Windscaping: Water conservation through wind deflection
Pity the soccer players of Morgan Hill. When these athletes hit the Soccer Complex in this semi-rural California city located at the southern tip of Silicon Valley, a ceaseless northerly wind from San Francisco Bay will dramatically alter the trajectory of any ball launched into the air.
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Morgan Hill’s swimmers don’t have to worry about throw-ins or punts, yet the persistent regional wind is still a contender at the Morgan Hill Aquatics Center, designed by ELS Architecture and Urban Design and situated south of the Soccer Complex. Besides making for choppy water, “A lot of energy and water usage in pools is lost due to evaporation,” says ELS principal Geno Yun, AIA. “In a windy climate you lose even more water because of the volume of air passing over the water surface.”
“When the city decided to build a swim complex here, the biggest concern was protecting the pool deck from the winds,” Yun says. Upon charting the site’s profile, a wind consultant determined that a 20-foot-tall building would shield 100 feet of pool deck beyond it. Accordingly, the wedge-shaped roof of the pool building—which contains administrative, ticketing, locker, and restroom uses—peaks at that height, and ELS placed it on the northern end of the center’s 8.5-acre site in order to shield the instructional lap pool, waterslides, and children’s sprayground immediately south of it. A separate building housing mechanicals as well as chemical and equipment storage was configured perpendicularly to the main structure, and west of these leisure-time water elements.
The buildings alone do not entirely protect the complex. Exercisers as well as swim and water-polo teams frequent the 50-meter competition pool south of the recreational area. To get the prevailing wind to leapfrog over this portion of the site, ELS conceived a series of slightly canted windscreens, which comprise polyethylene-coated nylon mesh panels anchored to pairs of 30-foot-tall wooden masts. The tension-cable junction of fabric and mast lends itself to sailing metaphors, although the loose mesh was chosen “not to trap the wind but to let it permeate at a lower rate,” Yun says. “It prevents additional stresses on structure and fabric, and it allows the wind speed to slow down as it hits this plane and diverts it.” Despite its translucency, the screen also shades picnickers—another kind of shielding accomplished.
Since the aquatics center opened in 2001, a combination of waterless urinals, drought-resistant landscaping, and ELS’s wind-screening techniques have proven a 40 percent reduction in both water use and pool heating energy costs. It takes 100,000 gallons to fill all four pools, so this savings equates 2.8 million gallons of water savings annually. (Energy usage should plummet further when the municipality can afford to install 6,000 square feet of solar hot water panels on that sloping roof.) And every year that passes, as the Western drought intensifies, seems to further validate these simple and economical water-conservation solutions.
Yun says he’s fielded inquiries about the mesh windscreen, too, but has seen none come to fruition. “There must be a lot of communities out there that have wind—and cost—issues,” he says. “I don’t know if they realize the savings they would reap by investing this little bit more upfront.”
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