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Beaver Dams: Friend or Foe?

8/9/21 – Although the low water in the Boundary Waters can make canoeing rivers and streams difficult, it’s not the only hinderance. Beaver dams also pose a significant challenge. However, they are a crucial part of the ecosystem, and, although difficult to get over, they raise the water level of the stream to a canoeable level. Without them, many streams would be impassable. Damaged beaver dams can contribute to low water levels above the beaver dam, exacerbating the already low water due to the current drought in Northern Minnesota. There are many natural factors that contribute to dam breakage and failure, but there are a couple tips and tricks we can follow to minimize our impact.

Beaver dams fail when too much water runs over them. This is often caused when the rim of the dam is broken or pushed down, causing water to flow at a higher rate through one point instead of evenly along the rim. The prevent this, avoid the temptation to cross the dam at a point that is already low. Instead, try to either to over a higher place with a substantial amount of plant matter, as the root masses bind the sticks and mud together. If the dam doesn’t have an area like this, you can place a large stick or log parallel to the rim of the dam to step on and move the canoe over. This evenly distributes weight over a greater area of the dam.

You can then pull the canoe over the dam, usually with a person standing on either side of the gunwales and moving the canoe across. Often, it’s possible to leave gear in the boat while moving it over the dam. However, you don’t want too much weight in the canoe. Therefore, everyone should step out of the canoe at the dam. It’s often most stable to step above the dam, though avoid stepping on the rim and causing a low spot where water can flow through.

Lastly, if planning a trip in an area with many dams and/or low water, try to pack lightly and wear proper footwear. Good footwear often includes close toed shoes that drain easily and you’re okay with getting muddy. This could include close-toed sandals such as keens, water shoes, or an old pair of tennis shoes. Overall, embrace the challenge, and try to appreciate the beaver dams for what they do — raise the water level up high enough so that our beloved streams are navigable.