Cleaning My Swimming Pool Is Like Building Strong Towns

Image via Flickr.

I never thought I'd be the type to own a swimming pool. Too much work, and besides, I'm a public parks kind of guy who grew up taking swimming lessons at the neighborhood municipal pool. But when in Florida, do as the Floridians do, so ten years into living down here, I finally took the plunge and got the bare minimum version: an assemble-it-yourself, above-ground pool 15 feet in diameter.

All was well until we went away for a month to visit family. Although we instructed a friend to do the basic routine maintenance (no special troubleshooting), we got home, and the pool was green. Like, ninja-turtles-might-pop-out-of-it green.

The following few weeks were a frustrating but kind of fascinating lesson in a key fact about systems thinking, and the reason I'm writing this piece:

Maintaining a healthy system in a stable equilibrium is relatively easy.

Restoring an unhealthy system back to equilibrium is very hard.

A truth at the core of the Strong Towns approach is that cities are complex systems, in which millions of individuals and institutions make decisions that all affect each other, and causes and effects are difficult to discern, let alone accurately predict.

Tortured-metaphor alert here, before I begin torturing it: A city is of course not a whole lot like a swimming pool. Human agency is far more complex than anything algae have figured out how to do. Nor is a backyard pool really a complex system in the way an ecosystem is. It's a simplified version of one, in which the chemistry can be reduced to a countable number of variables that are understood—and as for biology, if there's much biodiversity in a pool, well, that means you dun screwed up. 

But complex systems thinking is hard to communicate in writing, and for that, a simplified metaphor is perfect. 

I had it in my head that I'd buy a couple chemicals, treat the water, kill the algae, and be back to normal in no time.

Instead, getting back to clear, clean water was a three-week ordeal of dealing with not just the algae, but chemical attributes like the alkalinity and pH, water hardness, and so forth. If any of these things is out of the right, narrow range, the system as a whole might not be stable.

And fixing one thing repeatedly seemed to alter something else. I was instructed by my friendly local pool supply store to use an enzyme solution to remove dead algae after shocking the water with intense amounts of chlorine for 36 hours. The problem? Chlorine itself rapidly kills the enzymes that clean up the algae. So, I added a chlorine neutralizer to the pool, but used too much. Then ensued a week in which I couldn't get the chlorine levels back up, and the algae began to return. Back to the store for a non-chlorine shock, which tends to affect the pH, so add to that some soda ash. Certain chemicals also only work if you add them in the right way, such as just after brushing the pool walls with a stiff brush.

So what's the point here? Simply maintaining a pool with healthy water chemistry involves as little as 10 minutes of maintenance a week. Bringing a pool back to healthy water chemistry, on the other hand, is a frustrating process in which things affect other things, and the system doesn't always behave the way the package directions for this chemical or that one say it should.

Image via Flickr.

Getting Back to Easy

A common lament of those who feel that traditional, pre-car urban design serves human needs better than many of the places we build today is the effort involved in any attempt to replicate those time-tested forms. And yet, societies far poorer and technologically less sophisticated than our own didn't only build places that are still beloved today, but in some cases built them at a blistering pace. "If they could do it, why is it so hard for us?" 

One answer, far from definitive but helpful nonetheless, is provided by our metaphor: they were working with a clear pool. We're starting with a murky, green one.

Today, you can do a beautiful, human-scale street that accommodates a lively mix of activities, but it's not going to be a cheap or easy way to build. And sometimes the reasons it's difficult overlap in frustrating and confusing ways. It's not just the zoning: it's also the building code. It's not just the building code: it's also the financing. It's not just the financing: it's also the cost of construction labor and materials. It's not just that: it's also the cost of land. Ask a development expert about how to overcome these barriers, and they'll often just shrug and say, "That stuff's hard. It doesn't scale well, and the economics don't usually work out."

The status quo is failing to "work out" in other ways, though. The systems that govern our development pattern are distorted, and you can't disentangle one distortion cleanly from another. On top of that, our cities are measurably unhealthy. We see it in:

• Crumbling infrastructure, with growing maintenance backlogs.

• Pervasive housing affordability crises.

• Growth in concentrated poverty and income segregation.

• Consolidation of retail, with the loss of local entrepreneurs and dominance of chains.

• High rates of obesity, asthma, and other public health problems.

• A crisis of unsafe streets, including pedestrian deaths up 50% in only a decade. 

But from a systems perspective, our current development pattern isn't really like that murky green pool. (Come on, don't stretch your metaphor too far, Daniel.)

In fact, our predicament is much worse. How complex is a pool, really? The water is affected by organic contaminants that get in, but it's a fairly contained environment. The number of variables isn't that great. 

In a complex system, on the other hand, we're talking millions of variables. Causes and effects that are quite impossible to trace. We can measure outcomes we care about quantitatively, and we can often observe mathematical relationships that seem to govern them. But that doesn't mean there's a simple answer to how to restore them to the level we want.

Conservation biologists know this well. Ecological restoration is not easy or fast work. And unlike when your swimming pool is full of algae, you don't get to go nuclear—the first thing they told me to do to my pool was to put so much chlorine in it to kill anything alive in that water. There is no equivalent to that for restoring equilibrium to a system where life is, you know, the point. 

Instead, there's painstaking work intended to create little beachheads for good things that can then spread and reproduce on their own. There's invasive species removal to do, too. But it's typically surgical, or else the collateral damage would be too great.

I've argued before that planners should basically be the conservation biologists of cities. Our goal is to recognize when things are out of whack and trace some of the feedback loops involved, and to propose interventions that can begin to set things straight. They might be localized placemaking efforts meant to plant a seed. They might also be policy changes, like to the tax code, that are the loose metaphoric equivalent of altering the pool's chemistry to make it inhospitable to the invasive things you don't want there.

But those interventions can't be massive infusions of force and capital, or we just end up seesawing from overcompensation to overcompensation, from solving one problem to creating three more.

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