THE NATURAL POOL MEETS ITS END

The natural pool is dead, expired, failed, collapsed, foundered.  

Having praised the idea – still probably a viable one, under the right conditions – I figured I should report on the end of this experiment.  I didn't know it would be an experiment.

Its best year was probably its first year.

Summer, year one.

A Worthy Idea

This is what I said about the idea of having a natural pool in my blog post of May 2017:  "Pools, for just about everyone, generally have hard-formed shapes made with concrete, tiles, plastic, with clear blue water and, of course, chemicals to keep the water clear and blue.  It's what most people swim in if they're not near the ocean or lake.  (Or even if they are.)  Not everyone likes swimming in rivers or ponds.  But I do." *  

I still like the idea of swimming in rivers and ponds, but it's become a bit harder to do that. My favorite, and nearest, swimming hole was the New Haven River, about a fifteen minute drive away at New Haven Mills. There was a photograph of it in that May post. A nice spot that you approached across a bridge to a dirt road where there was a small parking area. It was never crowded, and almost every time I was there there were no other people. But one day the parking area was blocked off; it had always belonged to the people who lived in the house across the road, and apparently the owners had decided to reclaim it.  I could only guess why; maybe there was trash left behind, or dog poop (it had been a good place to take your dog), or maybe someone partied there once too often. It's not that there aren't other beautiful places, but they can be crowded, and, well, you need to drive to get there. They're not right there. 

i wanted a swimming hole right there.

The schematic for a natural pool is simple, or at least it looks simple: plants filter the water, so chemical filtration isn't needed.  The frame is made of wood, wood that is kept permanently under water.  A plastic liner is underneath, covered by gravel and stones. Plants line the sides. 

What could go wrong?

Algae Battles

It was only a year before the first sign of trouble.

At the beginning of that season I noticed a few small clumps of floating algae. Being an algae naif, I was surprised. I turned to a water expert recommended by the people who built the pool and got expert advice.  I ordered a couple of gallons of "good bacteria" and understood that I needed to have some at hand, always.  Almost overnight the good bacteria ate the algae.  I hadn't even bothered to find out what kind of algae it was.  All I knew is that it was benign, not uncommon. and easy to get rid of.  

Little did I know that this was to be only my first battle with algae.  

The next year I found string algae.  String, or filamentous, algae consists literally of long hair-like strands.  Much of it can be pulled out of the water, sometimes easier said than done.  The larger the body of water, the more work.  (My pool is 12' by 20'.)  It's hard to eliminate it completely without using some sort of algaecide. The upside is that the water around remains clear, so if you can get rid of it all, the result is clear water.  Since the pond bottom consists of gravel and many rocks as in an actual pond, by eye you won't know whether you've gotten all the algae or not. 

More algaecide needed.  Eco-friendly algaecides.  Good bacteria wasn't enough. Pretty quickly I learned that there are many kinds of algaecides and that all algaecides are expensive. 

String algae in situ

To deal with algae I had to turn to the internet. There I found many stories of battles with algae.  Most of the algae stories are about issues with chlorinated swimming pools.  When you look up natural algaecides you find the issue is algae in small koi ponds so the advice generally doesn't scale up well.  Using the total amount of water in the pool, give or take 11,000 in this case, gives you the starting point for how much you need, but still, it's hard to know just how much of the stuff, how many applications, will solve the problem and not hurt the wildlife, the frogs, newts, and insects that have colonized the pond.  

Recommendations for getting rid of algae in eco-friendly ways included using barley straw.  But here's the thing: barley straw doesn't exactly kill algae; by releasing a chemical it inhibits further growth.  (The mechanism "isn't completely understood.")  I tried it anyway, floating some in the pond for a while. It was hard to tell whether there was any effect on the algae.  Was it growing?  Was it stable? There was another effect, however, a rotten smell that came from the wet barley straw.  Yuck.  I fished it out.  Other suggestions including baking soda and vinegar.  (Hah!)  Good for koi ponds, maybe. I began to suspect that eco-friendly may also mean mild.  It was time for heftier algaecides.

There are plenty of organic products out there for pond clearing. Each has a proscribed algae enemy.  That means you have to know what you're dealing with. String algae is easy to identify, but other types – and there are plenty without going beyond the benign group – are a bit more challenging. 

String algae up close

Did I say challenging?  Turned out there were various other kinds of algae, and, unwillingly, I was learning more and more about them.  

Another kind of algae visits!

Various kinds of algae found their way to the pond. There are at least two 
varieties here, maybe more.

As time went by, algae problems multiplied.  One kind would be done away with and another appear.  I had to be on the lookout through the summer.  Depending on the weather – hot and sunny guaranteed algae blooms – I had to be hyper aware.

Moss-like algae on the bottom, slimy algae in the plant area, at top, a combination
hard to beat.

Plant Battles

Are there too many plants?  Or not enough?  Is the ratio right?

Plants were happy from the start, and grew and spread.

The frogs were happy, too.  And there was no shortage of them.

The plants were so content they grew and multiplied.  And multiplied.  Some of the reeds were so vigorous they tried growing through the wood frame.  One year they were so enthusiastic they drooped over the water and needed to be trimmed.  Another chore!   The meadow seemed to encroach and overpower the plantings around the pool.  Weeding was about to get added to the list of chores.

Reset!

Enough was enough.  Time to make a clean start: more and better filtration, clean the walls and the rocks and gravel.  Refresh. Refill.

 

You'd think this would do the trick.

Refilled, and okay, but I'm still checking...

The fresh start never seemed fresh enough.  There were continuing issues with water clarity. I checked the water quality constantly, needing it to be stable. But there were constant ups and downs. Managing algae had not gotten any easier and there were so many different kinds.  One after the other, each seeking its place in the sun.  Hard water made it especially challenging to keep a constant pH. I could not let a day go by without a pH check and algae check.

By the summer of 2022 the pool was making me crazy.

Yikes, the water is green! 

One day the water was green throughout. I've forgotten when that happened.  After a couple of shock treatments, it turned brown. And I had plenty of good advice during that time.  But nothing worked. I stopped swimming.  I was done.

By the end of that summer I had come to the point of deciding that this hole full of water needed to become an ordinary, standard, chlorinated swimming pool.  I was ready to join the other side.

Reflections on the Water

I still believe in the concept of natural pools.  Although I could easily falter.  I've read that they are still popular – although how popular statistically speaking I've no idea – in several European countries.  Some of them must work out just fine, mustn't they?  There is a gigantic public natural pool in Minnesota, the Webber pool in North Minneapolis, that I'd first heard about in 2017.  I checked it out onlline recently to see if it was still working. I learned it has been suffering from a number of recent closures because of poor water quality. (!)  The cited reason is duck poop contaminating the regeneration (i.e., plant) zone.  Little wonder, as regeneration habitats are nothing short of idyllic for frogs, birds, and wildlife in general – as I can testify.

Frogs proliferated in my pond from the start, as did newts and probably any number of other creatures.  Each year some of the frogs tried to overwinter in the pond and not all met with success.  In the spring I have had to fish out four or five dead – and, alas, decomposing – frogs that left me wondering whether they could be somewhere underneath rocks I couldn't see.  Hmmm.  And I often wondered why they would choose the pool to overwinter when an actual pond with a frog-friendly muddy bottom was only yards away.

To make my pool work, it's possible that my regeneration area could have been larger, not just more plants but a larger area of plantings. Maybe the filtration should have been better from the beginning.  Maybe I should have been better schooled in algae control from the outset. Not being smart about these things didn't help.

This is how it looks right now.  I have let everything go:  no filtration at all, no water added (the wood frame should be underwater), no restaining of the deck.  The water is murky and brown, a look only the frogs and the newts could love.

Steps into the murk. turned over to the frogs for now.

When it was good, it was very good.  When it was bad, it was awful.  

*The post was called "Coming Attraction:  A Natural Pool," 5/29/2017