 Two views of a natural swimming pond designed by Ken Schoen of Waterscapes. The 40,000-gallon pond features a wraparound deck with waterfall and underwater lighting. |
Bringing water home for our personal enjoyment is the coup de grace in home landscaping, and swimming pools have gone from being the province of princes in ancient times to becoming within reach of just about everyone in the modern era. There have been many innovations in pool design in the past five decades, including Gunnite construction, kidney shapes, waterfalls cascading from spas, 'invisible edges,' and edges studded with boulders and ornamental grass plantings. Each advance seems to be an attempt to make the pool approximate nature more closely. But recently, from "across the pond" in the UK, comes the most accurate approximation of all—a natural swimming pond, which has the benefit of being garden water feature, wildlife habitat, and a refreshing pool for swimming rolled into one.
In Europe and Australia, natural swimming ponds have been built by specialized companies for years. Of the tens of thousands of pools installed in the US, only a few have utilized this model, but the trend is on the rise. With its waterlilies and attendant dragonflies and wildlife, the natural pool is visually delightful, looking and feeling like a naturally occurring pond, and with its lack of pool chemicals, it is surprisingly low maintenance as well as environmentally sustainable..
For most natural pond owners and builders, like Jay Archer of John Jay Land Management (www.landdesign.net), aesthetics and ecology are the prime motivation to go natural. The natural pond is, after all, alive, not static. With the wildlife the pond attracts, it is more interesting than a pool, always changing. Whereas swimming pools use chemicals to kill everything except the swimmer, natural swimming ponds maintain pristine water utilizing natures own processes to create an ecologically balanced system, while reversing wetland habitat loss which has resulted from unenlightened development.
Ken Schoen, of Waterscapes in Kingston (www.koiponds.com), agrees with Archer's assessment of the deathlike quality of conventional pools. "What you're doing with chlorine is poisoning the water," says Schoen. You're turning it dead," says Schoen. "It's not like when you go into a natural pool, because it has bacteria it's bad for you. A natural pool is like yogurt—there's plenty of good bacteria in there." Schoen, whose main focus is on the design of water features like koi ponds, streams, and waterfalls, also believes one of the main reasons consumers choose natural pools is the way water features easily integrate into the natural space of the backyard, as opposed to the rigid, (usually) rectangular artificiality of a swimming pool.
Ten years ago Bert and Sue Holmes, who have a 70-acre parcel of land near Cooperstown, created a secluded 2,000-square-foot pond on a rise above their 1890s Victorian home. Over time, they added a tiny cabin with a sleeping loft and woodstove for camping out, and a brick barbeque for the annual summer parties they hosted. With its diving dock and amble size for rafts and swimming, the Holmeses' pond became a magnet for the summer activities of their three sons and their friends.
The Holmeses built their pond for about $8,000 using an excavator with experience building ponds, and soil maps from the Cornell Cooperative Extension. The pond is both stream-fed and supplied by natural springs. The soil was found to be marginal: not an optimal clay soil, but with enough clay content to hold form and water, and though the area is generally stony, there was no ledge rock which can contain pockets that leak water. Bert says the only maintenance is to declog the overflow occasionally, which consists of a dam over which water flows out, keeping the water on the move and constantly fresh. The pond is stocked with rapidly multiplying goldfish, chubs, yellow perch, and channel catfish. Minnows, frogs, and cattails have naturally found their way to the pond as well as several species of fish that have arrived as eggs on the feet of heron and ducks, who, in an elegant example of reciprocal maintenance, keep fish populations in check by feeding. At 16 feet deep, the pond stays cool throughout the summer. Sue says they chose to make a swimming pond because "there's no maintenance for us. There's no added expense. Plus, we could make it four times as big as a swimming pool for less money".
Not all of us are lucky enough to have natural springs and streams feeding our land, so most swimming ponds are constructed using heavy (45-millimeter) liners, and pumps to circulate water. Ledges or slopes at the edge of the pond are home to water plants introduced to act as biological filters, eliminating the need for chlorine or other chemicals.
Cost estimates vary greatly depending upon the size of the pond, the difficulty of the site, and how much of the work you do yourself. The cheapest approach is to do it yourself—perhaps with a little help from the experts—by digging a hole with sloping sides, at a ratio of one foot vertical drop for every three horizontal feet. Unless you have the right soil, you'll need to add a liner, available from garden centers specializing in pond construction. Under the liner are layers of sand, newspaper, and an underlying layer of carpet or woven fiber to protect the liner from stones or roots protruding from below. The liner is secured above the high water line with soil or stone. Another possible option is the addition of bentonite clay or a synthetic version to bond soil particles and prevent leakage. However, a synthetic rubber liner of ethylene propylene diene monomer, or EPDM, offering superior UV protection, is the method of choice for ease of installation and flexibility.
In a natural pond, the planting and swimming zones are distinct. Plants can be floated on the pond surface and marginalized around the edges. The goal is to create a balanced, self-maintaining ecosystem. Water chemistry is a complicated science and all ponds will differ according to runoff, rain, airborne pollutants, and the presence of fish among other factors, but change within an acceptable range is expected. The roots of water plants act as a natural bio-filter, clarifying and decontaminating the water. Fibrous roots contain bacteria which filter contaminants and excess nutrients to prevent algae, and decomposers to consume bacteria and underwater waste build up. The shallow plant zone is heated quickly by the sun and provides a breeding ground for frogs and other invertebrates which feed on mosquito larvae. Keeping the water moving with an electric pump makes the filtration constant and at the same time provides oxygenation for water organisms.
Additional equipment for larger ponds can include compressors, aerators, and skimmers to remove leaves and debris, which change the pH of the water as they break down. To control erosion, and create a natural looking edge, plant stone and marginal plants around the perimeter. Waterlilies and lotus flowers, which are available in hundreds of colorful, hardy hybrids, can be floated in deeper areas.. On a trip to Wave Hill Gardens in the Bronx last fall, I heard a docent remark that her favorite plant in the water garden was the mosaic plant. Wondering what it could be, I searched until I spotted the one deserving of the name, with its unmistakable leaf configuration on the surface of the water.
Unlike a traditional pool, a natural swimming pond provides four seasons of beauty and a habitat for wildlife, and it doubles as a fish pond and water garden. It requires filling only once and requires no chemicals or maintenance crew, resulting in a more economical, sustainable pool. It can be as large as space allows without breaking the bank, and blends seamlessly into the landscape for a cooling dip or some serious exercise in an idyllic oasis.