Pool to pond?

I have a rectangular 20'x40' inground pool that I no longer want or use. I put it in about forty years ago and now that I'm facing down 65 years old, I find that I don't really use it much and I'm just tossing money at it in chemicals, time and effort.  Last week, as I was fighting with the cover, I was thinking how I really need to do something.
I would like to maybe have it be a pond and was wondering if anyone has converted a pool into a pond and what would be required.  I know that it would need some sort of aeration, and I'd like to have plants and fish if possible.  It does have a deep end, so at least eight feet deep there while the shallow end is four feet.  
I do live in zone 5 central Vermont, where we do have cold winters...although it's not been as cold as it used to be.  We had been a zone 4.  Where we used to get light, fluffy snow, it's now more wet, slushy stuff. Sometimes, the temps will dip to 20 below, but that is rare and when it does happen, it usually only lasts for a few days.  
I mention all of that because of wanting fish.  I'm hoping for that symbiotic relationship between the plants and animals.  Anyway...is it possible to do this?  Has anyone out there converted a pool into a pond?  Is it too deep?  If so, could you let me know what was involved and whether or not you are happy with the results, or should I just hire an excavator to remove the whole thing?

It should be totally doable.  When you have the right balance of plants and animals in the pond, you shouldn't need a filter or aeration at all.  Hardy fish and other creatures won't have issues surviving winter since if the pool is full, it shouldn't freeze all the way to the bottom, assuming it's at least a few feet deep.  One challenge might be adding a shallow water plant zone, which will help with water quality and providing habitat.  A floating island may be a viable solution, unless the pool has a shallow end for children, in which case large pots and other containers can simply be placed in it.

Good point Alder, the shallow zone is important. How about a floating raft with plants filtering the pond?
I've seen those in Amsterdam, tthey do a great job of cleaning the water.
I'd wait with fish or look for fish that do need eat all plants, like those orange koi that destroy kill ponds all over the world.
I have a tiny pond with a great balance between fish and plants, but the fish are not over there in USA.

The pool does have a shallow end which is 3.5' deep or so.  I love living in Vermont, but one of the downsides is that there isn't a huge diversity of businesses, and I wouldn't know how to proceed without help from someone who has done such projects before. (For example, when I discovered Permaculture a few years back, I also discovered that no local nurseries sold fruit trees other than the standard apples, pears, cherries and peaches.  I ended up having to order most everything online.)
Obviously, the pool has electricity to it, but it would be a dream not to have to have anything "plugged in" and have the symbiosis between plants and fish take care of it all.  Frogs do jump in all of the time, and because of my plantings, I do have lots of birds and dragonflies, etc.  A friend suggested tilapia--not something I'd be too keen on, but certainly a possibility as would the koi.
When I went to town and was waiting to donate blood, I went outside because it was a glorious day; there was no place to sit so I walked over to the culverts by the street and was shocked to see about ten crawfish in the water.  A bird must have dropped it from somewhere because it's more or less just an overflow for road runoff.  It would be cool to even be able to raise them!  I've never tasted one myself and have always assumed that they were a southern delicacy....of course, that would mean that I wouldn't want to dip a toe in on a hot day!

That is a great idea for repurposing a pool into a pond.

As I get older I am wishing a had a pool to do exercises in because that would put less stress on my body parts that get to aching as I get older.

Even if you turn the pool into a pond it would still be available for swimming.

Here on the forum we have had some other folks who wanted to turn an unused pool into a pond.  Some because there is less maintenance.

Here are some threads that you or others might find interesting:

https://permies.com/t/65790/Swimming-Pool-Pond

https://permies.com/t/224104/Converting-traditional-pool-natural-pool

I hope you will let us know how this turns out.  Maybe even do a Project thread.

We have an in-ground swimming pool that became a pond. It wasn't something we actually planned, but once my husband removed the fill dirt and it rained, we eventually ended up with frogs, dragonflies, and all sorts of pond critters. You can see photos here - https://permies.com/t/153620/Unexpected-Frog-Pond

Ours has a crack in it so it won't stay full. It's a sunken pond. I've added pond plants and it's really a pleasant addition to our homestead.

Did you make any progress with this Barbara? A living pond gives many more functions than a swimming pool.

I did this, more or less successfully, and posted in one of the other threads.

Douglas Campbell wrote:I did this, more or less successfully, and posted in one of the other threads.

Good description here: https://permies.com/t/142402/knowledge-installing-ft-ft-pond#1124874

More here: https://permies.com/t/275173/ideas-Convert-pool-aquaculture-build#2877703

Douglas Campbell wrote:I got some large feed bags, put them on the bottom in corners to create structure, and filled them with pea gravel.
I used some patio stones to build steps and some other structure.
I got a bunch of people to help drape the EPDM down into the hole, and out over the edges, in one big sheet, over the bottom, the 'structures' and the excavated perimeter.
I refilled with rain water and tap water.
I put pea gravel on top of the EPDM over the excavated perimeter.

I used the old pool pump, on a timer & photocell, powered by solar panels, to circulate water from the pool, through the artificial wetland (there were several iterations, including using some IBC bulk carriers to act as reservoirs for a water fall into the pond, that continued flowing after dark, for awhile.

That sounds great Douglas - I don't suppose you have any pictures still?

Hi
I failed to document the process, but here are two images of the outcome.
The artificial marsh is along the back.
In one image an artificial island is visible at left.
It was fascinating to watch nutrient fluctuations with the duckweed fighting for N & P with the artificial marsh; depending upon the year one or the other one would yellow through deficiency.
I used a pool dip net to harvest the duckweed for compost, or a scythe to harvest the marsh for mulch.
Mistakes:
i) I did not rinse the pea gravel I used as filler in the artificial marsh, so the system got a big dose of stone dust as fertilizer, making it eutrophic initially (would have been OK if the goal was to maximize biomass)
ii) I used a single sheet of EPDM roofing/pond liner, which is great stuff.  I should have used a separate sheet for the marsh, and 'shingled' it down over the edge for resilience.
iii) I did not layout the water circulation through the marsh optimally; I probably should have made the marsh more shallow to keep the full depth active, and used a pump/drain cycle to maintain oxygen.

It is critical not to create a gas/water tight pocket between layers of liner.  I left the old pool liner in place as a cushion but made many cuts and holes for drainage.  There are videos of ghastly pond prolapses when gas built up between liner layers...

It was a fun project, and less work than maintaining the equivalent pool, or even equivalent lawn, once setup.
The frogs & toads thanked me.
I got quite a few side eyes in our suburban neighbourhood for 'converting that lovely pool to a swamp...'
Then we moved away.

Thank you so much! That does look lovely.
I don't quite understand this:

Douglas Campbell wrote:ii) I used a single sheet of EPDM roofing/pond liner, which is great stuff.  I should have used a separate sheet for the marsh, and 'shingled' it down over the edge for resilience.

Wouldn't it leak if you had a join there?

Hi Nancy et al.
It would have been more robust & flexible to:
-drape the large sheet of EPDM from the marsh, over the lip, down into the pool (as done)
-then use a separate sheet of EPDM under the marsh, up over the lip and down the edge.
The edges and the marsh are the biggest risks of puncture, so ability to replace a sheet under the marsh would help.
Not a big deal.

I am still using left over scraps of EPDM for other projects; marvellous stuff.
cheers Doug

I made some phone calls and no one in the state seems to do this sort of thing.  I love Vermont, but it is lacking when it comes to many things. This is just one such example.  We're not "cutting edge" with things involving medical advances either, just as a quick example!  

Nancy Reading wrote:Did you make any progress with this Barbara? A living pond gives many more functions than a swimming pool.

Barbara Simoes wrote:no one in the state seems to do this sort of thing.

Sounds like an opportunity for someone then.
I'd be tempted to have a go myself - hire someone with a digger and make a workparty. What's the worst that can happen?

Quite a bit!  My friends and I call this "Barbieland" because bad things can happen in Barbieland!  If it wasn't for bad luck, I'd have no luck at all kind of thing!  

Nancy Reading wrote:

Barbara Simoes wrote:no one in the state seems to do this sort of thing.

Sounds like an opportunity for someone then.
I'd be tempted to have a go myself - hire someone with a digger and make a workparty. What's the worst that can happen?