Why You Should Give a Dam About Beavers
The beaver (castor canadensis) is the largest rodent living in North America, and one of nature’s most fascinating architects. They are equipped with special tools that allow them incredible construction abilities in places that are otherwise very difficult to work. Beavers work tirelessly to still moving water. The goal is to create a pond with a bunch of ditches that branch off to wherever they wish to go, a little beaver oasis. These rodents are not as agile on land as they are in the water, so more water means safer travels, and underwater entrances into their homes, called dens.
The average weight of a fully grown beaver is around 40 lbs, and they are usually a little over three feet long, including their tails. A semi-aquatic mammal, beavers spend great portions of their lives in the water. They use large paddle-like tails and webbed hind feet to propel themselves through water, making them fantastic swimmers. Beavers are known to slap their flat tails on the water as a warning sign. The sudden sound is loud enough to scare off predators, startle intruders, and alert other beavers of potential danger.
Beavers have extremely large front incisor teeth. The front face of these teeth have a tougher coating than the rear, so as the rear face wears down it creates a very sharp edge, used to chew through solid wood. Their special teeth, and strong swimming ability, allow them to build dams and homes for themselves. Sometimes beavers may tunnel into river banks, but often times they build hut like structures along the shore, or in the water. These master builders are purely functional, heaping piles of sticks and mud in seemingly random places, with no clear entrances or exits. They chew down trees, drag them to the water, and then float them into large piles, filling the gaps to create watertight walls. Beavers will take advantage of natural disasters like hurricanes, tornadoes, and flooding. Any weather event likely to knock down trees near running water means less work for a beaver.
These abilities, as extraordinary as they are, can lead to conflict with another species of great builders, humans. People that farm in low lying areas cannot work flooded fields, and city drainage systems need to remain free of debris and obstruction to function. Unfortunately, beavers are not aware of the wants and needs of people. They remain vigilant in their efforts to make a comfy beaver home. Today, they are quite common, but populations have not always been so plentiful. Unregulated trapping for pelts in late 1800’s severely reduced North American beaver populations. This was remedied by better population management practices, and a decline in demand for beaver pelts. Today beavers can be found all across the continent. In order to coexist with these furry little dam builders, it is important that people understand them, and the methods for dealing with beaver induced drainage issues.
Beaver dams can halt a small creek or drainage ditch, but they can also be quite large, weaving through swamps and wetlands from tree trunk to tree trunk. Large dams like this can become a natural land bridge that other animals may use to stay dry while moving about. Animals like bear, deer, turkey, fox, opossum, raccoon, and bobcats. A family of beavers can construct a dam with astounding speed and efficiency. It is not uncommon for people to work all day to remove a beaver dam, only for it to be rebuilt in a few nights. People that own farms in rural wetland areas may find themselves at risk of crop damage due to flooding from beaver dams. Even damming a small creek, or ditch, can raise the height of a swamp enough to keep water in a field, making it difficult or impossible for heavy equipment like trucks and tractors to work the land. They may cause problems for farmers, developers, and maintenance crews, but the work they do for their respective ecosystems is quite remarkable.
Beavers thrive in rural wetland areas, where human contact is minimal, and wood and water are plentiful. It is important to know that beaver ponds are not just good for the beavers creating them, but can benefit other animals as well. Still or slow moving water is good for biodiversity, creating mini-habitats that shelter plants and animals in the beginning stages of life. A calm pond can also provide animals (that do not prey on beavers) with good hunting grounds.
If you are wondering how how to deal with a beaver dam, or pond, first consider whether the structure is actually threatening any property. If nothing valuable is in danger, beaver ponds can actually provide positive benefits to the local environment. If the structure is a problem, there are some recommendations for removing it, or at least maintaining the water level around the structure.
First assume that, even after removal of beaver constructions, they will likely return to rebuild their work. Also, even if beavers are trapped or relocated, the environment may still attract other beavers. For this there are some preventative measures. Desirable trees can be wrapped near the base with mesh wire, or sheet metal, to prevent beavers from chewing on it. Local wildlife agencies should be able to provide information on what trees and plants are favored by beavers. Removing and not planting these species may also decrease the areas desirability as a home for beavers.
Removing a beaver dam is no easy task, large trees and limbs are packed tightly with mud, but there are ways to do it. Oftentimes a landowner or local wildlife management organization can remove it with machinery or hand tools. A small trench can be dug and pipes can be installed, perpendicularly within the dam, extending far enough out each side so that beavers cannot clog the ends. This allows water to drain despite the obstruction. If the water cannot be kept a desired level for the beavers, they may move to a different place. In extreme cases, where people and equipment may not be able to operate, explosive removal of dams has been used. However, the danger to people and the environment has limited the allowance of such methods.
For well established dams, pipes with grated end covers can be installed perpendicularly within the dam. This allows some control over water levels without removing the entire dam. It is possible that beavers will eventually move away from an area where they cannot control the water level. This method also leaves the dam intact as a natural land bridge for other animals to use.
Sources: Living With Wildlife, Beaver Damage Control