Building a beaver dam

Hello all!

I have a new project that I'm going to be documenting here - it will likely take a few years to get everything worked out so while there won't be daily updates I do plan to do regular updates here.

So what is the project? Well from the title you might have guessed - I'm going to try my hand at building my own beaver dam! Eventually, I plan on building a whole series of beaver dams on my property to create a series of ponds at various sizes.



Why Build a Beaver Dam

You might be wondering why I would want to build a beaver dam when I could just use modern earthen dam building techniques that are often used at permaculture sites.

One big reason for me to try this out is that beaver dams were and are a major component of water storage in the western United States. The land and wildlife here are adapted to this type of water storage. I'm a big fan of working with nature when I can and building my own beaver dams seems like a great way to make my homestead truly be a part of the natural environment. For example, fish can generally get through beaver dams while human made dams tend to block them.

Building my own beaver dams are also very cost effective - I should be able to build them for free! The hardest part is getting the materials I need but I have a nice stockpile of material and can get more fairly easily.

I won't need to bring in any heavy equipment which means much less disturbance to the surrounding land.

Beaver dams are also modular in that they can be expanded easily overtime. I can start by building a relatively small say 2 to 3 foot high dam and then based on lessons learned expand it to about 4 feet high. This lets me experiment and learn without much risk since the dam starts small. I would add that the location I'm building the dam does not face heavy flows so any blowout would be minor. Luckily, beaver dams also tend to slowly blowout unless they are faced with extreme flood events. My site won't have to deal with this - the upstream water catchment area is just too small.

If built correctly beaver dams will last a very long time. According to recent research they can last several hundred years and potentially upwards of a thousand years! This is amazing and it should be possible to replicate the work beavers do. Plus, overtime the beaver dam will just get buried and disappear as the pond fills up with sediment resulting in great fertile flat land.

I also think that beaver dams have another advantage over human dams in that they make the water move and cascade through a wide diversity of paths. This can help oxygenate the water and improve the quality of the water as opposed to the water leaving through a single defined channel. Though beaver dams do tend to have basic spillways but the water will be moving through and over sticks and rocks all of which should help oxygenate the water.

Beaver dam analogues are being used in environmental restoration work and I have constructed a couple for my own restoration projects for my work. But the analogues are not built the way a beaver builds a dam and while effective they don't seem to be as permanent or as effective as beaver dams. My goal is to eventually create a dam that can match one created by a beaver. I also hope that my dam will look just like a beaver dam - I want someone who visits my site to see it and think a beaver built it

So why not just let beavers build their own on my property? One is the lack of control - I want to choose the size and location for each pond based on my needs. Another is that it is just not the type of site a beaver would build at. There is limited building materials (grass field) and the stream is seasonal - not the type they tend to use. That leaves it to me

My property also can't support large scale dams and ponds - I just don't have the space for them. But I can support a series of small and medium sized ponds which I think are a great fit for beaver dams.

Beaver Dam Observations


20 acre beaver pond/wetland that I have been observing

I have been reading studies on beaver dams and observing beaver dams in the wild now for a couple years to get ready for this project. I used to work for an organization that used beavers for environmental restoration and my job was to use Geographic Information System (GIS) modeling to determine areas that were appropriate for beavers to build their dams and ponds.

One observation is that there is a ton of plant material, mud, and rocks mixed in with the sticks. We tend to think of the dams being a collection of wood but beavers transport a ton of sediment too when building their dams. The upstream side of the dam tends to be all mud. This is one reason why you can often find plants growing out of a beaver dam.


The backside of the relatively small beaver dam that created the 20 acre wetland/pond shown in the previous picture. Picture was taken towards the end of an extreme drought that really lowered the water level.

The challenge will be finding the appropriate balance between the different types of material. How often do I need to use wood versus the other material? This is where experimenting comes into play.

Another observation is that most of the material is pushed into place from the upstream side moving downstream. This makes sense because even a small pond makes it easier for a beaver to transport the material - the downstream side is just a stream and would be hard for a beaver to move material in the relatively shallow water and against the current. I think this is important because it will dictate the direction the material is facing. I'm going to do all my placing of material in the same way despite the fact that I could easily work on both sides.

I have also noticed that while beavers will repair their dams often dams are also abandoned and tend to last a long time without any active maintenance. While I expect to need to maintain the dams I'm hopeful that my own beaver dams could be very resilient and not need too much in the way of repairs. Perhaps just a spring repair once the peak flows have passed.

The Building Site


In this picture you can see the main seasonal stream during high flow and a small side stream that enters it just above where I want the first pond to be. The dam and pond will be just downstream from this picture.

My property is 2.86 acres in size and has a gully that runs through the middle of it with a small seasonal stream. The first beaver dam will be built at a spot that is eroding and currently sees a concentration of flows. If I build the dam there (only 2 feet high) it will stop this erosion and create a nice small pond behind it. I can eventually expand the size of the dam both in height and length and turn what becomes a swampy grass area into a great pond and wetland.

Downstream of the first dam site is a wetland area that I have established a bunch of willows. My hope is that the pond will help keep a good water supply for the willows - the area currently dries out a bit in the summer but the willows are still growing.

My plan is to eventually build a whole series of dams to create a series of pools that would step down from one to the next. Each dam would create a pond that would end about 10 to 15 feet in front of the previous dam. This would create ponds, short stream sections and shallow wetland areas. The goal is to get as much diversity of habitat as possible.

Ultimately, I hope that the collecting sediment will start to fill in the gully and create fertile fields in the bottom of it but that is a very long term goal.

In the short term I hope that by creating these ponds I can take what is seasonal stream and end up with year round water on my property. If I can achieve this it will dramatically change my property.

I'm going to start building the first pond tomorrow (Dec 11th, 2018) - I'm taking the day off from work to celebrate the launch of my new online blog/business. I thought building a beaver dam would be a fun way to celebrate! I will post pictures on here showing before construction, in the middle of construction, and the results either tomorrow evening or the next day depending on time.

My plan is to build this first dam and pond and then observe it for the rest of the wet season. I won't build any more until next fall - I really want to be careful and take time to observe and learn.

So what do you all think? Crazy idea? Can it work? Have you seen examples of someone building their own beaver dam before?

I love it!  I think we all need to make like a beaver - Dam It!

You do not describe the actual dam building method...will you start with a loose line of upright pallisade branches/sticks then an angled pallisade as the framework then fill with mud/rock/stick?

Would it not be better to do this as the stream dries, as opposed to now when levels will fluctuate?

Are you working from the outside edges in, towards center?

How wide will base vs height be? A lot of folks underestimate the base width of a beaver dam.

Super cool project! Good luck!!

Lorinne Anderson wrote:You do not describe the actual dam building method...will you start with a loose line of upright pallisade branches/sticks then an angled pallisade as the framework then fill with mud/rock/stick?

Would it not be better to do this as the stream dries, as opposed to now when levels will fluctuate?

Are you working from the outside edges in, towards center?

How wide will base vs height be? A lot of folks underestimate the base width of a beaver dam.

Super cool project! Good luck!!

I will talk about that with my next post. While I have read a lot and observed existing dams I'm not really sure the best way to start. A lot will be trial and error to see how it goes. I will be taking a lot of pics.

My current thoughts are to start by building a mud base with some rocks and plants mixed in. This will give me a substrate to get the first branches and logs pushed into. After that it will just be building with branches n logs and adding more mud, rocks and plant material. Not really sure the needed ratio...

The base will be wider than the height. 2 times as wide as tall give or take.

My soils are heavy clay which means it is really hard to dig when it is dry. The stream is currently just a small trickle but the soils are wet enough that I can actually dig in to get the material built up and I should be able to jam sticks into the ground. It would also be harder to test if there was no water flow.

Good questions!

Good stuff Daron, I have been working on my dams for years now. I am slowly restoring a very old dam system that is fed by a year round spring. I hope to create a larger place for my moose mamas to raise and feed their young.  Looking forward to seeing your work.

Beavers do a lot of excavation to deepen ponds and open channels.  They then pile that mud and soil up onto their dams and lodges.  While I applaud your efforts, you are not a beaver, and you'll find it very difficult to do what they do so effortlessly.  A family of beavers can move a LOT of dirt in a couple of years—hundreds of yards, ultimately.  

It is an interesting idea, but I too think you will find it difficult to emulate beavers. They excavate a lot of soft soil from the floor of their dam once it is submerged, which both deepens the pool and provides building materials. They also do a huge amount of ongoing construction and repair work beneath the surface of the water, shoring up and plugging leaks. If you look at a beaver dam a few seasons after the beavers have moved on, the dam deteriorates fairly rapidly and the water drops. If you want to ensure continued water holding capacity you will need to do continual construction works.

Modern conventional dam building techniques are designed to be durable on a 50+ year time frame without lots of ongoing construction.

In one of the links back in your original post there was the claim that beaver dams last hundreds of years.

Now, that rare map is giving researchers some new insight into just how busy beavers can be. A new survey shows that many of the dams and ponds that Morgan saw nearly 150 years ago are still there—testament to the resilience of the rodents and their ability to maintain structures over many generations.

My emphasis in bold.

They are not static creations. Whole families work tirelessly to maintain them, and they are frequently abandoned when the accessible food runs out, then recolonised a few years later.

It is true that, visable from space, there are some ancient, massive, beaver dams. That said, it is also correct that many dams are only maintained for 3-5 yrs as the tree supply runs out - only to be recolonized at a later date or cyclically.

It may be worthwhile to consider excavating outside the existing water course when building the dam to create deeper areas that could flood in at a later date. It also may be worthwhile sourcing used metal roofing, a rubber membrane, or some such material that could be placed at the water side or in the middle of the dam to facilitate long term maintenance.

A breach down he road could be catastrophic, so do bear that in mind when constructing the dam - one failure upstream could lead to sequential washouts farther down the system and in the blink of an eye years of work could literally be flushed out. With that in mind, you may want to consider installing flood gates that could be opened is water levels got too high, OR a dam looked in peril.

Too control water levels in naturally occurring beaver dams long pipes are often installed that prevent water levels from getting too high. These are often installed to ensure both safety and co-existence with humans and are known as "Beaver Baffles" among other names.

Michael Cox wrote:
Modern conventional dam building techniques are designed to be durable on a 50+ year time frame without lots of ongoing construction.

I agree if one wants a real durable pond the best choice is a properly made earthen dam.  A "beaver dam" is an interesting project which is most likely to result in slowing the water in the channel and allowing silt to build up, in the manner of a brush dam.  Not that there's anything wrong with that, but it isn't a pond, at least not for long, without ongoing maintenance.

https://permies.com/t/51421/Creek-repair-brush-dams

If you don't have beavers, you have to be the beaver.

I like this and look forward to updates. The small size of the creek, the flow, the acreage makes a perfect site for this. I see no cautions or concerns given the layout. Giddyup!

Well the first pond is completed! The pictures are attached at the bottom and show it at the start before I started building and through construction.

At this point it is just a test - an experiment. I want to see how long it holds up without maintenance - while it is true that beaver dams often don't hold up without regular maintenance I have observed ponds at my restoration sites that have had no beaver activity for years and the dams hold up just fine. One of them just recently had beavers move back in and they are now maintaining the existing dam and building it higher. But that dam was not maintained at all for the last couple years and kept a 20 acre pond/wetland. I'm not sure why certain dams fail quickly and some don't - my guess is it depends on size and the flow regime. If the dam is built on a river/stream that sees high seasonal flows I don't think it a beaver dam will hold up without beavers being active.

For my site the flow is fairly minor and is dry a big chunk of the year. But there is already high ground water and an existing wetland just downstream of my property and another just upstream. I think once I get a series of ponds built the lower ones at least should maintain water for a fair bit if not the whole year.

Downstream of my pond is a big wetland and existing pond with a lot of existing vegetation. This makes a great buffer and there is plenty of room for the water to go if my pond suffers a blowout. I also have a bunch of willows planted just downstream of my new pond. They have been stunted due to deer activity but now that the deer are blocked (I finally finished my deer fence) the willows should grow and will help provide another downstream buffer.

I'm expecting it to not hold water as well as I want or as well as a dam built by an actual beaver. But when the water level drops I will use that as a time to build up the earthen part on the upstream side of the dam. I'm also expecting the pond to go dry sometime next year which will let do some more work before the soil drys out.

Assuming the new pond works well I plan to expand it by increasing the width and height of the new dam.

Currently, the deepest part of the new pond is a few inches over my knees. It got deeper than I planned due to the digging I needed to do. But that is really not a bad thing and I'm happy with the result.

Now I just need to observe the pond and the dam and see how it works out. This is a very wet week so the pond/dam is being well tested.

Enjoy the pictures!

Well done! Looks like success to me, and I love that there is some "leakage" so that there is something keeping the build up of water in check.

BRAVO!

Lorinne Anderson wrote:Well done! Looks like success to me, and I love that there is some "leakage" so that there is something keeping the build up of water in check.

BRAVO!

Thank you! It will be interesting to see how it holds up. But I'm happy with the results so far. In addition to the new pond the dam has also resulted in a second stream channel which is spreading the flow of the stream out a fair bit. That should help the willow area a fair bit if it lasts.

Wow, you are one busy beaver!  

I just love this project! I have a couple areas that look similar,  and an even more excited about getting to work on them this spring.  Thanks for posting this.

Thanks Tyler and Trace! It's a fun project lol, I kept wanting to build more once I finished the dam. I still have a fair bit of wood left - there is just so much more water to slow and spread but I'm going to take it slow and observe this one for a while before building more.

For those that have any kind of water flow, using dams gives so much more water retention than swales. Swales are limited to their dugout area.  A dam magnifies that with the water raised upstream. Nice job.

Beautiful dam! I wish I had some areas that were wet enough and flat enough to do that. All I have are well-drained fields and hillsides with deep ravines that need big rock to begin to stabilize them. Oh, and a creek that can move 80 foot white pines right through my property in major floods, and tumble 2-ton rocks if they are not well bedded.

I don't think it will be an issue on your small watershed, but my impression is that many of the sticks in a beaver dam are laid parallel with the water flow, which would resist high flow better than if they were crossways to the flow.

Glenn Herbert wrote:Beautiful dam! I wish I had some areas that were wet enough and flat enough to do that. All I have are well-drained fields and hillsides with deep ravines that need big rock to begin to stabilize them. Oh, and a creek that can move 80 foot white pines right through my property in major floods, and tumble 2-ton rocks if they are not well bedded.

I don't think it will be an issue on your small watershed, but my impression is that many of the sticks in a beaver dam are laid parallel with the water flow, which would resist high flow better than if they were crossways to the flow.

Thanks! I do see the parallel placement a lot in beaver dams but I also see them perpendicular too. I had trouble getting parallel sticks to stay and it seemed like the water would just flow past them and push the soil out so I used a more crossing pattern. Going to keep experimenting with this building technique...

Well one day later and the rains stopped by the evening yesterday and the inflow is much lower. The water level (see attached pic) has dropped a fair bit. From looking at it all this morning it looks like the water is finding a couple paths out of the dam midway down instead of from the top.

I will need to do some patching work and build up soil and vegetation on the upstream side of the dam. The water level got too high yesterday when I was building for me to do this as well as I wanted. There really is too little material on that side of the dam.

Once I build up the upstream side I'm hoping the dam will still leak but at a much slower rate - more from seepage as opposed to flow. Though I'm a bit unsure how to keep the dam from eroding with water flowing over the top of it... Seems like beaver dams handle this fine but I'm still unsure exactly how that works out.

One lesson learned from building this dam is that I got a bit too excited and built up too quickly. I think this is why I have the big leak at the moment. I need to go slower and build it wider from the very start so I can build the earth part as I build up.

Next time I will build a earth/veg/rock base that is as wide as I ultimately want the dam to be. Then I will add wood to it in layers with more earth/veg/rocks and make sure everything is interlocking well. But I will only build up in a slow and methodical manner. That should help to ensure that I don't have to go back in and rebuild the upstream side in the future.

But even with the needed repair the dam is still holding a fair bit of water - a lot more than would have been there without it. For the repair work I'm going to start on the shallow end of the dam that is furthest away from where I was standing when I took the attached pic. This will make this section a bit deeper and let me make sure that end is ready to go. I will then work my way towards the deep part and finish there. Once the leak is mostly blocked and the water level starts increasing again I will call it good for now and just keep observing.

I'm not surprised that it needs a little work. First time ever building something like this so it was very unlikely that it would work perfectly the first time. Looks like it will be wet again later today and through tomorrow morning so I expect the water level to rise soon but then it will be fairly dry for Friday and Saturday which will hopefully give me time on Saturday to finish the repair work.

I will keep posting updates as I make changes / observations.

You are "adjusting" your environment in an ever evolving endeavor - there is no manual and there are no "mistakes" or repairs, this is an experiment that will continually offer lessons for learning and improvements.

 Be proud of your accomplishments after just one, single, day. Learn from the experience, and adjust and share your methods as you learn, just as the beavers do! You can never know what will work until you try, no learning or growth or change occurs until we accept that perfection is an unattainable goal.

Celebrate the small victories, there are no mistakes or failures, simply learning experiences.

Made some adjustments today after work. Spent about an hour adding to the back of the dam. The leaks are greatly reduced and the pond level has increased. More to do but I'm feeling good about the results.

Checked the dam again tonight during a very windy rain storm. The water is flowing over the top in one area but the dam is holding up very well and I don't see any signs of erosion. The pond is back to being completely full too!

So looking good all in all though I still want to add more soil and vegetation to the upstream side of the dam.

I will take a look at it in the morning to see how it held up through the rest of the storm.

It just looks so good - seems to fit right into the landscape.

Posting this because of the similarity.  I used rocks to create a dam which is collecting sediment. I was concerned the erosion will take out the oak tree. This seems to be working. I need to add to it though.

I wonder if the secret ingredient for a good beaver dam is beaver pooh?  Gley makes a pond hold water.  As the level of pooh in the pond rises, it makes sense to me that it would help seal the dam when it was layered on.

South central Alaska is blessed/cursed with millions of bogs.  At the foot of many, if not most of the ones I have examined, is an ancient, abandoned row of rotting wood, dirt and vegetation that is still recognizable as an old beaver dam with a steady stream of water trickling out.

Years ago my son and I wanted to go moose hunting using our canoe (meat hunting on the cheap).  I looked at the map and found what looked like a great little creek, heading into a big bog.  When we actually got there, we found we were having to drag the canoe over abandoned and overgrown beaver dams (8 or 10 feet tall) about every 50 feet.  We ended up changing our plans.  No way could we haul a moose back over all those old dams.

I know it's not beaverish, but it might be a good idea to drive some rows of tall willow stakes into the middle of your dam.  They should sprout and should help anchor things in place and make maintaining it easier.

Tyler Ludens wrote:It just looks so good - seems to fit right into the landscape.

Thanks! This is one thing I love about this method!

Mike - I think that is a good point. But I also think that all the other wildlife that beavers attract from small aquatic critters to birds and larger animals would help with this. I may not have beavers in the pond but hopefully other wildlife will move in and help out with the sealing of the pond. I may also raise ducks in the future so they could help too!

Luckily the location I picked is a place where I know there is very high ground water year round. I think that this will help keep the pond filled if I can keep enough water in the overall system. Once I build more ponds in the future, establish terraces and swales on the uplands, build the organic content of my soil, and get trees established I hope that my land will hold much more water than it does now.

I like that Wayne - thanks for sharing! I'm planning on building some smaller ones like yours in some other locations and I'm thinking about using rocks in between ponds to hold a little water and also increase oxygen levels as the water moves over and through the rocks. So it would go pond -> rocky stream -> pond and then repeat.

Thought I should give you all an update on the beaver dam - there is an updated picture attached to the end of this thread.

I have spent about 4 additional hours working on adding more earth, vegetation and some woody material to the top but mostly upstream side of the dam. In total I have spent about 9 hours building this pond which really is not that bad for its size - and it has not cost me anything other than time. Just used a shovel and wheelbarrow plus some wood that I had already collected for hugel bed projects.

Adding the extra material to the upstream side of the dam was key. There is substantially less water entering the pond but the water level in the pond is higher now than during the initial big rainstorm that first filled it.

I did add 2 spillways - 1 on each edge of the dam. I decided that this option would help keep the top of the dam eroding - plus it splits the original 1 channel stream into 2 smaller channels which further spreads out the water. If I had not put the spillways in the water would have kept rising and then flowed over the top of the dam in 1 or more spots.

I also dug a new stream channel from a ways upstream to split the incoming stream flow so it enters the pond at 2 locations that are spread out from each other. This should also help with circulation of the water in the pond. I have been a bit worried that the end furthest from original stream channel would get stagnant. But now freshwater will flow into that side and with the 2 spillways water will keep moving on both ends of the pond.

I have already noticed some circulation happening within the pond so I think the water will get mixed well.

I have also noticed some water beetles swimming around in the pond - at least two different species. So far no water birds but there was a song bird hopping around on the dam the other day. Hopefully, I will get more wildlife using the pond soon - especially now that it should stay more full.

With the pond being larger now I can easily see a bunch of it from my backdoor which is really fun. If ducks do show up I should be able to see them from my house.

There is a bunch of rain coming over the next few days - over 2 inches on 1 day and an inch or more on several different days. This will be the biggest test for the pond - I hope it holds up well!

I'm just going to go back to observing now - hopefully it won't need any more work for a while. Even if the water level drops a little I'm just going to let it be unless I notice some big leaks.

The pond is staying at the new full level! This morning I woke up to the sunrise reflecting off the pond. Very beautiful!

Edit: do have one new leak to patch. One part at the top where water is flowing. Not really lowering the level of the water but I want to patch it and get the water going through the spillways again and not over the top of the dam. Just a minor little tweak that I need to make before the heavy rains come tonight and tomorrow.

Another update for you all. The big rainstorm has come and gone and the dam has held up fairly well. I did have to go out at the start of the rainstorm and improve the top of the dam - water was flowing over the dam in a couple spots. A few of those had some decent flow and were damaging the dam. But I repaired all of those and built up the top of the dam a bit.

But of course as the water level rises the water would just go over the top again causing more erosion. I ended up expanding the 2 spillways until the water level stopped rising. At the moment this is working great and once the incoming flow slows down the water level should drop until the spillways just barely have water flowing over them.

The pond is really beautiful in the mornings and on clear days. I love seeing the reflections in it and I'm looking forward to one day seeing the moon reflecting in it.

Attached is an updated picture showing the improved dam and spillways and also a couple reflection pictures.

I think the main drawback to this scheme is the difficulty humans generally have of not being able to swim under water for extended periods and (most folks anyway) not having webbed hands with which to push mud around!

Tyler Ludens wrote:I think the main drawback to this scheme is the difficulty humans generally have of not being able to swim under water for extended periods and (most folks anyway) not having webbed hands with which to push mud around!

Ya, that has been a challenge but I have a workaround that seems to be working. Basically, as the dam grows I dig out vegetation/soil from further away from the dam in the shallows. This steadily expands the deeper parts of the pond which is great. But as the water level rises I have to dig further and further away from the dam - this makes it impractical to build the dam too big since I have to carry the material with a shovel and the further away I get from the dam the longer it takes to move the material.

My current plan is to wait for the water level to drop in the summer and assuming the dam holds up fine I'm going to build it up during that time. This way I can dig closer to the dam to save more time. Plus, if I do want to dig from further back I could potentially avoid walking in water which would also make the work faster.

Basically, the plan is to always dig in the shallows and stay out of the deep water

What I love about this method is that I could easily grow the wood I need just from a coppice grove and the soil/vegetation comes from the site. I can get a decent pond for essentially free and even time wise it has not been bad. This project was much faster and easier than my big hugel beds that I also did by hand.

I thought I would give you all another update. There has been several good rain storms here and so far the dam is holding up great. No new repairs have been needed and the expanded spillways are working great.

The spillways make my setup a little different than how a beaver would build but I think it is the best of both worlds. The dam is built as close as I could to the same way a beaver would. But I think one reason beaver dams need a lot of repairs is due to the water during high flow going over the top of a normal beaver dam.

In my setup the high flow goes through the spillways - this is common for human built dams but not beaver dams. I think the spillways will greatly reduce how often I need to repair the dam.

So not exactly the same as a regular beaver dam but it fits my needs well and seems to be holding up very well.

I will post again in a month or so with another update but at this point I just need to observe the dam for a while and see how it does and how long it holds water once the rains stop in late spring or early summer.

Daron, Any updates?  I just love following this project.

Marco Banks wrote:Beavers do a lot of excavation to deepen ponds and open channels.  They then pile that mud and soil up onto their dams and lodges.  While I applaud your efforts, you are not a beaver, and you'll find it very difficult to do what they do so effortlessly.  A family of beavers can move a LOT of dirt in a couple of years—hundreds of yards, ultimately.  

I wanted to give an update to the dam and the pond. So this spring was very dry and the pond went dry back in March. It got a bit more water in it on and off but overall was dry from March until now and it currently is still dry.

This was much too early for my liking. So I spent the summer observing actual beaver dams to see what they looked like and how they were built. I found a couple of brand new but still large dams that helped a lot since there was not much vegetation growing on them.

I also was thinking about some of the feedback I got from you all including what I quoted from Marco. At the end of the day my "beaver dam" was just too skinny. Initially I thought that the sticks were more important then they actually are.

It turns out that the sticks seem to be just for supporting the face of the dam and breaking up the water that flows over it. But the majority of the water holding seems to be from the massive amount of earth and dead vegetation the beavers bring up. All the dams I looked at had a very thick and gently sloping mound of earth on the backside of the dams.

When I was building my dam my shovel was not very effective at getting soil when the pond was full. Then in the summer the pond was dry but the soil was so hard it was not practical to dig in it. So I have been waiting for just enough moisture to make the soil dig-able but not too wet. Over the last weekend I was finally able to do a bunch of digging and improve the dam. Just in time since we have a large amount of rain coming starting Wednesday night!

Attached are 2 pictures that show the new and improved dam. The dam is now much thicker and I'm hoping the extra soil will greatly improve its water holding ability. I'm also going to add more sticks to the face of the dam to improve that part and make it more resilient. Last night I covered the exposed dirt of the dam with wood chips to make sure the fresh soil would hold up to the rains. I have compacted it already but I was nervous the exposed soil would erode if not covered.

I'm going to add fall leaves to the pond in a month or so and also add some large logs to provide habitat for critters.

Overall I would say this dam is inspired by beavers but is of course not a beaver dam. Hopefully it will work much better now. I have plans to enhance the pond behind it next year by expanding the pond, adding a second pond just upstream of it and creating a large island in the middle with 2 small waterfalls on the channels connecting the 2 ponds. Should be a nice place for water birds to hangout and for my family and I to enjoy.

So lessons learned and thank you all for the feedback. I'm happy that the dam held up fine to several winter storms. This makes me feel that the overall design is sound and with the new improvements I think it will hold water much better.

What do you all think? I would love to hear your thoughts and get any feedback you may have. Thanks!

Deepening the pond may also be required, with no constant "inflow", over time the pond will drain into the ground, until the natural water table is reached. Digging a deep hole either nearby or in the center will help with assessing this level as it fluctuates with the seasons and available surface/spring water. If in fact the water table plummets in the dry season, a membrane may be your only permanent solution.

Our water table fluctuates five feet, depending on season. In my neighborhood, in winter you hit water just inches down or even pools on the surface, in low areas. In summer, you have to dig 3-5 feet to hit water (my next door neighbor has a 5ft hand dug well to irrigate their extensive gardens).

You may want to include more than dirt - the Beavers do use rocks, logs, large diameter branches (2-4 inches) etc., not just sticks. But yes, you are correct in widening the dam, most are at least wide enough (2-6 feet) to walk on, once established.

You may want to revisit using used metal roofing, membrane or some other solid barrier to retain and protect the dirt.

Love the updates, keep "beavering" on!

First water today! This is a new little tradition for my family and I. We always watch our seasonal stream and now our pond to see when the water starts flowing again and filling the pond. We call this day "first water".

My son was very excited about the pond filling up and really enjoyed hanging out and playing around the edges of the pond. The improved dam is working great and can easily support us walking around on it.

At the moment there is only a small trickle of water flowing into the pond but the dam is working great and no water was flowing out. At the time of the pictures it was still about 6 inches below the spillways but today is very rainy and the pond should fill up quickly. I'm watching it closely today so I can see how the spillways do after being dry over the summer.

The improvements to the pond seem to be working great. I'm very happy that even a small inflow of water is enough to fill it up and the dam does not seem to be leaking.

The middle of the pond is already dug down below the level of the soil downstream but at this point I'm hitting a layer of gravel that is difficult to dig through. At this point going deeper is not practical but overtime as I build new ponds upstream and enhance the stream channel the overall water holding capacity of the system will expand greatly. I estimate that eventually I will be able to hold a minimum of 50,000 gallons of surface water and potentially up to 100,000 gallons. It all depends on how deep I can make the future ponds and pools. But there should be far more groundwater stored than the surface water. Based on beaver ponds the groundwater holding capacity could be up to 3 times the stored surface water.

Having this much more water stored on my land will really expand what it can support.

I will be digging a couple more pools and remeandering a section of the seasonal stream later this season. These pools will just be dug down so I won't need to build any dams. More on that later!

It looks great!

We have started to get rain again here too. yesterday we got several inches of rain with high wind, and atone point over 1/4 of Maine was without power. Today they are still at 100,000 people without power, including much of Belfast. I live way out in the boonies and the power flickered, but did not go off which was good.

Travis Johnson wrote:It looks great!

We have started to get rain again here too. yesterday we got several inches of rain with high wind, and atone point over 1/4 of Maine was without power. Today they are still at 100,000 people without power, including much of Belfast. I live way out in the boonies and the power flickered, but did not go off which was good.

Thank you! I hope your power stays on!

More rain came since taking the pictures this morning and the seasonal stream got going a fair bit. The pond is now full! I had to do some minor cleanup in the spillways to make sure enough water was flowing out of them that the water level stayed below the top of the dam. There is one spot that needs to be thickened/raised up a bit next summer but it should work fine for now. I mainly want it thicker/higher so I can walk across it more easily and use the dam as a bridge.