The Case For Natural Swimming Pools

photo of James RobynNatural swimming pools/ponds (NSPs) began in Europe (actually in Austria) in the early 1980s. The inventor, Werner Gamerith, was awarded the Austrian Government’s Prize for the Connection between Art and Ecology. This was a prescient insight (rare on the part of government IMHO) into the true nature of the NSP (pun intended). The case in favor of the NSP is encapsulated in that insight — it is an artistic leap forward and it is based in the science of limnology.

The “art” part is pretty easy to see: NSPs are landscape objects and watershapes. They can be works of art when well designed. In fact, as a designer, I feel that they offer far more possibilities than the “traditional, chemical” pools that I’ve been designing for years. Not only do we get to design a swimming vessel, there’s also a planted regeneration zone that becomes part of our work. Formal design can be kept intact in both the swimming and regeneration zones or designs can be a mix of formal and natural. Multiple water levels are frequently embedded in the designs and the natural water imbues a feeling of relaxation and harmony with nature.

But the real case to be made for the NSP is “sustainability.” The pool industry grew up on the concept of “Vacation in Your Own Backyard”. I remember ads from the 50s and 60s, when the pool industry was young, with that exact headline. This approach hasn’t changed in 50 years: our industry is still rooted in “Vacation in Your Own Backyard,” now often called a “staycation.” 

But the times have changed: although the cost of gasoline may discourage people from traveling for a vacation, no longer does it cost just pennies a day to operate a pool pump. We’re also running pool systems that require high-volume turnover and use pressurized filter vessels with poor flow characteristics (particularly multiport valves); even the most electrically-efficient pumps can’t overcome the innate filter design requirements and flaws. Given our technology and eight-hour turnover goals, it’s electrically expensive to operate a pool today.

Similarly, the chemicals that we’re putting in our pools don’t come cheap. Gone are the days when the 100-pound drum of cal hypo (old “scoop and cough”) was the only pool additive we used. Today the mix of chlorinated isocyanurates, shocks of various types, water clarifiers, balancing chemicals for alkalinity, pH, and hardness, algicides for every color of malady (including green algae, black algae, mustard algae, pink slime and white water mold), borates, phosphate removers, flocculants, etc., can be mind-boggling — especially for the consumer.

Consumer confusion about and lack of attention to balancing pool water chemistry easily leads to increased costs from ‘random’ use of inappropriate chemicals, increased costs from damage to the equipment and to the pool itself, increased costs from dealing with out-of-control problems such as chlorine demand (e.g., from extensive algae growth) and metal contamination, and increased costs from adverse health effects including eye and skin damage. 

Since the mid-1980s we’ve known that consumers don’t like chlorine. When the biguanide chemical systems first came out back then, consumers flocked to them when they were told that “it’s not chlorine.”

Fifteen or so years later, we’re seeing consumers now running to the “salt water” pool. The “salt water” pool is often misunderstood by homeowners as being a “chlorine-free or chemical-free” alternative, when in fact, it is a chlorine pool.

There are really two “sustainability” issues in play here.  The first is that the chemicals that we put in our pools are not eco-friendly, environmentally-sustainable economics.  Expensive and damaging to the environment, pool chemicals require the mining of the raw materials necessary for the chemicals, the manufacture of the chemicals in chemical plants, the packaging of the chemicals, and the many steps of distribution and transportation of the chemicals. Each of these components has impact on pollutants, carbon footprint and environmental costs, and yet the ultimate goal is to dissolve the chemicals in the water of our backyard vacation. Ultimately, this cannot be sustainable. 

At some point in the future, hopefully sooner than 50 years (we’ve only really been doing it the chemical way for a little more than 50 years), or 500 years or 5,000 years, it will become accepted that chemically treating pools are too financially expensive and too environmentally damaging to continue as the routine.

There are of course other technologies that can be used, e.g., ozone, ionizers, and ultraviolet light, but notwithstanding a discussion of their efficacy to keep pool water healthy, clear and algae-free, these technologies are also energy consumers. And like chemicals, these systems are used to disinfect or sterilize the pool water, i.e., they are used to kill all of the the life forms in the pool (except hopefully the swimmer).

This brings up the second of the “sustainability” issues.  Is it really necessary to chemically disinfect a swimming pool in order to make it healthy and safe for bathing?

The Natural Swimming Pool embraces the biological processes that occur in nature to produce water that is clear, healthful and consistent with bathers’ expectations.  The science of limnology (a.k.a. the “oceanography” of inland fresh water) demonstrates the biological processes that naturally occur to clarify and purify fresh water in a pond. An NSP cleans water without any chemicals. In an NSP, the water is purified naturally by the movement of the water through filters and the biological functioning of plants and microorganisms: the NSP is a balanced ecosystem where all plants, microorganisms, and introduced nutrients are interrelated to create true “living water.”

An NSP functions optimally when all of the biological factors are present in the correct ratios, which is called stability. In fact, the system becomes more stable with time.

In the regeneration zone, biological principles are at work breaking down undesirable components in the water and transforming them into nutrient for plants. Because there is no soil, plants and microbes must get all nutrients from the water, i.e., the plants and microbes thrive on the nutrients that would otherwise feed unwanted algae growth.

Water flow is naturally an important component of the biological system and also a determinant in the ecological sustainability of a pool. The natural processes that take place in an NSP require much slower water circulation rates than a traditional pool. This results in energy and cost savings. Also, best practice calls for NSP design to function such that gravity is the force bringing water through much of the system, allowing for less pumping and therefore less energy consumption.

The case for natural swimming pools comes down to art and science.  The art of the NSP is immediately apparent and without limits beyond the designers’ vision. Additionally the inherent biophilia (the instinctive bond between humans and other living systems) from the NSP makes it “feel” like a more comfortable environment.  The science of the NSP reflects the proven, effective function of balanced biological processes in stable, sustainable ecosystems.  NSPs are the environmentally and financially responsible choice. 

Next on the Blog - notes and reactions from Germany, July 6-8, 2011 in a visit to a number of residential NSPs.

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