I've not read Sepp's ideas on pigs sealing ponds and Sepp's use of an excavator bucket to reproduce the results. I've only listened to Paul talk about it and Sepp's brief video blurb.
I have never heard anyone say why it works. My theory is that the soil is stirred up which causes the clay particles to go into suspension and settle at the end. This puts a layer of clay on the top of the soil, sealing the pond. The same thing that happens in a shake test when checking if you have clay for cob.
There is a natural phenomenon by which a mixture of particles, when agitated, will naturally settle out according to size, with the largest at the top and the smallest at the bottom. You can demonstrate this yourself, or at the very least you can do this experiment in your head.
If you get a large container of some sort and add a bucketful of BBs, a bucketful of marbles, and a bucketfull of baseballs in no particular order, and then shake it back and forth, the baseballs will eventually rise to the top, the marbles will settle in the middle, and the BBs will form a discrete layer at the bottom. Soil does the same thing, except instead of you shaking it back and forth the pigs are churning everything up. When the smallest particles, which are clay, form their layer at the bottom, it's tight enough to keep water in.
Most things I've read refer to about this process refer to "gley" as a part of how it works. Gley was discussed in this thread: <http://www.permies.com/permaculture-forums/3409_0/permaculture/gley-technique-for-sealing-ponds-and-dams-and-walls> and elsewhere. There are also some pages on the net with pictures etc.
posted 7 years ago
I read about gley in that thread before, and it sounds rather complicated, with the potential for lots of things to go wrong. If you don't cover each layer properly then it seems like there could be some issues with raw manure or raw compost floating around in the water. What makes me further suspicious of this method is the need to add lots of material. Sepp does it without adding a thing (except pigs).
Also, not to be argumentative, but Mr. Argeropoulos and I are actually saying opposite things. I'm saying the clay settles on the bottom layer, while he's theorizing that it settles at the top. The laws governing the settling of particles are very well known and easily demonstrated. If you think about it, you will realize that larger particles have more spaces between them, so eventually smaller particles will slip through and descend until they can't go any further. I am trying to find a video I've seen before that demonstrates this principle but I can't seem to find it right now. I'll post it when I do.
You can also observe the same phenomenon in a box of certain kinds of cereal, or in potato chips come to think of it--the biggest ones are always at the top, while the crumbs are at the bottom. The same thing happens to soil particles when they are shaken long enough.
Ah, but when items are suspended in water, it happens differently. This is in fact the basis for an easy soil test, one we did in my college soil ecology class. You take a handful of your soil, put it in a jar with water, and shake it up. The first things to settle will be pebbles, followed by sand, followed by silt, followed by clay, which takes a very long time to settle out, followed by organic material which takes a super long time to settle out. Here's a website; description is at bottom.
O'course, I haven't actually read about the pond thing yet, but depending on whether water is present when the settling/agitation is occurring- I'm going to go look at vid now.
I'm a young and I'm not going to contort myself to fit in with our very ill society. I am a citizen of the world, not a mindless consumer. If you want to follow along with my journal, here's my blog: Life Happened Today
Anyone else have any personal experiences we could link to this page?
"Instead of Pay It Forward I prefer Plant It Forward" ~Howard Story / "God has cared for these trees, saved them from drought, disease, avalanches, and a thousand tempests and floods. But he cannot save them from fools." ~John Muir
I ran three red wattle pigs in a part time pond that always had water in it till august when the weather turned hot and dry. The pond held more water then it ever had. Once the pigs were sold and removed from the area, the water level went right back to where it was before the pigs. The pond only held water while the pigs were present. Perhaps ducks may have worked better...