Water: A precious resource
As the most vital feature of all pools and spas, water is a precious resource that deserves significant attention in regards to sustainable design and maintenance. As a general guideline, water features of all types should be designed to conserve water and all other related resources, such as electricity. For example, professionals can work to mitigate any negative impact a water feature might have on natural or potable (drinkable) water supplies. Potable water is a very expensive resource to produce; as such, many water authorities are taking greater steps to protect it. According to the Organisation for Economic Co-operation and Development (OECD), Canadians use an average of 16,000 m3 (565,035 cf) of water per person, per year, a figure surpassed only by the United States. Though many Canadians use natural water supplies as a source of water, the country’s water supply needs have been increasing at a shocking rate, which is taxing expensive water infrastructure systems. One of the most effective water conservation strategies involves estimating the amount of rainwater available on a given site and capturing it for use in a landscape feature, such as a pool or spa. By capturing and using rainwater, the water feature will require less potable water from treated water sources. In an effort to make this process easier, SITES guidelines include calculators to help estimate rainfall amounts and average potable and non-potable water needs of a given landscape. Some of the most common methods of capturing water include the use of roofs and drainage systems, which gather surface water runoff. Water reclaimed and harvested from the site itself can be used in many pool and spa systems, reducing energy expenditures needed to deliver water from outside treatment facilities. While one must always ensure water used in features is of high quality, many advances are being made in small-scale water capture, harvesting and reclamation systems, which can produce drinking water quality results without the need for large-scale water treatment. Likewise, if water features recirculate water back to an external water supply, one must ensure the flow and ecological quality of downstream water systems is not affected.
A more natural approach to pools
Pools may be designed to mimic or even become part of the natural environment. These so-called ‘eco-pools’ can be built to work in concert with natural water supplies and ecosystems, increasing biodiversity and habitat while providing clean, healthy water. When building a hybrid lakeside, oceanside or natural pool that uses only natural source water and requires no supplementary treatment, pool and landscape professionals can also incorporate appropriate plants and biological organisms to the pool’s filtration system. In some cases, plants such as reeds and irises can be used as a natural filtration system, which can be incorporated into the pumping system or act as a passive filtration and solar heating system. If a conventional pool or spa system is more appropriate for a project, professionals can add plants and landscape elements outside the feature to reduce evaporation and promote water conservation. Shading created from strategically planted plants and trees can also discourage algae development and act as a wind-break for exposed sites. Maintenance and treatment of pool and spa water can also have an impact on the health of the environment and the people using the amenities. If there is no natural water body around to act as a source, traditional pool systems can be switched over from chlorine or bromine to saltwater. Saltwater pools help keep water clean and algae-free with minimal maintenance requirements and less strain on the environment and human health. If extra water treatment is required, thermal or ozone treatment systems can be considered, along with chlorine-free additives, which use enzymes to treat algae by removing nutrient imbalances. Regardless of what pool or spa chemicals are being used in the water, pool, spa and landscape professionals should always use precaution when disposing of water. Avoid dumping any treated pool and spa water into the landscape or other open bodies of water—local plants and other organisms can be negatively affected by chlorine, bromine and salt. Pumping systems are likely one of the most energy-intensive components of any pool and spa. When choosing a pump for a project, one should look for an energy-efficient model that supplies the appropriate amount of power. Even a relatively small pump can consume a lot of energy, but advances in design and efficiency can provide more control and assurance that the system is running optimally. Many pumps now have multiple speed settings, which operate at different rates according to usage, which also generate energy savings. By adding a timer to the pump, variable-speed units can be further optimized. These timers are similar to those now commonly attached to building heating and cooling systems.
Conclusion
As the demand for ‘green’ technology increases, more products and support for sustainable pools and spas will undoubtedly appear on the North American market. As pool, spa and landscape professionals need some help on determining a sustainable approach to a project, SITES has a publication called The Case for Sustainable Landscapes. While this was designed for the non-professional, this document explains the larger concepts and importance of sustainability for all aspects of landscape design, material selection, water efficiency and maintenance. It also shows how sustainable strategies can also result in positive economic benefits and cost savings for all involved.
Melanie Sifton is the director of Humber Arboretum & Centre for Urban Ecology in Toronto. She has been working with the Sustainable Sites Initiative (SITES™) team at Lady Bird Johnson Wildflower Center in Austin, Tex., toward the formation of guidelines and performance benchmarks for sustainable landscapes since 2008. Sifton is a graduate of Cornell Plantations public garden leadership program where she focused her research on sustainable landscape design and operations in public gardens.
