Benefits From Beavers
It is clear why people feel a certain amount of angst regarding beavers. A rising pond can threaten infrastructure. If beavers dam a culvert under a road, a piece of the road can be washed away. If they dam a stream that runs beside a dwelling, the rising water could flood the house or cabin. If they build a dam beside an orchard, your fruit trees can be felled. But with a little thought, one can install a cheap, easily constructed 'beaver deceiver' which protects the road or dwelling. And a little wire mesh around the trunk of a tree will protect it. If you keep trying to destroy a dam or kill the beavers, you will have a lifetime job as new beavers move in and start damming all over again. Spend a little time and thought and do it right and do it once. A well designed beaver deceiver will last for decades and allow you to enjoy the myriad benefits that beavers bring. Better still, you only have to do it once. So what are these benefits. They are profound and long lasting.
Beavers don't generally just build one dam. They have their main pond where their lodge and food-store is located, but they tend to build lesser dams up and downstream from the main pond. And because the surface of a water table intersects a stream at its surface, depending on the individual situation, a beaver dam stores far more water in the surrounding land than in the pond(s).
Beavers control floods. When an extreme rain event occurs, the series of dams and the surrounding water table not only store water but also slow down the water. This all contributes to reducing the flood peak and hence, reducing down stream damage. If you have a village that is periodically flooded, you really do want beavers in every stream of your catchment.
Beavers supply water in the summer. Beaver dams are always a bit leaky and as their water goes down, water from the surrounding water table leaks into the stream. Water leaks through the surrounding land on either side of the dam into the next lower stream. This ensures that streams that once went dry each summer, keeps flowing all year round. A good example happened in 1948 in Vancouver, Canada.
In the winter of 47-48 there was an extremely heavy snow pack in the catchment of the Frazer River. Melting didn't start until very late and then the melt came hard and fast. The lower mainland; the Frazer River delta, where lots of farming occurred, was flooded even up to the second floor of some houses. The only creek that didn't contribute to this flood was Meldrum Creek which is located across the river from Williams Lake. More than a decade earlier, Eric Collier (Three Against the Wilderness) had introduced two pair of beaver to the area and they had multiplied and populated the catchment of Meldrum Creek. Incidentally the ranchers further down slope from Eric's operation were delighted because they now had stock water all summer.
Beavers recharge water tables. In fact, close to a beaver pond the water table is raised. Once the water is underground it is protected from evaporation and as it seeps through the ground, it is purified. Another way that water is provided for the summer when streams often have less flow.
Beavers create great fire breaks. Not only are their ponds good fire breaks, themselves, but beavers clear the trees over a few tens of meters on either side of their pond. Now if a fire starts somewhere between two tributaries, it is likely that only that area will burn rather than the whole countryside. Animal that are in the burning section have a refuge in the ponds and in the unburnt area across the stream and in the fulness of time, the burnt area will go through a regenerative succession of plants, creating ecologies that don't exist under a close-canopy forest. Fire now enriches and stabilizes the environment rather than destroying it.
Beavers diversify the environment The areas that the beavers clear of trees on either side of their ponds, now get light right down to the ground which also diversifies the ecology of the area from what used to be only forest. Forage, which was hard to find is now readily available.
Beaver ponds are ideal nurseries for fish. Much of the water is too deep for wading birds and there are lots of hiding places in the submerged parts of beaver dams, beaver lodges, and beaver food stores for small fish to avoid larger fish. And when most species of salmon spawn, they die and their bodies drift downstream. If there are beaver ponds, this rich source of nutrients is caught and incorporated into the pond and even upslope as grazers feed along pond edges and poop upslope. What a great reversal from the general flow of nutrients from the land to the oceans. This enrichment of the pond also feeds their fry who swim downstream from the redds to the ponds and later to the sea. Have a look at an Article titled Rivers Are Life, in the Fall 2026 River Issue of Yukon on Page 27.
Beaver ponds purify the water flowing through them. Their effect of settling out silt and floating twigs, leaves, branches and logs is obvious but they also remove nitrates, phosphates and other 'ates' that are dissolved in the water. The water in a beaver pond is aerobic and under aerobic conditions, a variety of mucro-organisms can use cellulose for energy. More than half of the dry weight of leaves, twigs and branches is cellulose and a beaver pond is full of them. but the micro-organisms need all the 'ates' to build their bodies. They take them from the water (along with aquatic vegetation which does likewise). And of course these two paths of primary production provide food for an extensive food web both in the pond and in the surrounding land.
Beavers protect culverts and bridges. There is an irony for you. We only concentrate on the damming of culverts by beavers which is a problem which is easily fixed. Beavers protect culverts by remove floating trash including logs from the water which each spring tends to be flushed down streams and rivers. This actually protects culverts under roads. In the fulness of time, the floating debris becomes water logged and sinks. Note that if a beaver deceiver is installed to protect a culvert, which beavers otherwise could dam up overnight, the beaver deceiver takes water from the bottom of the pond, where there is no floating debris or ice. Read Building Besides Rivers by Benoit Turcotte from the Fall 2026 Edition of The River Issue of Yukon.
Beavers greatly enrich and stabilize the local ecology. Just read Eric's book (mentioned above) to see the difference that the introduction of beavers into the Meldrum Creek catchment made.
Beavers greatly reduce mosquitoes and biting and non biting midges. Three types of Arctic fish that feed on mosquito larvae are Arctic Greyling, small trout and native minnows. Mosquitoes look for quiet water to lay their eggs and any pond that doesn't have a populations of something that eats mosquito larvae turns into a mosquito beeding farm. The quiet water of a beaver pond is ideal for mosquitoes to lay their eggs. But when they hatch out, as long as the beaver ponds have been there for a while and have any or all of the above mentioned fish, a mosquito larvae does not have a chance. In addition, beaver ponds breed dragon flies which swoop over open water, hoovering up flying insects. Likewise swallows.
Beavers attract tourism. This is especially so if along a walk there are explanations of all the good that beavers do and how to mitigate any harm they may do using beaver deceivers. One could even install a beaver deceiver in one of their minor ponds just to demonstrate the principle along with a plaque showing a diagram and explaining the system. One of the above points could be put on each plaque as people walk the path along a beaver dam complex giving them time to think and discuss. Canadians really do need to be educated about their national animal.
Beavers produce rich bottom land. Over time a beaver pond will fill with sediment and organic material and the beavers may exhaust the supply of nearby trees. (Incidentally, they also eat a large variety of aquatic plants including water lilies and skunk cabbage). The dams then begin to leak and the beaver ponds become a stepped series of beaver meadows. In the fullness of time trees once more start to grow on the banks where the ponds used to be. Another family of beavers will move in and another layer is added. In the long term, this creates the rich, deep 'bottom land' that you read about in western novels.
The problem with our relations with beavers is that the damage they can do is short term and in our face while the benefits are long term and profound and humans are not so good at 'long term'. Just look at our relationship with what we are doing to our environment and our climate. It is up to us that do do 'long term' to try to spread the word to those that do not.
Suggested reading list
Three Against the Wilderness by Eric Collier (of course)
King Fish by David Montgomery (and all his other books. They are eye opening, especially Growing a Revolution)
Pilgrims of the Wild and The Adventures of Sajo and Her Beaver People, both by Grey Owl (AS Belaney - If you can find them. Both from 1935. Would be well worth reprinting)
Beavers: Boreal Ecosystem Engineers by Carol A Johnston (far too expensive to buy. I think there may be a kindle edition available)
Building Beside Rivers from p28 of the fall 2026 issue of Yukon by Benoit Turcotte.