Did I just create a water tank when I dug the hole for my organic pool?

I dug this hole in the dry season as the beginning of an organic pool - 50% plants, 50% swim area.

We decided to wait for one rainy season to see how it would react to water prior to fitting the liner.  

If water were to push up under the fitted liner it would be a serious headache to fix.

After 3 days straight of heavy rain it appears that the hole may have self-sealed?

Another explanation is that this is the actual swollen water table, but that seems unlikely.

Other smaller holes on the property are also filling and retaining water.

Does anybody have experience with these tropical red soils and water tanks?

Have I inadvertently created a natural water tank which may require no liner?

Thanks in advance.

One way to check if it is just the ground water level is to mark the water level and then empty six inches out by pump or bucket. Then mark the lower water level


Leave overnight or 24 hours with no new rain: if the water level rises past the lowest level, it's the ground water level.

If it stays at the lower level, you still aren't out of the woods yet...research your soil perculation rate.

The  first higher mark will indicate rates for you if you get movement in heights and also tell you if the ground level water is somewhere between the two marks.

I am mighty jealous.

My pond, which I put bentonite on but obvs not enough, leaks the water our slowly over several days. If it continues raining it can take a week for the water to fully leak out. So if it stops raining and that water level doesn't go down much I'd say you are golden and....

I am mighty jealous!

If you do manage to hold water, be sure to stock it with something that will gobble up mosquito larvae. Until then , you could use moringa seed cake to clarify the water and the saponins should kill any mosquitoes. It might be wise to find out about the various reptiles that might take up residence. You don't want to pop in for a swim and find that you are sharing the pool with a coral snake or saltwater croc. Mobile version doesn't tell me exactly where you are.

I'm guessing that your clay soil has a low seepage rate , but without intervention the water will slowly leak out.

Nice project! For mosquitos I use BTI (bacillus therengensis israeliai (sp?)). Kills the larvae and is non toxic, making your pond a trap for any egg laying mosquitos in the area and the end of their line. It also does the same to many biting flies in the mosquito family.

Thanks Ben for your great advice on the prevention of Mosquitoes, I found this product which has good reviews; Summit Mosquito Dunks.

Dale I have never heard of clarifying water with Moringa seed cake, I will research that further, thanks for your suggestion.

Elle, I have been considering my options with regards to sealing this project.  

I am inspired by the work of David Butler in the UK.  He left his media job to design and build organic pools - that is a pool with 50% plants and 50% swim area, no unnatural filtration and just a small air pump strategically used for circulation.  There is not need for fish in this system, just plants.

Here are a few photos.  A finished project by David Butler.



David's sketch for a pool suitable for a tropical climate



What you can see in my initial photo is the first stage of the construction, the dig.  I decided to wait a season to see what happened to the naturally occurring water on my site.  The water that has accumulated is either slowly draining away from the clay soil to meet the lower water table or this is the water table.  Before I can proceed with my project I must be sure that this is not the water table.  If it is and I decided to use a liner I would need to fit an extensive french drain system under the liner to avoid it being pushed by with the water pressure.

David uses liners on how projects, and if I were to do the same then the next step would be to build two retaining walls.  One on the inner deeper hole and one for the bigger outer hole.  This would then be covered with an insulating layer of something soft, then have the liner applied.  

I have been toying with sealing this hole with cement (like the water tanks they build in India) or even using bentonite clay to avoid a liner altogether - liners are expensive and can be difficult to fit.

Well thanks for listening, thank for your comments and suggestions.  I'll take all the help I can get.

Zach weiss built some natural swimming pools and used a liner in both that i have seen ( youtube - elemental ecosystems)

It is interesting because he will not do water retention landscapes (ponds) unless there is enough natural materials on hand (clay, etc). The fact that he uses a liner tells me a liner is needed. The question is why.

Maybe so you can swim/bathe without muddying the water?  Any ideas?

I wonder how you avoid leaches in a natural swimming pool/swimming pond? Especially without fish.


The pond on my parents property was created when some long ago owner started digging out a small peat bog to sell the peat. He hit a spring, and the pond has been there ever since. So, the PH is very acidic. Water plants and fish fare poorly... it is loaded with big frogs, and terrifying leaches.

I have a vivid childhood memory of my dad needing to swim down to retrieve the submerisble irrigation pump after it detached from the float... you could see numerous leaches silhouetted above him as he swam down into the murk. Eeeech.

Regarding leeches.. a quick search and i found this: https://pondinformer.com/pond-leech-treatment-guide/

Considering that a swimming pond is lined, it could be vacuumed every few months i do believe the problem
sludge buildup can be avoided.   It does remind me to put a fine filter on any water coming from my river pipe. My plan is to ultimately use the well pump (once I have it installed) so that all potential contamination of leech and fish eggs can be avoided.

Thanks for your input ;-)

Something is going to live in that water. Nothing beyond heavy chemical treatment could prevent that.

One effective method of eliminating mosquitoes is to completely cover the pond with azolla. this will also give you a high protein fodder crop. Azolla takes nitrogen from the air so the limiting factor is almost always phosphorus. It turns a crimson color when phosphorus is in short supply.

A net system could be used to pull the azolla to one side during swim time. Collect the days harvest and release when you are done swimming. Sort of like putting the pool cover back on. It will quickly gobble up nutrients from runoff or bird shit.

One thing you may need to check on , is whether any type of bad bacteria likes to grow along with it. I've read some dire warning about swimming in tropical freshwater , due to various microscopic life. Went swimming in a beautiful waterfall last week and i'm still standing .

My guess about tropical freshwater would be that pathogens won't like the highly aerated water downstream from a waterfall, but I could be mistaken. That also doesn't say anything about other small living things that might like to take up residence inside you. I know there's a species of catfish in the amazon that has been known to attach itself inside human urinary tracts, and I imagine there are many scary possibilities.

I love the azolla cover idea. It would also shade the water, maintaining a higher oxygen carrying-capacity than if it were warmer, and suck up nutrients that would otherwise promote the growth of algae.

Good work, Simon, in any case. We appreciate the pictures. Keep us posted and good luck!

-CK

Many other people were swimming in the waterfall. Someone decided to get rid of their gum and it ended up in my swim shorts . I wore those shorts for another 6 hours until we got home . Then I discovered that I was glued to my shorts. So I got a free Brazilian wax , not to the main junk , just to the side of my ass. At first I thought it was tree gum or something, but it had a strong smell of spearmint.

I've looked into a natural pool and came to the conclusion that aerating the water somehow might be a good idea. Farmers here do it for some of the fish crops so it seems like it might be worth investigating.

Chris Kott wrote: I know there's a species of catfish in the amazon that has been known to attach itself inside human urinary tracts, and I imagine there are many scary possibilities.

You are referring to the candiru. There is controversy as to whether it actually does that; Wikipedia is clearly skeptical: Wikipedia: Candiru. In any case, supposing that it is true, it would appear that you would protect yourself by wearing something there while swimming, and/or, avoiding urinating in the water.

A bigger concern for me would be leptospirosis. It occurs where infected animal or human feces or urine have contaminated the soil or water. On the other hand, I swim in the Rio Magante frequently, knowing that there are farms and cattle ranches upriver, and I have not had any problems with it. But then, I don't ingest the water except through my LifeStraw filter!