

benefi ts, they can also create safety hazards and cause signifi cant 

damage. Beaver activity jeopardizes millions of dollars in transportation 

infrastructure and can also cause signifi cant damage to timber resources. 

Alabama alone estimates $19 million in lost timber annually due to 

beaver. 

WS assists in reducing local damage while recognizing and 

respecting the beaver’s importance in the environment.

Damage from Dam Building, Flooding, and Tree Cutting

American beaver are well-known for their dam-building skills. For beaver, 

culverts under highways can provide an engineering shortcut. When 

Protecting People

Protecting Agriculture

Protecting Wildlife

Wildlife Services Factsheet

January 2011

Beaver Damage Management

Wildlife Services (WS), 

a program of the U.S. 

Department of Agriculture’s 

(USDA) Animal and Plant 

Health Inspection Service 

(APHIS), provides Federal 

leadership and expertise 

to resolve wildlife confl icts 

that threaten the Nation’s 

agricultural and natural 

resources, human health and 

safety, and property. 

Recognizing and respecting 

the importance of beaver 

throughout the United States, 

WS assists in reducing local 

damage caused by this large 

native rodent.

By consulting with wildlife 

professionals, individuals can 

help gauge whether a water 

leveling system will be eff ective 

in preventing damage.
beaver build small dams across culverts, they convert 

the highway’s foundation into a dam. These dams 

save the beaver signifi cant time and effort; however, 

most highways are not designed to withstand the 

water’s force, so such conditions can lead to the 

road’s total collapse. 

Flooding from 

beaver ponds can 

cover large areas, 

depriving property 

owners of their use. 

Athletic fi elds, 

yards, croplands, 

timberlands, and 

access roads are 

just some of the 

locations where 

beaver ponds can 

create access and use problems. Utility companies 

often are negatively impacted by beaver pond 

fl ooding, which damages infrastructure and limits 

access to sites. 

Beaver cut down trees for food and for building 

materials. On large trees, beaver will feed by 

removing all the bark within easy reach around the 

tree. This prevents moisture and nutrients from 

moving from roots to leaves and causes the tree to 

die. Other trees are lost due to rising water levels 

behind the beaver dam. Some species of trees can 

thrive in such conditions, but most cannot. When 

beaver remove large numbers of even small trees from 

a shoreline, the result can be erosion of stream banks 

and a rise in water temperature from exposure to 

sunlight. Increased water temperatures can change 

the ecological dynamics of a stream. Additionally, 

fallen trees and beaver ponds can alter the spawning 

of native fi sh. The headwaters of streams can be 

blocked completely, preventing fi sh from reaching 

their traditional spawning grounds. 

Management Techniques

State fi sh and wildlife agencies regulate the legal 

harvest and control of beaver. Some States classify 

beaver as nuisance wildlife, while others classify 

them as furbearers and regulate the seasons and 

methods by which beavers can be harvested. 

To reduce the negative effects of beaver activity, 

WS conducts beaver management as necessary, 

but only at the request of State or local agencies, 

industries, or private groups affected by the damage. 

Exclusion can be a fi rst step to management. 

Wrapping valuable landscape trees and shrubs with 

hardware cloth can prevent loss to beavers. The 

wrapping of plants, however, should be completed 

before beaver arrive. 

Habitat management is another method for 

addressing beaver damage. Such management 

efforts can range from removing trees and other 

woody vegetation that attract beaver, to managing the 

water level of an existing beaver pond. 

Various methods—all of which involve moving 

collected pond water through a beaver’s dam and out 

the other side—can be used to control water levels at 

beaver ponds. By their nature, beaver are very good 

at detecting leaking dams. The sound of running 

water and the current produced by the leak prompt a 

beaver to repair the dam. 

This repair response sometimes can be 

prevented by having multiple intake ports in PVC 

pipe(s) pushed through a dam. Multiple ports reduce 

e.

Beaver can damage single trees or acres of agricultural lands 

and transportation infrastructure.
or eliminate the sensation of current fl ow and the 

associated sound of running water. The outfl ow or 

downstream end of the pipe can be fi tted with a 90 

degree elbow fi tting that can be rotated to raise or 

lower the level of the pond. 

Leveling systems cannot be used in every dampond damage situation. Consulting with wildlife 

professionals can help gauge the potential for 

success.

Beaver Dam Removal

Although they are very sturdy structures, beaver dams 

can be removed through the use of hand tools, heavy 

equipment, or explosives. State wildlife regulations 

may limit or prohibit these techniques so check with 

your State wildlife agency before taking any action. 

WS personnel are trained and certifi ed in the 

safe and effective use of explosives. However, unless 

the beaver are also removed, they will quickly repair 

the dam.

 

Population Control

Beaver can be very persistent once they decide upon 

a dam location. When dam removal or modifi cation 

efforts fail or become impractical, removal of the 

beavers may be the only way to address the problem 

or control damage. Where legal, beaver may be shot 

or trapped. A wide variety of traps are available for 

capturing beaver. Some are designed for live capture, 

and some are lethal devices. 

Many States prohibit the transport and 

relocation of wildlife. The State wildlife agency 

should be consulted before any population control 

methods are attempted. State regulations may limit 

the types of traps, trapping methods, and seasons in 

which beaver may be trapped or shot. 

Additional Information

For more information about WS and managing beaver 

damage, contact

1-866-4USDA-WS (1-866-487-3297) or visit the 

Web site www.aphis.usda.gov/wildlife_damage. 

The U.S. Department of Agriculture is an equal opportunity provider and employer.

Mention of companies or commercial products does not imply recommendation or endorsement by the USDA over others not mentioned. The USDA neither guarantees 

nor warrants the standard of any product mentioned. Product names are mentioned solely to report factually on available data and to provide specifi c information. 

United States Department of Agriculture

Animal and Plant Health Inspection Service

WS biologists are experts in beaver damage 

management, including the removal of dams with hand 

tools or, when appropriate, with explosives.