I haven't heard the term puddling clay since I was doing research on primitive building methods and found a site on post and wattle walls. I wonder if the clay they use is the kind you are planning to use? Most of what you will find on this forum, at least, will be references to bentonite liners, certainly a well documented material. I just haven't see a discussion about it here for some time. It is commonly used to seal artisian wells so you could expect such a flexable and absorbant material to fit your drain just fine (if a bit sticky). As for the edge drying out, there would be some wicking but bentonite needs to be wet to work. I don't understand what you mean when you say "other than when the pond is in use". What am I missing?Sandy

Sandy,

Thank you for the response. I have been looking into bentonite also, it does appear to be the best way to go. I guess I'm a bit more organic than I really need to be, although bentonite is just as organic as any other clay.

This pond will be for swimming. What I meant by "when it's in use" is that the only time there will be little waves lapping at the edge will be when someone is in the pond swimming.

By golly, it seems I have puddled clay myself when I was wedging clay for ceramics. I did a google search out of curiosity and found a few sites I will follow up on. Sandy

Here is a link that might be useful: How to puddle clay

Puddled clay was used to line hundreds of miles of nineteenth century canals and some stretches are still wet. There is much information out there on canal construction. BTW, there is nothing organic about clay as far as I know.

Yes there is a lot of information on the net about what puddling clay is. I found a written description on how to finish the edge of a puddled clay pond but I don't understand it. Puddled clay must remain wet, if it dries it will crack and leak. My concern is how to treat the top edge of my pond to ensure it stays wet.

It was used to line canals and is still used to build dew ponds in England. I have been very curious about building a dew pond and may try a small one to see if it will work in my area. Northern Virginia may be humid enough to work in the summer.

This is such an interesting topic. There are all sorts of relationships of materials that I was familiar with and didn't know I knew because I didn't know the name someone else used. When I dug my current pond I had a problem with the walls being unstable. It turned out that the location had been filled in several times with different materials. When I was a kid I learned how to use adobe for finishing a wall and making it waterproof and I decided to finish the sides with a layer of adobe before putting in the liner. It worked like a charm. The walls, once the adobe had cured, stayed in place even though the sides were vertical. LOL!Can you say, puddling clay?
Cured does not mean dry. Cured means the clay has lost plasticity and feels like leather.
Since I did not want to completely dry the clay liner because it would become brittle or could crack and allow ground water to seep in and create "hippos" under the rubber liner, I kept it moist by draping an old cotton sheet over it and sprayed it with a garden hose with a mist attachment as often as necessary. This is how a potter keeps his clay moist and flexable. Once I had the shape of the pond as I wanted it, I put in the rubber liner after the "adobe" got one last misting so it would remain in a plastic form that will absorb water but would be stiff enough to stay in place.
Problems I ran into were surprisingly few. The most common was when the clay adobe dryed too quickly, it had a tendency to crack. This could be repaired easily by applying a very wet clay paste to the sides of the crack. After the edges of the crack and the paste got to the same consistancy, I filled the crack with the same clay I was spreading on the rest of the pond walls with a bit more water added. As the patch cured, it would shrink and I would add some more clay after misting the patch so it and the new clay were of similar consistancy.
I'm getting nervous that I'm going to lose this so I'll save it and continue in another post. Sandy

Here is a link that might be useful: A cutaway of a dew pond with edge

Sandy,

Glad to hear I got your heart rate up over a bunch of mud (-:

Green skinnydipper, you have no idea. I lived in an earthshelter house for 20 years and had a very sticky relationship with bentonite which sometimes worked and sometimes didn't until I got the hang of it. DH grumbles that I never got over mud pies and he may be more right than he knows. I was the only 6 year old in our neighborhood who knew how to lay brick but I wasn't happy that there were no second chances with fired brick and mortar which led to a summer learning the Hopi method of adobe finishing, which led to ceramics and a great tension tamer, wedging clay. I've been able to play around with cob and tamped earth and several other methods of building with clay much to DH's dismay. I married an accountant, who knew? Now I am learning more about sculpting with cement while my poor back heals. The titanium bolts holding my spine together set off metal detectors so I have to avoid airports these days.
If you are interested in such things as preparing the clay for use, how much, how long and how to apply it I'll be glad to pass the info on to you. Who knows? I may even be able to supply some source material if it wasn't lost in a move. The learning curve can be fairly intense especially if you have helpers that you have to teach as you are learning. I learned recently that I am a lousy contractor.
Since you are in Virginia, I would not be surprised if there was an Earthship program near you that you might want to check out. They are mostly into structural work for homes but often do other projects and workshops as well. Was the second link helpful with the cut away? I think if I was finishing that edge I would use concrete pavers on top of plastic or preferably EPDM since it would not let the pavers slip as easily and would keep that edge from disintegrating. Sandy

The link was very helpful. I had run across that site but for some reason didn't study the drawing section very closely. I am thinking that if I create a small berm protected on all sides with EPDM that the water will wick up under the EPDM and keep it moist and prevent cracking.

I would like to use Wisconsin Bentonite as the clay but have not found a place to buy it yet. There are several herbal cosmetic suppliers that sell it in "bulk" but it's right around $5 per pound. Shoot, I can but Wal-Mart brand cat litter (also bentonite) for a lot less than that. I have a contact at a geothermal company that is looking for me. He uses bentonite to seal the top of his wells.

After I slept on it, I began to get nervous about that EPDM covered edge with no wicking to drain too much water. Does that sound silly? I began thinking that if the edge couldn't drain it would become saturated and begin to disolve with persistant lapping. I know there must be an answer already found since there are so many bentonite lined ponds. In fact I started remembering some of the many earth lined ponds I have seen and it occurs to me that while I have seen many, I can't remember any that didn't have a somewhat large berm a foot or more above water level. Do you expect to have rainwater runoff draining into the pond? I didn't know there was bentonite mining in Wisconsin. I thought most of it was in Wyoming or Montana. Sandy

Sandy,

Here is a link to the best information I have found about puddling clay for a pond.

I don't understand the capillary barrier. Do you?

Here is a link that might be useful: Puddling Clay

Wow, reading anything in the idiom of another country is not easy, but to do it when someone is trying to explain something vaguely technical to someone who is not a techniphile makes my brain feel like it's been through a blender. When I was reading the first part I saw a couple of things that made me uncomfortable. Then a point or two in the response seemed off as well. Be glad this is not your pond. It will have nothing but problems. I suspect that the real solution for them is to rip out the whole thing and start over.
Please bear with me for a paragraph or two. Perhaps you remember me mentioning 'wedging clay'. This is a method of driving out air in a lump of clay while causing moisture to disburse evenly throughout the body of the clay. The way this is done is to face a concrete wall and floor section that is covered by a clean non-porus plastic tarp. A lump of clay is slammed against the floor then peeled up and sliced into sections by drawing it over a cutting wire repeatedly until the texture is even and smooth, no air or water bubbles are visible and moisture is evenly distributed. If the clay is too dry, add water by dipping pieces into a bucket of clean water and smashing the chunks together. Resume slamming the clay against the floor and cutting it over the wire. Store the finished clay in a plastic lined container. Cover the clay with a damp not dripping cloth. Mist the cloth daily to keep it moist. If you look at a piece of finished clay after slicing it over the wire again you can see that it now shows even, parallel structure lines that make the clay stronger and more flexable. This is the same thing as puddling except that while here you are slamming the clay against a hard surface when you puddle clay you are slamming a hard surface against the clay. Since the clay is now a similar texture, density and moisture it will adhere, one piece to another, better and introduction of air and water bubbles which weaken the structure is not as likely.
When drying a piece (or section) of clay it must be done slowly and evenly to avoid cracking. This means the core must begin drying first and additional layers of clay allowed to dry somewhat as more layers are added. Edges of any construct must be covered by moist cloth to prevent them becoming brittle before the rest of the piece is dried.

When constructing the pond the clay should be laid in layers that should not be more than three inches thick and the total thickness should be at least 8 inches. Walls cannot be vertical as they will not support their own weight and will crack. I think this was mentioned in the link and is very important. My adobe was less picky as the eventual thickness was never more than 4-5 inches and I staggered the sides with shelves.
Now, FINALLY, I get to the capillary barrier. What he is describing is the way a splice is made in two pieces of EPDM to avoid capillary action that can cause serious leaks. It is also the way flat felled seams are sewn in a shirt to make them stronger. By using this surface that bends back upon itself, twice, forming a W shaped topography separated by a continuous run of plastic, it forms a barrier which ends the capillary action that would pull moisture from the clay into the surrounding soil and limits the amount of water drawn up from the pond. Augggh! My poor brain is getting too old to be this squirrelly! I need to take a break. I'll see if I screwed it up tomorrow. Sandy

Hi guys, I'd like to share some of my thoughts on this.

Because clay is comprised of microscopic particles and pore spaces, it saturates/supersaturates and then dries faster than coarser grained materials. The mud puddle we've all seen. I don't think the structure can really be changed no matter how much stomping and tamping--clay still saturates and dries when water is added or taken away.

I'm a little shaky on this, but it seems clay always underwater stays supersaturated and its consistence becomes more fluid--it creeps downward on the pond walls and helps form the delightful ooze on the bottom. And the brownish cast to the pond water.

The capillary barrier is like a relief valve because it allows for what we usually call wicking on the Forum, simple capillary action. Water in the clay is wicked into a coarser layer that can absorb more water. Then a less pervious cap layer absorbs the moisture more slowly and gets rid of it through evapotranspiration. Some water also probably infiltrates toward the ground water through the bottom.

The hydrologic cycle - water goes into the atmosphere, returns to the pond while the clay remains a bit more stable. In a natural pond with water flow, clay particles won't settle much but are washed out to be replaced by the infinite volume of clay in the surrounding horizon.

My 2-cents guess is that in the long run--1 year, 10 years, 100 years? the relatively thin puddled layer will creep to the bottom and the water holding pond "liner" will be gone without some help.

Just a home-grown observation based on some observations over the years. Look forward to learning more--as Sandy said, an interesting topic.

Mike

Hey there, Mike, I'm glad to have another voice on this. I wonder though if you have ever worked with(or played with) clay. Think about it. Structures of pounded or puddled clay are still standing that are centuries old. While many of those are in desert locations, clay has been used all over the world as a waterproofing material. Natural deposits of clay are laid down in layers with a parallel structure that is sometimes disturbed by roots, burrowing animals and insects, silt, stones or air bubbles. These are referred to as inclusions. Inclusions are removed from processed dried clay by a sifting process. As clay is mined it can come up in layers that must be restored when applied as a waterproofing material. Clay is usually dried to reduce the amount of shipping costs. This further destroys the molecular structure and adhesion of the clay particles but when water is added and the clay is pounded, the parallel structure is restored and the waterproofing ability of the clay works again. As recorded in the bible, sometimes materials such as straw are added as a binding material in small articles such as bricks which are air dried (or fired in a kiln). A brick that has particles that do not conform to the parallel structure will crumble. The amount of water added during the manufacturing process is vital. Too little water means the brick will crumble while too much water remains in the brick as an inclusion which prevents the clay layers from adhering to each other. Making bricks was and is a skilled occupation. These methods are still in use in many parts of the world.
Different clays absorb different amounts of water. Bentonite clay will absorb up to 5 times it's own volume which makes it expand. A lot. That's why it is used to seal abandoned wells, artesian wells, around joints in water mains, etc. The water, even under pressure can't get through if the clay was applied correctly.
Obviously, method does make a difference.
When a potter is preparing clay, it is important that moisture and any inclusions such as a slug of a different clay must be evenly distributed throughout the material or the eventual structure can explode in the kiln. Overworking can also disturb the molecular structure and cause the material to explode. The potter can tell by the feel and the appearance of the clay by slicing it with a wire and observing the inner structure of the clay.
Unfired clay is not as permanently impervious as fired clay but it can be enormously durable. Sleepless

Here is a link that might be useful: clay lined ponds for English school children

Hi Sandy - you have some great information and interesting experiences that benefit my thinking here.

No, I haven't played with clay in the sense of making anything from it. But I agree with what you say for the most part - and basically we only have some semantic or technical term differences I think.

Do you think making pottery or a dwelling or whatever is the same as puddling clay that remains underwater? You can glaze a pot, put binder in adobe, augment the clay and change its circumstance or character. My thought was that if the clay is underwater a different approach to stability and longevity is required. No doubt in my mind that the puddling process changes (or maybe creates a new)structure that makes it tight and really impervious.

My experience with clay is different from yours and mostly from an "underwater" perspective. Early in this thread I mentioned canals. I am a retired archeologist who did a little analysis of poorly fired prehistoric period pottery but spent most of my career studying industrial sites of various kinds - hydropowered. I sliced and diced lots of canals, raceways, dry docks, etc. Most were abandoned and hadn't had any water for at least 50 years. Analyzing the puddled clay was never a priority in the contracts, but I was intrigued to at least compare what I observed with the original plans for the features. No great insights to offer here other than the fact that they still held water when uncovered and tested and the structure had turned from massive to platy--dense chunks to layers as you describe.

I still operate a soil testing lab that deals mostly with making a suspension of a soil and measuring the sand/silt/clay percentages. I have some observations about clay's behavior, the most memorable of which is that when I handle clay it sucks the moisture out of my hands and leaves my skin very dry. Thoughts about that wicking led to my guessing about the capillary layer as recommended in the one link and what I have seen at some landfills.

It is true that sometimes a little knowledge leads to the wrong conclusions. So I find this thread and especially your comments from good experience interesting and informative.

Looking forward to more thoughts and learning and hope some others jump in as well with their experiences with clay and puddled clay.

Mike

Ah, Mike. I wish I had the opportunity to see some of the things you have had the chance to see. What a wonderful time you must have had. At least, I hope so.
A great deal of the knowledge I have is that of a craftsman or artisan who is often more curious about the why and how of something than the what and when. As a result I sometimes am startled at the different ways people can interpret what they see or are told. A case in point: an older sister was trying to use a propane torch to attach findings to jewelry when I dropped in to see her. She is a good bit older than I am and has several degrees and frequently takes classes on the side to fill in the info she gets in her history classes which is why she was melting 18K gold wire all over the work bench. On the other hand I haven't had the chance to take many credit courses for one reason or another but I have made jewelry (although I don't use 18K gold wire) and I have some experience in welding. Once I got her attention, I was able to show her that the torch stays in the holder that came with her welding kit and you move the metal into the flame rather than the other way around or you can just use a soldering gun. She changed her method, finished the jewelry, and we recovered some of the spatters of gold off of the wood work bench. She had her DH pick up a stone slab that didn't hold on to the metal and everyone was happy but me because I kept getting asked how I knew that? It was uncomfortable telling her she needed to do an apprenticeship or take a baby level class to learn some of the basics of working with metals before she burned up $100+ of gold.
She had all the instructions and thought all she needed to know was in them. I knew the professor and he knew I knew what I was doing and had assumed she did as well. She didn't know enough to know she didn't know what I knew so it was an expensive lesson.
I think it might be the same way with clay and the gap between knowing what the result was and the how of getting there. Some of the links I googled mentioned that the canal (or other structure) had to remain wet or the walls would be seriously damaged as they dried and it would be difficult to repair them. Some links said nothing about that. A couple of the links referred to sections of canal that were still undamaged after many decades of not being used. The ones I was most interested in were the links that referred to covering the top edges to prevent drying since that is the question Green skinnydipper is concerned with. What I have not seen in any of the links is the fact that after some clays have acquired a certain degree of moisture they will retain that moisture and shape long after the surrounding soil has dried considerably. From sad experience I can tell you it is very annoying to step where you think the ground is solid, only to sink into a huge glob of saturated bentonite under a half inch of dry dirt. Is clay for ceramics and adobe the same as puddled clay? No, it certainly is not the same. Ceramics clay and adobe clay are designed to work dry and clay to be puddled is designed to be used wet or at the least, a good bit softer than leather hard. While I want my ceramics to become leather hard, I would be very nervous if puddled clay got that hard because it would begin breaking down because it's shrinkage limits are much different than terracotta or other ceramic clays. That top rim we are concerned with needs to wrap over the top and a protective material laid on top of it. Most of the sites I looked at showed older dew ponds had cut, dried, long stemmed grasses or straw laid on top. These could dry out considerably before the moisture began to dry in the clay edge. It would also hold moisture longer than many soils around it as it rotted. It is also a material that could be replaced easily and that could be covered with a layer of dirt to hold it in place.
Many of the ponds built out of bentonite are a mix of bentonite and other clays. The material is shipped in big rolls and does not require the extensive labor that puddling requires. In a manner of speaking, it is already puddled. The rolls are uncoiled and overlapped and those joints are sealed together by pounding with a tamper after being wet down so the two layers can meld. Some companies say the entire surface should be tamped but the joints require more. This makes sense to me. I'm going to see if I can find some of those sites after all this time. There was a company in England that had some lovely pictures.
Something that might interest you is that the surface of tamped clay or worked ceramic clay will become shiny where the moisture has been forced from the surface. This indicates the clay molecules are binding together with more adhesion than clay that has simply been allowed to rest to form layers. That mud puddle you mentioned will form only one layer of clay after a rain. It requires many flooding rains that carry away silt and many dry spells before it can be considered a clay deposit. Sandy

It is Wyoming Bentonite, must have had my head screwed on backward when I said Wisconsin =).

I think getting my soil tested is the next step. From what I understand (thank you Virginia Tech)my soil more than likely has enough clay (more than 10%) to work well when mixed with 1 pound of bentonite per square foot.

I plan to use a walk behind vibratory roller for the "puddling", adding the bentonite/soil mix in three inch lifts with a final thickness of about twelve inches.

I am still researching the best way to penetrate the clay for the bottom drain. My most recent thought is corrugated non-perforated ABS pipe. The corrugation should produce more surface area contact with the clay and provide a capillary break.

Sandy and Mike,

Please keep the conversations going! I find your questions back and forth very informational. Thank you both.

I certainly did have fun--interesting and dull places, people and things. Better than working for a living. A site is a 3D research document that is destroyed while using. A part of studying along with conventional documents and interviews. The old 5 W's--who, what, where, when, why apply--the limit is the imagination or sometimes the contract you work under. Preservation goals.

Some of my canal projects involved observing big machines cut through for maybe sewer pipes. I observed, measured, touched, smelled what I could, played with 1920s junk thrown in when they were filled. I was interested in puddling clay from the outset and basically compared what was there with original construction documents. The bottom was dried out into layers but still held most water up as some leaked out when the cut was opened. Another story.

Off-topic I guess. Canals were dynamic--not only traffic moving but water flowing like a little river much of the time at locks, overflows, and inlets where water supply was replenished. The navigation season in the northeast was relatively short, so the canals were closed and maintenance work undertaken including repair of liners. I don't recall any details now and my old reports are in storage. But obviously the puddled clay was subject to disturbance and able to be repaired.

As you noted Sandy, existing blocked off remnants still hold water. All the canals I looked at were built in glacial soils, which have plenty of clay and other dense horizons--did that help? I don't know.

I will respond more later and promise to be more on topic--clay, uses of clay, lost technologies.

Hope this is OK - Mike

I have always found the five W's to be very helpful but somehow lacking since they don't include the "how" of whatever you are investigating.

It is interesting that so-called treasure hunters locate many of their ship wrecks by studying old shipping records and insurance payouts. I'm glad their occupation has a lot of legal oversight and that they must have an archeologist to check out the site before they can do any recovery.
It has always seemed a real shame that so many sites must be filled back in once research has been done and that others will be destroyed by new buildings etc. I suppose though that it would be rather strange to have the evidence of an ancient battleground, cities, etc. exposed to the elements. The site wouldn't last very long that way. I would hate to be a builder in Rome or London. It could be difficult in many locations. It must be terrible to an archeologist to lose a site to construction, knowing only a small part had been studied before it was covered by concrete.

Living in Wisconsin was an education when it comes to glacial moraine. It seems that more than half the state is comprised of the debris of glacial activity. It has got to be the most illogical mix of soils, rocks and boulders and hills and holes in the terrain that could be imagined. The other half is protected because of antropological evidence of ancient people. Often both exist in the same place. It is a great place to live if you are in one of the "-ologies" or fascinated by them as I seem to be. Our first house there was on the edge of a deep ravine containing some really big rocks. It had started out as a deep deposit of ice and debris, then it eroded into a small valley where even more boulders were deposited.

The next house was an earthshelter built into a hillside below a huge meadow. Some of the boulders there were the size of a car. It was no small task to move them out of the way of the house and diveways. The back of the lot was defined by an 80 year old logging road and there was a large rock with carving in it that seemed to be a boundry marker of some sort. The house had a huge swale across the back to redirect snow melt and major waterproofing had to be done due to the enormous amount of water moving through and over the soil. I learned a lot about bentonite and Greatstuff foam. If you looked around carefully, you could see evidence of really old land usage. To get an area useful for most any purpose, rocks and boulders had to be moved and they wound up as piles or road edges or dams so you could use that as a starting point to discover old structures, graveyards, etc.

Those sewer and water pipes tell a lot. Many in our area were encased in clay to protect them from the nasty winter conditions. City trucks often carried bags of Bentonite to pack around the pipes after a repair.

One of the things about bentonite clay is that once it gets saturated it is pretty difficult to move it somewhere else. I found a masonry trowel dipped in water to be the best tool to use for the saturated clay even though it was slow work. While it did eventually obey the laws of gravity, it did so very, very slowly. It is very, very sticky. If the clay can't absorb any more water, you can pour water on it all day and only a small amount washes off from the main mass. It settles in the first dip in the ground and starts a new deposit. It really seems to resist mixing with other soils, especially silt, although it does pick up a lot of sand.

Those canals were the engineering marvel of their time. It was a shame that they had to be replaced by the railroads. Of course they were only a seasonal transport but in an area where there were huge bogs and roads were sometimes logs laid side to side, it was a huge improvement.

Yes, the canals were dynamic. The water had to come from somewhere and rainfall was not enough. Branches had to be dug to existing rivers and lakes to supply the needs of the canals. To get through the bogs, huge causeways were built and the canal was built far higher than the surrounding landsurface while water was pumped up and over into the canals. Eventually this drained much of the swamps and bogs and new meadows and rich farmland appeared. This had an effect on health, the economy of the region, the ecology and landuse. While the canals have mostly been filled in, it is still possible to see parts of the causeways. The source of the water in the bogs was often an artesian well. These were capped and the water contained. Often there would be farmland on one side of a causeway and a lake on the other with the causeway acting as a dam. Sandy

The whole preservation effort is a mixture of win and lose; it is important to pick your battles carefully. Archeology is in itself a destructive research method--once you dig it, the context is gone and the site now exists in what one hopes is a thorough report for future reference. Where sites are known to exist but are buried under another stratum of history - highway, parking lot - the site is preserved and remains a resource for the future. Future knowledge is very important to many who study the past.

This is likely very exciting to green_skinnydipper and very helpful.

Clay is one part of mineral soil, the finest particles with the finest pore spaces. I suppose there must be as many types of clay, by mineral content, as there are the types of rocks it derives from. From what we have been saying, it strikes me we are sort of comparing apples and oranges. Clay good for pottery may not be ideal for puddling. Clay good for puddling may not be good for bricks. It also seems that clay put to commercial uses is usually augmented in some way, something added for its intended use.

So green_skinnydipper, you have been on target while we have wandered all over the landscape. You found a good type of clay, know how you want to puddle--methods and lifts, and want to know how to seal the edges to prevent drying and cracking.

In my semi-informed opinion, the capillary barrier makes sense and should be viable. It helps draw up moisture, keeping the temporarily exposed edges damp, bleeds a little moisture out, and makes an almost textbook example of the hydrologic cycle. Something informative to talk about with fellow swimmers while skinny dipping.

There are many ways to skin the cat, they say. What you are undertaking is some form of traditional puddling. Sandy talks about roll-out sheets of material. How thick are these, how durable in terms of dryness, shrink-swell. Intended for an active (swimming) pond or something else. Doesn't strike me as ideal for this.

Tamping with sheep, horses, cows, serfs, children, gas-powered tampers--all been done. We hold up these historical examples like canals, but what did they use, what was their "ditch" like, how did they tamp, repair? Ultimately you will find what works for you where you are in terms of climate, evaporation, underlying soil etc.

My specialty was industrial archeology and it was mostly 19th century, maybe 100-150 years before I showed up. It was fascinating to discover that what was once common and taken for granted - making a water turbine work to run machinery that mass produced wooden items from window sashes to pill boxes, was no longer well-known and disappearing fast. A lot of the information on the technology was lost as we raced ahead into the future. We studied existing sites, found old-timers to share knowledge and finally found the lost manuals and texts. But it was mostly oral tradition. We filled in gaps and we tried to compare "as planned" with "as built" all in a cultural and historical context. So the "how" was always implicit.

Try to find a UNIVAC. Try to find anyone under a certain age who knows what it was. The Romans developed hydraulic cement that still holds stones together. Somewhere it was lost and only re-discovered when necessity for building the canals required.

Too many reminiscenses here. green_skinnydipper, you are right on target, but I have a couple of questions if you want to join in your own string!

One, why clay instead of simple liner (natural feel no doubt), two does your research show any value of puddling over a liner to avoid wicking into the native soil (or disadvantage over a liner), three what do you think will be the result of puddling over what seems to be some kind of loam to sandy loam? Do you have to prepare the underlying soil in any particular way?

The test for determining the percentages of sand, silt and clay is quite simple; I do it a few times a week. Send me a baggie and I'll do it to make up for taking so much of your post!!!

It sounds like a lot of work--did you ever say how large the pond/pool will be? What weather conditions are ideal for the undertaking? This is a great project, something I would have enjoyed being part of earlier on.

I hope you have time to respond to us, let us know these details. We will enjoy learning from you. Good luck, Sandy and I may not disappear yet!

Mike

Mike,

Thank you for the post. You ask some great questions, some that I repetitively ask myself as I plan this natural swimming pool.

Why clay? I don't know. This project started as planning a chemical swimming pool in a small area of our backyard that is not used or enjoyed for anything. I like to swim and spend a lot of time at the local pool. One of the problems with chemical pools is that the chlorine evaporates pretty fast out of the water right at breathing level. I know that after swimming in a chemical pool the inside of my nostrils are dry and my throat will often have some irritation from the chlorine. A few years ago I built a large house with an indoor swimming pool. When I bid out the pool construction I started asking different pool contractors about reducing the amount of chlorine because the home owner did not like the smell. I learned about passive ionization and other types of chemicals. When I started researching passive ionization and other alternatives to chlorine I stumbled on natural swimming pools that use plants for filtering. When I started researching natural swimming pools I stumbled on puddled clay liners. I like the idea of using clay because it gives me a completely organic pool and it appears I have the right type of soil for it.

There are several disadvantages to clay. One is the additional work. Tree roots will naturally seek the moisture from the liner and eventually penetrate the liner. The installation process must be very methodical to ensure the clay is thoroughly puddled and does not dry out during installation.

I think that by using the vibratory roller combined with thin 3" lifts is the best insurance for a fast and thorough puddle. To prepare the subsurface of the pond I will remove all the large rocks and tree roots, dampen the soil and compact it with the roller. I am debating on installing a poly liner or geotextile fabric between the subsurface and the clay to prevent tree root penetration. The clay will be puddled to about 12" thick with highway grade geotextile fabric over the clay for protection (salamanders and newts apparently like to borough into the clay).

If all fails, all I have to do is drain the pond and install an EPDM liner directly over the clay.

The pool is intended to be a lap swimming pool, so it will be long and narrow. The swim area will be five feet wide and about forty feet long and slope from four feet to six feet deep. There will be three feet of planting area around the entire perimeter. This will provide slightly more filtering than is required to maintain healthy water. There will be a dry stacked stone wall separating the swimming area from the filtering area. There will be one small pump circulating the water from the bottom drain, through a sediment chamber, to a skippy filter and down a small water fall to the plant filter area.

I just recently started drawing up my plans and will post them on here once I get them far enough along to make sense to more people than just me.

I would love for you to test my soil, will you send me your address?

Please keep the questions coming!

Maybe I should leave well enough alone but I reread some of this thread and thought I should add to a statement I made. I said that bentonite liners are shipped in rolls. I should have said sometimes, but not always. It is done by some companies who use a geotextile lined with the bentonite. They also ship in panels and bags. The material is laid out and the edges joined by the bagged bentonite or overlapped. Then it is wet down and puddled.

I ran into a few other things in my reading that could deserve attention. The first is movement of the ground. Since I have not lived in an area where ground movement is common I haven't taken it into consideration. Is there significant movement of the ground where you live, Green skinnydipper?

One site for a contractor who builds clay lined ponds suggests that if the pond is not connected to a creek or stream to keep water levels up, you should dig a well to do that. It seems to be overkill to me but I could see that for a very large pond.

Another thing we didn't discuss was the self healing properties of bentonite in a pond. A non catastrophic leak will self seal because bentonite suspended in the water will be carried to the leak and will deposit itself in the crack or hole. This seems to be due to an electrostatic charge in the bentonite itself. How great is this! I learn something new everyday.

One more thing. Sorry, I can't resist. The type of clay used for ponds or canals, etc. is sodium bentonite. The type used for medications and cosmetics, etc. is calcium bentonite. Sandy

I've ran across the bentonite sheet liners on The Google. It looks like a good product.

Keeping a constant water level is one of my concerns that I haven't quite found a good solution. I found ground water directly under my basement slab during a remodel. I'm secretly hoping to find a ground water source when I excavate the pond. I'm sure I wont be that lucky though. I'll probably end up with an auto filler from the domestic water supply.

I'm not sure about your ground movement concern, Sandy. Can you elaborate a little more?

I was reading a post from someone in Texas who mentioned ground movement was a concern in that area. I suspect it was in the Houston area or close to the coast where there is significant potential for high levels of groundwater which makes basements and tall buildings difficult if not impossible. Erosion, decay of buried materials in new housing areas, settling of the subsurface and destruction of swamp land, etc. are fairly common to those areas and such things as in ground cement pools are shortsighted.
I haven't lived in your part of the country except in an apartment so I don't have any knowledge about the ground in your area. I grew up in a very large house with a basement near the Ohio river. One night I was thrown out of bed by an abrupt and very scary movement of the whole house. I saw one window bow out briefly before the house settled again. I found out the house was built on soil deposited where the Ohio had once run. There was significant rain water moving through the soil at that time and the ground shifted. We didn't find much damage although there were some cracks in the masonry, the windows were not sliding as easily and the draperies were no longer true. The neighbors stopped using the small cement pond in their yard since it did have a large crack. Here, there is more than one housing development that has a lot of water moving through the soil in streams that shift around. One house I was in was shifted out of true in a major way. There were lots of cracks in all rooms, the toilet seals had to be replaced and the basement had water running down the walls when it rained.
That kind of movement where the whole structure moves at the same rate is OK. It is when only when part of the structure moves that there is a problem. This kind of damage could be repaired in an earthen pond but it could be plagued with leaks afterward.
Have you looked for a water witch? LOL! Sleepless

I shouldn't have any drastic movement like you describe. That sounds like quite a night!

My Great Grandfather and I witched for water once. We each had one hand on the branch and were holding hands. It was great fun. My Dad never dug the well to see if my Great Grandfather was right, he was a well-witching legend in his time. Brings back great memories.

Trying to sort out all the information...am I correct in reading that you intend to create this lap pool using puddled clay as a liner but then encapsulate the clay with a highway grade geotextile? Until I reread that I had a picture of you swimming in a clay channel with great turbulence from the activity.

Assuming this will be outdoor pool. Will it be in use year-round? Will you add chemicals or turn over water regularly? The clay and fabric will absorb and presumably hold chemicals fairly permanently--Sandy is our chemist here.

Geotextiles I have seen wick water and maybe yours will simply keep the clay moist all the time, even to the top of the lining? Is the material abrasive at all - what will it feel like when you scrape against it skinny-dipping?

The bentonite is interesting - what is the difference between Wyoming bentonite, Texas sodium bentonite, etc? Isn't it all doctored one way or another; milled, additives for different uses?

Great project. You have to be the only person I know who secretly hopes for shallow groundwater near their house! Careful what you ask for!!

Looking forward to hearing more.

Mike

The Wyoming Bentonite swells more when wet (up to 1000%) and I believe the Wyoming bentonite is all natural un-altered clay. The more I learn about Wyoming bentonite the more I think I am planning on using too much of it. I don't know much about the Texas stuff.

I have thought of building a temporary green house for winter and solar heating the water, but it will likely be in use spring thru fall.

The geotextile is not abrasive. It may wick enough water up to keep the edge damp and prevent drying but I don't want to count on it.

No chemicals. A small pump will turn the water over slowly so the plant zone has time to do it's work. I would like to add a sediment chamber to make maintenance easier, a skippy filter for added filtering, and a waterfall for aeration.

I doubt that I will find water. There is a fairly deep storm water "creek" running adjacent to my property. The creek was dry all summer because we have had little to no rain here in Northern Virginia. During average spring rains there is ground water coming out in two distinct spots that are eight to ten feet below the top of water elevation for my lap pool. I will not be digging that far down.

Oh, Mike! The extent of my ignorance concerning Chemistry is enormous. While I was not voted the most likely to set the Chem Lab on fire (the head cheerleader and the class clown had that honor) I doubt I would have been among the favorites in mixing and fixing. I am of the opinion that those who have a talent for that kind of thing have been put here to make up for my lack. I have no compunction in turning over the lab apron (with the burnt edged holes where the burning magnesium bits landed after they came in contact with water) to those who can figure out all those capital letters and numbers.
I did a Google search on Bentonite lined ponds and found some facinating factoids. Did you know that Bentonite clays are formed from deposits of ash from volcanos? I learn more and more about volcanos. I buy ungodly quantities of Perlite every spring for my gardening projects. I think I like volcanos (extinct, of course). Mike, did you ever get to dig around Vesuvius? Lots of interesting ash deposits there.
The difference between the Texas Sodium Bentonite and Wyoming Sodium Bentonite, hummm. You've got me. I do see that the Texas stuff is mostly white and some of the Wyoming stuff is red. What we used to waterproof our house was pale grey. I wish I could remember the name of the company it came from but over the course of 21 years I'm sure there have been changes in ownership. What we need here is a graduate of Texas A&M. or the Colorado School of Mines.
Mike one of the things I learned about clay is that you don't want to mix anything into the raw clay or even mix different types of clay together if you plan on adding heat. The result most of the time can be explosive. You can paint on a piece of pottery with slips (a watery suspension of clay)or with glazes or engobes but some very weird things can happen to clay in the heat of a kiln. Now glass is one of those substances that can have all sorts of impurities added that can change color, texture etc., but glass is primarily silicates (sand) to start with. Did you know glass is actually a liquid? It just looks like a solid because it is really, really slow.
Gsd, I get called on from time to time to give talks on greenhouses including the temporary type. I have a number of adaptable plans or locations for proven structures you might be able to use. Even though I had a 32 foot greenhouse it was never big enough so I was always building one or two extra each year to cover the excess production. I have also seen (even helped build) some great box kites. Sandy

Sandy and Joel,

Interesting factoids. I am aware that bentonite comes from weathered volcanic ash--ancient deposits.

My guess is that the difference from place to place in Bentonite has to do with the mineral or chemical composition (Sandy, I guess you won't do an analysis for us!).

I don't know a lot about clay except to say I grew up on great former inland sea clay beds on Lake Ontario and sort of have a thing for it.

I never dug at Pompeii or Vesuvius but have been at and studied them some. Mind boggling

Other than puddling clay, the only clay items I have studied in some detail is prehistoric pottery, the development of which enabled food storage and changed life tremendously. I worked with Native American pottery and have seen enough shards and fragments to note how variable the firing process was. A lot of the decoration is called dentile, where patterns were made with a sharp object sort of punching dots, and cord-wrapped to make designs and then fired. Gross simplification. I am learning here too.

I can understand wanting to play in the mud, actually do something practical and useful--lots of us are still little kids at heart jumping in the wet dirt.

If green_skinny dipper is still there, how long do you figure it will take to do the puddling? Once started can you stop or is it necessary to keep the project wet and rolling? What about relative cost of Bentonite vs a liner or having that spray-on application?

My guess is that it is because the challenge, the input of thought and energy, the appeal of the clay is just there and doable, something more gratifying than the old epdm we all toss is?

Really admirable, maybe zen or metaphysical, a philosopher's pool. Cool. C'mon back green-skinnydipper, hope you don't mind roaming around your post.

Mike

The challenge and appeal of spending a few days with my family and friends puddling a rather large pool by hand and foot does have a certain zen that initially atracted me, but alas, I will be puddling by machine. I will be using a walk-behind roller and should only take a few hours. Excavation will be done with a mini-excavator. As you can see, I am a conflicted person, all natural pool built with heavy equipment =).

These conversations are great! I really appreciate you taking the time to ask questions and continue the discussions. I have re-evaluated and revised my plan several times which is what this is all about. Sandy and Mike have provided some invaluable information and asked the right questions to keep my research heading in the right direction. I am confident that when the time comes to break ground I will not need to worry about a leaky pond (although I will).

Ponds have become common here in suburban Washington DC. New shopping centers and business centers are growing like weeds in Northern Virginia and Fairfax County has been working on using natural ponds as a means of rainwater filtration before the water is released back into our environment. I find it very intriguing. I am in construction and we just lost a bid for a Fairfax County owned facility that had rainwater filtration gardens. The plans were beautiful but the ponds were concrete so no help for my project.

Mike, I didn't get my sample dug this last weekend. The Holidays and all. My curiosity is killing me though so I am excited to get out there and dig a test hole.

Not intentionally hijacking my own thread, but I am looking at using solar power for my pumping system. Anyone have any experience with solar pumps? It looks like I will need several since they are low volume. I will also need batteries to store power for night and cloudy days. That is about as far as I've gotten.

Oh the joys of being sleepless! I got the idea of doing some searches for details of the construction methods and then thought that even if the Purdue Extension doesn't have a publication on the construction of ponds yet, maybe Alabama did. They usually have a good selection and sure enough I did find a worthwhile publication.

http://www.aces.edu/pubs/docs/A/ANR-1114/

Virginia didn't seem to have as good a selection although the last sentence I found said there were more through contact with the Extension Service. Then I got sidetracked by a suggestion that you could control the crayfish population by eating them rather than just killing them. I am putting in the link for a site that has some pertinent info on construction details and some other good links. You might want to scan it for anything you may have missed that should be in your construction plans. Sandy

I understand what you are up to. I had to do everything by hand and I don't know which was worse, digging the pond or moving out the backdirt. I consider my feature to be a sort of landform composed of rock, water, motion, noise and vegetation. Maybe a little Zen, but a mini-excavator would have been heavenly and not left me conflicted!!

Won't the sides of your pool be clay lined as well? How will you compact those?

All those detention/retention/infiltration ponds are a blight on the landscape to me. The major problem is that there often no clear line of responsibility for cleaning, controlling invasive vegetation (which will appear) etc. Too often they become an expensive insect breeding ground and sediment keeps them from functioning properly.

My experience in a couple of states in the NE is that the ponds are designed to allow water to infiltrate downward, recharging the ground water as well as overflowing into rip-rap and ditches. Construction design to speed up or slow down infiltration is where clay lining may come in. But since they should "leak" they aren't quite what you are constructing. Virginia may be different of course.

I have no doubt you will be sending a soil sample eventually. You are really focused and I like it.

I have a post on should this pond freeze that exhibits my focus (stubborn determination to do what I want anyway?). Take a peek at my pics--more in the gallery.

For the occasional posts and questions about natural ponds, you are rare in really sharing lots of good info. Enjoyable.

Mike

Wow Mike, I just read your post about your pond freezing. I hope it all works out. You dug all that by hand? You free one weekend this spring? Do you charge more than a mini excavator rental? =)

Your pond is beautiful! Very inspiring.

Back to my story, saga, planning, or whatever it is that I'm doing...

The sides will be clay also but will be gently sloping so the roller will easily run up and down the slopes for compacting.

The ponds I've seen constructed lately are much different than you describe. Maybe they are not infiltration ponds, but just landscaping ponds. I'll try to snap a photo of a new one I drive by every Monday.

I'm glad you are enjoying my pond planning rambling. Just for kicks, I re-read this thread the other night. I've decided I must be a little off the deep end. (= But then I see ponds like yours and realize all the agony of planning and changing my mind every ten minutes will pay off this spring when I finally give up and just dig the darn hole.

You got it - when you put the first shovel or excavator bucket in the ground, most of the planning and indecision etc will on reflection be the hard part in a sense. I found there were some rough patches during construction when I knew just what I wanted to accomplish and had no clue. If I could do some things over....we all know that story.

My experience has been that as I learned I sort of gained confidence altho you need to be a jack of all trades it seems--with your background should be OK. But then something like the freeze happens, I was clueless and a bit in a panic. Got good help and am now ready to attack winter. Something else will come up I will resolve or holler for help again. Your experience will be smoother I expect.

You aren't off the deep end at all. You want to accomplish something different to suit yourself and it takes thought. Sounds simple--dig a hole, play in some great mud, move some water around. Maybe a little greenhouse, maybe this and that--a ponder.

Well, I do work pretty cheap now but I wonder about a whole weekend. What do you have planned for me to do the second day? Actually, the key to good pond construction is to make friends with very large, strong people.

I like it, will ramble along here as much as you like. No experise doesn't mean no opinion! And all is in order with my frozen pond (right now)

Mike

Mike,

Glad to hear your pond is okay.

Don't have time this morning to talk about mud and clay. Darn job sure can get in the way of a good time. =)

I have some sketches I'll try to scan and post tomorrow.

Have a great day!

looking forward to sketches, more clay info. maybe you will get pic of "ponds" you mention?

Out of the winter woods for the time being.

Mike

Hi,

Years ago, I built at 37' x 25' x [0.0 to 5'] garden pond using 45mil epdm liner. I only recently saw a catalogue of excellent bentonite clay-built ponds and now regret having used liner - or so I think, pending responses on this forum.

The down-sides to using synthetic liner (vs clay):
*Difficulty of repair should a tear occur - including from tree branches falling in.
*A terminal life-span; may not last a full life-time, in case that matters to you
*There is a potential that moles/voles and other ground-rodents may bore into the liner. Underlay - such as carpeting, I suppose, would have to be adequate. Tree roots may also piece the liner; not sure if this is also so of clay-based ponds.
*You cannot plant things like cattail (Typha spp.), or other plant species which would puncture the liner; I'm not sure if this is still the case when it comes to clay-built ponds, however.
*Any exposed area will reveal rubber, instead of a natural looking substrate: clay; you'll need more stone coverage to conceal the entire surface of the rubber - which may be an issue for those not wanting stone in their pond, due to maintenance issues. You'll also need the stone to conceal all of the unnatural creases.
*For complicated designed, you will need to purchase far more liner then necessary.
*For very large liners, there is difficulty in installation - I'd rather deal with the clay-pond challenges.

So, I'm thinking of dumping my pond, cutting away all of the liner (leaving the bottom drain in place), and removing all of the underlay (carpet) and going with sodium bentonite.

These are my concerns:
1. Will tree and shrub roots (particularly wetland species - i.e. willow, blackgum, and birch, etc.) penetrate the bentonite, being in search of water? There's no way I'm doing away with the awesome wetland plants I planted in my mesic soil around my pond - natives: sweetbay magnolia; paper birch; blackgum; common button bush; various shrub dogwood spp.; coastal sweet-pepper bush; silky willow; highbush blueberries; American black elderberry; and thicket-serviceberry. If so, I'd rather stick with liner.

2. After rain-storms, my water-table rises. For instance, if you dug a 5' deep pit in the yard during a dry month, there is no water; after it rains, there is water to the top. Excavating the pond confirmed this. Wouldn't the groundwater pressure (which would cause the rubber liner to lift if I were to drain the pond lower than half-way, as it is) cause the clay-seal to rupture?

3. I actually have a yellowish clay once you dig about 2' down. It is not impenetrable, but I guess it would be a little bit of extra protection, beyond the standard depth of applied bentonite clay. Do I have the proper conditions enabling me to build a clay pond?

4. Can I plant emergent aquatics with deep, penetrating roots in a clay pond? Plants like: cattail and common buttonbush?

Thank you,
Steve