Sealing and erosion protect a new small pond

Hi all - I have dug a small pond. I want to ask for advice for the best way to seal the pond for holding water and what I can do to protect and stabilise the sides for erosion.

I want to avoid cement and plastic lining the pond.
The soil is about 50-60% clay.
I am in North Thailand with a rainy season (4-5 months) and a dry season (7-8 months).
The pond is about 8x4 meters (13x26 feet) and 1.7 meters deep (5.5 feet).
I have planted vetiver grass around the edge.

Right after I finished digging, I tried to gley the bottom with cow manure, fresh grass cuttings and dry rice straw. It doesn't hold water (yet?).
My plan is to eventually have ducks in the pond so they will also help with the gleying process with time.

Any ideas/advice on how to seal the pond bottom and the sides?

I was thinking to line the pond with big rocks to stabilise it and prevent erosion. Would that work?

Any better ideas on how to prevent erosion?

Thanks!

If you can find bentonite clay that will work to seal the pond, it comes in the form of cat litter here or can be purchased by the truck load in some locations.as far as erosion plant some native fast growing plants and cover them with straw, and some netting to hold the straw down.

If you have a way to fence animals in the area for some amount of time, they will seal it for you.  Pigs in particular are supposed to work well because you can put a small amount of water in the bottom and they like to wallow around in the mud.  They will compact and seal a small area, which will then hold water.  As the water level rises, they play at the edge of the water, compacting further up.  This continues until the pond is sealed.

@Client and @Trace : Thanks for the ideas.

I will try to source some bentonite clay. Any references for how to apply it? (I am thinking in particular the sides).

I have planted vetiver on the edge and mulched with grass cuttings - should I plant on the side slopes as well?

I could fence the area around the pond - but I am not ready to take on having pigs just yet. Would it work with pigs even with the slopes that I have? Did you try it, @Trace?

My plan is to have the ducks in the pond next rainy season (since it is not holding water yet) and hopefully they will help gley it.

Thanks, Mark

How does this pond fill? It is hard to tell from the photos, but it looks like it has a bank all around it?

Vetiver for erosion control is a great idea, but I'm not sure how appropriate it is in your situation. For a start vetiver is intentionally planted to help water infiltration deep into the soil. The roots go down deep and open up channels for water to drain. This will potentially result in leaks around the edge of your pond, limiting storage.

Michael Cox wrote:How does this pond fill? It is hard to tell from the photos, but it looks like it has a bank all around it?

I have possibility to direct water from a larger pond on the top of the property through a channel behind me in the position where I took the photo. My plan is to put in a PVC pipe from the channel to the pond.
During the rainy season the whole area where the pond is get very wet.

Michael Cox wrote:
Vetiver for erosion control is a great idea, but I'm not sure how appropriate it is in your situation. For a start vetiver is intentionally planted to help water infiltration deep into the soil. The roots go down deep and open up channels for water to drain. This will potentially result in leaks around the edge of your pond, limiting storage.

Hmm. I planted it because I wanted it to hold the soil together and catch soil sentiment.

Yes, I was perhaps a little to fast on the trigger with digging this pond. Didn't really think it all through in terms of it holding water and staying stable. Well, I have 6 months until the next rain to figure it out 😐

Thanks for the input!

Mark Hansen wrote:@Client and @Trace : Thanks for the ideas.

I will try to source some bentonite clay. Any references for how to apply it? (I am thinking in particular the sides).

I have planted vetiver on the edge and mulched with grass cuttings - should I plant on the side slopes as well?

I could fence the area around the pond - but I am not ready to take on having pigs just yet. Would it work with pigs even with the slopes that I have? Did you try it, @Trace?

My plan is to have the ducks in the pond next rainy season (since it is not holding water yet) and hopefully they will help gley it.

Thanks, Mark

Mark, I haven't done it myself yet, I've only seen other people do it. There is a very good thread here on permies where someone documented the process.

My own house is being built right now on land I don't live on yet. As soon as we get settled on it,  I'll be working on a pond myself.  I don't plan to raise pigs, but I have a friend that does.  He is happy to let me feed a couple for one summer while they build my pond. They will go back to him in the fall.