Let The Beavers Do The Work

City workers were doing their job when they removed a beaver dam from my Kitchener, Ontario neighbourhood in late November. A family of beavers had spent the last six or seven years damming a storm water channel and creating an adjacent wetland. The water had finally risen above the storm water outflow pipe and threatened to block the community’s drainage if the water was to freeze. The city had been monitoring the situation and decided it was time to act. They brought in heavy equipment and removed the dam.

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I’ve spent the last three months exploring this area with my dog. Trails wind through an overgrown field bordering the main Grand River channel on one side and the wetland on the other. It’s an ever changing, water soaked landscape with a novel mix of disturbance tolerant invasive and native plant species. There were three beaver dams that I noticed in the wetland area. Mallards, geese and blue herons also took refuge in the mix of what was shallow cat-tail dominated areas and open water. With very few other visitors, this spot was a rare gem in this urban area.


One November afternoon I took my dog for a hike to the river and found that the beaver dam was gone and the water in the wetland had been drained. This was a very cold week and the water had been frozen over. When the dam was removed and the water drained from under the ice, it left a frozen outline of ice around the trees and cattails. The dramatic change in water levels could be easily seen. In just two days, the water had receded by almost a meter.


My initial feeling was one of personal betrayal since my favourite nature refuge had been completely changed overnight. My thoughts then went to the beavers. First, where had the family gone that had lived in the dam that was removed? Second, how would the others survive with only a muddy couple of inches of water left?


Beavers are fairly ubiquitous in this part of the world and like other species that are considered pests they are grossly undervalued. In this case, water managers perceived the beavers as working against their water management objectives. If the water hadn’t been drained there could have been damage to the infrastructure. This is certainly understandable. But at the same time I can’t help but think about the hard work of the beavers. Consider that just two beavers had built an entire water treatment system that filtered the storm water from my community. Best of all, the water was cleaned without the cost or footprint of a human built water treatment facility.

The water that washes off of our communities can be toxic. This water in particular runs off an industrial area where transport trucks and heavy equipment frequent. Chemicals drip off these vehicles, are mixed with road salts, lawn and home pollutants and wash into storm water drains. Since the dam was removed, these chemicals go directly from the pipe into the Grand River.

The cheapest and most efficient way to clean water is to treat it as close to its source as possible. In this case, the wetland had been cleaning the runoff from my community only a couple of hundred feet from where it falls as rain or snow. The beavers were inadvertently achieving best management practices and water managers failed to recognize this.


Today more than ever we need to recognize this type of opportunity. People in Ontario have removed most of the wetlands over the last hundred years. However, we now understand the benefits that wetlands provide for us and for other organisms. Not only do they filter water but they also reduce flooding and support biodiversity. Huge amounts of money are poured into wetland restoration projects to re-establish these ecosystems.  Imagine the amount of resources that could be saved if we allowed other animals to help us restore our environment.

Over the last couple of weeks the beavers have begun to rebuild their home in the same spot. I imagine when spring arrives the naked stream bank and muddy flowing water that was left by the city workers will evolve into something similar to what it was before the dam was removed. This time, instead of seeing the beaver as working against our goals, we should recognize the habits of these animals as creating an opportunity to restore wetlands in this region and improve the water quality of one of Ontario’s main river systems.


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