Beavers are second only to humans in their ability to change a landscape. Some of us admire that ability, others aren’t exactly fans. Love them or hate them, beavers may play a huge role in helping us to meet our growing water supply needs in the arid West.
Prior to European settlement, it’s estimated that the U.S. and Canada were home to somewhere between 60-400 million beavers. In the 1700 and 1800s, the popularity of beaver hats in Europe made for a very active beaver trapping industry throughout North America. As the beaver populations in the Eastern U.S. were wiped out, trappers moved westward and set up shop in the Rocky Mountains, making Colorado an important fur trade location by the mid-1830s. But by 1840, the popularity of beaver hats was waning. It was too late for beaver populations, however, which could no longer be found in most of the US. Today, only 10 percent of the viable habitat in Colorado is inhabited by this keystone species, or a species on which other species of the ecosystem depend such that if they were removed, the ecosystem would be drastically changed.
But let’s back up to what it was like prior to fur trappers. What did upwards of 60 million beavers spread across the continent look like? If you are imagining beaver ponds sporadically dotting the river valleys, you need to think bigger.
“Beaver ponds and their dams were like rice paddy terraces going down the stream. When beavers were wiped out, the land dried up. When farmers and ranchers arrived at these dry landscapes, they thought it had always been that way,” explained Ken Neubecker, Colorado Projects Director with American Rivers.
In other words, the arid landscape we call home is due in large part to the loss of healthy beaver populations. The land was much more lush and wet under the management of the beaver. In fact, a study by The Lands Council in Spokane found that a single beaver can store an estimated 10 acre feet of water. To better picture this—one acre foot is roughly the size of a football field covered one foot deep in water. The Sierra Club estimates that it would take 40 million beavers, still well below their historical distribution, to store all of the water that was used in the U.S. in 2010—which includes drinking water, irrigation, agriculture, and industrial uses.
A study completed in 2004 on the Colorado River in Rocky Mountain National Park by Colorado State University and the USGS found that “beaver ponds elevate the water table [or groundwater] during both high and low river flows and slow the decline of the water table during dry months.”
It is no surprise then that the reintroduction of beavers is being recommended by some hydrologists. In areas where beaver reintroductions aren’t practical, hydrologists encourage the building of beaver dam analogs, or human-made beaver dams. Both actual beaver dams and analogs can improve water quality and increase base flows according to Ellen Wohl, an expert on the topic and a geosciences professor at CSU.
In areas where space allows for beavers, but local residents are reluctant to welcome them, education can help. Property owners should understand that their landscaping can be protected by simply wrapping trees with hardware cloth or painting the trunks with sandpaint. Both of these practices are used successfully by the Watershed Council at our restoration projects. Flooding from beaver ponds can be mitigated with a pond leveler, or a piping system that creates a continuous leak from a beaver pond that cannot be dammed by the animal.
It is important to also note that the benefits of beaver ponds go well beyond water storage. Dams improve water quality, capture sediment and reduce erosion. Beavers also create and sustain wetlands, which make up only 5% of land in the contiguous U.S., but provide habitat to more than 1/3 of endangered and threatened animals. Wetlands are home to 31% of plants in the U.S. and experts estimate that as many as half of the North American bird species nest or feed in these important ecosystems. While mosquitos are often associated with beaver ponds, studies have shown that mosquito populations decrease significantly following the development of beaver ponds.
The reintroduction of beavers would provide a number of benefits and could play a leading role in accomplishing the water storage goals of the Colorado Water Plan. Perhaps it is time that state officials and local residents alike seriously consider the role of the beaver in the state’s water portfolio.
Holly Loff is the Executive Director for the Eagle River Watershed Council. The Watershed Council advocates forthe health and conservation of the Upper Colorado and Eagle River basins through research, education, and projects. Contact the Watershed Council at (970) 827-5406 or visit www.erwc.org.