Today I learned--beaver dams are designed to fail!

This is a beautiful and humble thing, not a criticism.  This video ("https://www.youtube.com/watch?v=OnWJ_qSTZ3g") pointed this out and compared to the Hoover dam or human dams, and it is true, the human dam curves upstream so it is an arch and the water's forces will compress it and make it stronger, just as a stone arch is held in place by gravity.  The beaver's dam on the other hand I've always seen curving along the contour and bowed out in places at least, certainly not bowed in.  It will then eventually break.  And this will create an alteration in the local habitat, to be sure.  I like the beavers' approach better.  Just found this fascinating.

The design follows the goals probably. Although we can't begin to understand the beaver's reasons for doing it the way they do, I'm sure if one explained it to us it would make perfect sense. They are building habitat, we are utilizing a resource. Interesting comparison.

I feel that beaver dams are designed by and for beavers.  I bet beavers are happy with them.

I feel there is no comparison to Hoover Dam or a human dam because these dams are not designed to do the same thing.

Beavers build dams across streams to create a pond where they can build a "beaver lodge" to live in. These ponds provide protection from predators like wolves, coyotes, or mountain lions

https://www.nps.gov/articles/buildabeaverdam.htm

There is a big difference between "designed to fail" and failed because they weren't "designed" to last.

Yes, I’ve probably a better way of wording. It would be “designed to last only a short time”

For me, the problem was using the word "designed".
Beavers don't design a dam. They just build dams.
Whether they are effective, or last long, is as much an accident as anything else.
It's just not a designed action.

Jim Fry wrote:For me, the problem was using the word "designed".  

I think it depends on how narrowly you define "design" - some definitions state that it is a drawing, and I admit I haven't met a beaver who draws. However, there is good evidence that they "plan" and Merriam-Webster defines it as "The meaning of DESIGN is to create, fashion, execute, or construct according to plan"

I've read descriptions of people trying to build beaver "analog dams" and how much harder it is than it looks. I agree with Ezra, that if we understood what the beaver's short and long term goals were, it would make more sense and I totally agree with this:

They are building habitat, we are utilizing a resource. Interesting comparison.

Beavers need ponds to keep them safe and meadows to grow the trees and shrubs to sustain their communities. Holding huge quantities of water doesn't do that any better than holding "just the right amount" of water. I don't think they're building their dams to fail, I think they're building them to slow the water to capture the nutrient rich silt to create better tree-growing ecosystems.

I would say that beavers build dams to use water. Humans build dams to store water. Beaver dams in a sense are a special form of a hugelkultur!

Jay Angler wrote:I would say that beavers build dams to use water. Humans build dams to store water. Beaver dams in a sense are a special form of a hugelkultur!

That is an interesting take on the subject. I never thought of it like that. Someone could write a peer-reviewed journal article because it most likely represents a gap in the literature that hasn't been fully explored. Nature is amazing. Does a human-made dam represent only one function? Capturing and holding water - whatever the drawbacks - for human use? I could imagine that a beaver dam represents several functions that intertwine and are mostly if not all beneficial. We may never discover all of them without observation over several years. Very interesting.

j

Jim Garlits wrote: Someone could write a peer-reviewed journal article because it most likely represents a gap in the literature that hasn't been fully explored. Nature is amazing.

Someone has done a great job of pulling a lot of information together. A fellow named Ben Goldfarb. One of our permies, Roberto Pokachinni, recommended his book and it is a delight to read:
Eager: the surprising, secret life of beavers and why they matter
https://www.bengoldfarb.com/eager

I really recommend that people read this if they want to help the land. The Beaver people can do positively incredible things to hold water on the land, and repair much of the damage that humans have done. Yes, they can be annoying when they flood roads, but there are ways to coexist if we just made the effort to do so.

Couldn't resist:

I found it kind of annoying how the Texas guy from the grant org got asked about introducing beavers to the area since a lot of the viewers would want to know the answer, he makes a face and says "that's not happening here. What we're trying to do is mimic what they do" not really addressing why they don't want to introduce them, then the female who works with him coyly says "they are a keystone species that set's things up for a lot of other life" or something like that. It felt like she liked the idea of beavers in the area but could tell how against it he was.

I want to see the Texas guy get naked and start chewing down trees and making a dam with them. If he really wants to mimic what beavers do.

j

George Booth wrote:I found it kind of annoying how the Texas guy from the grant org got asked about introducing beavers to the area since a lot of the viewers would want to know the answer, he makes a face and says "that's not happening here. What we're trying to do is mimic what they do" not really addressing why they don't want to introduce them, then the female who works with him coyly says "they are a keystone species that set's things up for a lot of other life" or something like that. It felt like she liked the idea of beavers in the area but could tell how against it he was.

Here you can see a very old dam which doesn't yet have trees, but is covered in bee-friendly flowers:


source

The longest known Beaver dam is 1/2 a mile long: https://e360.yale.edu/features/worlds-largest-beaver-dam
It's in Wood Buffalo National Park in Canada

Here's another picture of an older dam starting to grow forbs and grasses. These dams build soil and create ecosystems, whereas most human dams don't.


source

Beavers will gradually move into an area on their own if there are sufficient trees of the right variety to support them. The posted video did not show any habitat that I would have said was ready for beavers. It would have been better to have said more about that more clearly. Relocating beavers to a place that will starve them to death isn't the solution.

Jay Angler wrote:Here you can see a very old dam which doesn't yet have trees, but is covered in bee-friendly flowers:


source

The longest known Beaver dam is 1/2 a mile long: https://e360.yale.edu/features/worlds-largest-beaver-dam
It's in Wood Buffalo National Park in Canada

Here's another picture of an older dam starting to grow forbs and grasses. These dams build soil and create ecosystems, whereas most human dams don't.


source

Beavers will gradually move into an area on their own if there are sufficient trees of the right variety to support them. The posted video did not show any habitat that I would have said was ready for beavers. It would have been better to have said more about that more clearly. Relocating beavers to a place that will starve them to death isn't the solution.

I'm pretty sure if the goal was to introduce beavers they'd use a different strategy then just releasing them in an unfit area. Such as planting trees they would enjoy and eventually introducing them. If it's too dry then I'd assume the correct location would be further up valley where eventually they could start pooling water that would lead to down valley eventually being wetter. My point is that he got asked a direct question and didn't give a good answer, perhaps he has a bunch of good reasons but he provided 0 of them.

Just the other day, the “beaver cycle” became apparent to me.  Beavers move into an area, drop trees, build dams, reproduce and live out their lives.  Once all the trees are gone, they move on.  Without maintenance, their dams break down, drain the area and allow trees to grow in the fertile sediment captured by their dams.  After the trees grow enough to satisfy their needs, they move back in and repeat the cycle.

You might find this interesting…

https://www.beaverinstitute.org/why-give-a-damn-biodiversity/#:~:text=Eventually%20successional%20shrubs%20and%20trees,successional%20habitats%20that%20support%20biodiversity.

I just read this article

https://gsas.harvard.edu/news/dammed-if-they-do

about beavers after wanting to learn more which was inspired by some beavers in the Czech Republic recently building a dam somewhere that government officials and engineers were already planning to do the same. The beavers did a great job and saved everyone so much time and money. I want to know how they know the perfect place to build, and how they identify the environment that needs them.