Water-conserving landscaping is no longer reserved for dusty front yards in Southwestern states, where sparse rainfall undermines even the most determined gardeners’ efforts to coax lush, green lawns from the thirsty loam.
As more developers and landscape architects foresee water shortages for even historically rain-rich regions, they’re designing private lawns and common spaces with deep-rooted native plants that thrive with minimal watering. And they’re investing in computer-regulated irrigation devices that deliver the precise amount of moisture needed to sustain each plant—and not a drop more.
Nancy Somerville, CEO of the American Society of Landscape Architects, notes that Atlanta came within about 90 days of running out of water in summer 2007, and in Boston, the foundations of some older buildings are threatened as more groundwater is removed to hydrate a growing population.
“Certainly, there was a wake-up call last year in the Southeast, which hadn’t been used to dealing with water shortages,” says Alex Wilson, executive editor of Environmental Building News and president of Building Green.
“In Houston, water is not an issue in its availability,” says Michael Strong, vice president of Houston-based GreenHaus Builders. “Water’s cheap in Houston; we get a ton of rain. The big deal is it’s not going to be that way for long.”
Smart Growth
Water-conscious builders—and many green building certification programs—rank landscaping practices that minimize the need for outdoor watering at least as high as “smart” irrigation controllers, water-permeable paving products, and systems that capture rainwater or recycle greywater from a home’s showers and sink drains. But a true water-conscious plan includes elements of each strategy.
“Limiting the need for irrigation should be the first concern,” says Matthew Nielsen, development manager for Windermere on the Lake, Connecticut’s first planned community of LEED-rated luxury homes.
First on a landscape designer’s plan, then, should be drought-tolerant native plants, which thrive with whatever rain falls in a local area, and as little thirsty, shallow-rooted turf as the homeowner can tolerate.
“We encourage people to rethink what’s beautiful,” notes Maureen Mahle, program manager of LEED for Homes at Steven Winter Associates, a building systems consulting firm. “Homeowners are more open to [less turf and more native plants] than builders tend to recognize.”
“Minimizing the lawn is a big part of this,” agrees Somerville. “The least lawn space, the better.”
Another tactic: small trenches around gardens and dips in the topography that cause rainwater to puddle around plants with roots that can tolerate it. This helps keep moisture from running off the lawn and into sewers, leaving it to soak into the ground.
“The key to conserving water on the outside in the landscaping is, No. 1, the way you create the lots so you retain the natural rainfall … as long as possible before it falls off,” agrees Arizona builder John Wesley Miller.
Go With the Flow
Following smart layout and careful plant selection, products designed to further conserve and better manage water on the property also come into play.
Creating a yard that requires little watering lets a homeowner or even a developmentwide landscaping service get by using captured rainwater to keep plants healthy instead of potable, irrigated water. Rainwater catchment systems harvest runoff from roofs and gutters into barrels that are connected to hoses and pumps, which stand in for an irrigation system that relies on city water. Rain barrels range from large vessels with attached garden hoses to underground cisterns that work in tandem with a sophisticated distribution system.
To earn points toward LEED certification, a cistern would have to catch at least half of a home’s roof runoff and include a pump, which can be put in the home’s basement.
Another technique is the distribution of greywater, or water collected from household drains (not the toilet) that can be reused for landscape irrigation (see “Grey’s Anatomy,” left)—although it’s one that builders and some jurisdictions are not warming to quickly. (Some cities and states will not grant permits for new construction or remodeling projects that include greywater reuse because of concerns that greywater contains bacteria and chemicals that people, and even pets, might come into contact with.)
For the parts of the landscape that do need regular watering, water-conscious builders rely on drip irrigators that slowly wet only the plant that needs attention rather than spraying water over a whole lawn, often including trees, porches, and driveways. Drip irrigators are rigged to timers to deliver a precise amount of water on a schedule that eliminates unnecessary watering.
The newest irrigation systems are so “smart,” they can sense whether it has rained and how much, and will skip a scheduled watering if it’s not needed. They are programmable to recognize the type of plant being irrigated and to deliver the specific amount of water that species needs.
Stopping Power
Just as important to a landscape design is controlling storm-water runoff from paved areas, which can take with it excess chemicals and sediment.
A low-tech way to direct rainwater back into the soil instead of out onto the street and into storm drains is to hardscape with permeable paving materials. Unlike blacktop, these materials let water percolate down through joints between the pavers or through pores in them.
Likewise, plantable pavers are designed with openings through which the landscaper can plant grass.
Builders in Richmond, Va., may cover no more than 16% of their home sites with nonpermeable surfaces like concrete sidewalks or asphalt driveways—and the house itself—that prevent rainwater from soaking into the ground.
Builder Lloyd Poe, owner of LifeStyle Builders & Developers in Richmond, says as lot sizes get smaller, he will line the alleyways behind new rear-loaded homes with permeable pavers.
“It’s a greener way to build,” he notes, “and by doing that, you can build a bigger house.”
Regardless of method, Miller says builders are in the best position to change the water-wasting habits of their home buyers. “We can have a major, positive influence,” he notes. “It’s not too late to change. ”
Sharon O’Malley is a freelance writer in College Park, Md.
Grey's Anatomy
Greywater is household waste water that has rinsed down a sink or shower drain or poured out of the washing machine or dishwasher. It’s “cleaner” than the “blackwater” used in toilets and in sinks with garbage disposals, so some jurisdictions allow homeowners to recycle it for irrigating their lawns and plants.
The practice is sanctioned in only a handful of states, and some local building officials refuse to grant permits for new construction or remodeling projects if the plans include greywater recycling. Contaminants in household waste, such as chemicals, soap, and fecal matter, officials fear, will cause bacteria to grow and spread diseases.
Areas that allow the use of greywater for landscape irrigation typically restrict its delivery to a few inches under the soil’s surface, so people and animals won’t come into contact with it.
Resources
Florida Water Star Program: www.sjrwmd.com/floridawaterstar
WaterSense (EPA): www.epa.gov/watersense/pp/new_homes.htm
Water Use It Wisely: www.wateruseitwisely.com
WaterWiser (American Water Works Association): www.awwa.org/Resources/content.cfm?ItemNumber=29269&navItemNumber=1561
HydroPoint. The WeatherTRAK evapotranspiration controller automatically adjusts irrigation schedules based on landscape needs and local weather conditions. WeatherTRAK eliminates landscape overwatering and saves four times more water than any other technology, the maker claims. The device draws on information delivered wirelessly from 27,000 weather stations to automatically schedule irrigation based on the outdoor temperature, how much it has rained, and how much water each plant needs. 800.362.8774. www.weathertrak.com.
Rain Bird. The Gardener’s Drip Kit includes all the connections, tubing, emitters, and tools necessary to install the drip irrigation system to an outdoor faucet or an underground irrigation system, the manufacturer says. Once installed, the system will distribute water slowly and consistently direct to the plants’ roots, helping them thrive while using less water than a conventional irrigation system. The drip places water directly on the soil above the plants’ roots, letting the water soak down to the roots—reducing runoff and eliminating water waste, the company says. The kit is a reengineered version of the company’s professional-grade drip components, so it is easier to install, the firm says. 800.724.6247. www.rainbird.com.
Pine Hall Brick. The manufacturer’s permeable brick pavers enable storm water to filter into the soil instead of draining into streams and rivers, and satisfy state and local storm-water management requirements, the maker says. The company says its pavers are easier to install than some because there are only slight variations in size. The clay brick pavers are the same color throughout, so they never fade, the firm says, and once in place, they will last more than a century. 800.334.8689. www.pinehallbrick.com.
Aaron’s Rain Barrels. The manufacturer’s irrigation rain barrels are made from 20 pounds of recycled plastic or 110 pounds of oak, brass, and steel. The barrels have two spigots and connect directly to a home’s rain gutter downspouts. A removable zinc irrigation spigot can attach to a regular garden hose and has a shut-off value so the homeowner can leave it open for drip irrigation. The 58-gallon plastic rain barrel is fully enclosed for safety. The company’s wooden whiskey barrels (pictured) are reclaimed from Kentucky distilleries. 978.790.1816. www.ne-design.net.
Netafim. Bioline Dripperline disperses waste water through a drip-irrigation system. The flexible tubing delivers a slow, steady application of water directly to plants, eliminating overspray, staining, and slippery surfaces, the manufacturer says, and reduces water use 30% to 70% compared with sprinklers. The system’s modular components allow for a flexible design that can reach oddly shaped and hard-to-water areas, and can disperse from a few hundred gallons to millions of gallons of water per day, the company says. 888.638.2346. www.netafimusa.com.
Soil Retention. Drivable Grass consists of tilelike, 2-foot-by-2-foot concrete squares connected into a mat by a grid system. Landscapers can plant grass through lattice-style holes and cracks that let roots penetrate through the mat into the soil, anchoring it firmly into place, the manufacturer says. The mat’s porous nature enables moisture to filter into the underlying soil, reducing runoff while allowing water to be absorbed on site. 800.346.7995. www.soilretention.com
Belgard. The company’s permeable pavers are made of concrete and separated by joints filled with small stones. Water enters the joints between the pavers and filters through crushed stone layers; the water, minus the filtered-out pollutants, is absorbed into the soil. The pavers can be used for patios, driveways, walkways, pools, and other areas. The manufacturer says its pavers, including Subterra stone (pictured), allow for modular and random installation to create random patterns that look like natural cobblestones. The product comes in multiple shapes, colors, and patterns. 800.899.8455. www.belgard.biz.
Clivus Multrum. The Clivus Greywater System includes a Greywater Dosing Basin as the collection point for all of a home’s greywater. Made of rigid plastic, it contains level switches and an effluent pump or gravity siphon (where sufficient slope is available). When an amount of greywater sufficient to create a 11/2-inch flooding dose within the irrigation chamber has collected in the dosing basin, the pump (or gravity siphon) engages. Because the irrigation chamber is flooded throughout its length, water and nutrients are carried evenly to surrounding plants. 800.425.4887. www.clivusmultrum.com.
Toro. The LawnMaster II Timer features three program options and meets the requirement of communities for multiple-option timers during watering restrictions, the manufacturer says. A large LCD screen, a programming dial, and selection buttons let users choose which days to water and how long each zone will be watered. In addition, the user may activate a single watering area or start any watering program right away without waiting for its scheduled time. A sensor shuts off the irrigation system if it rains. The device is available in four- and six-zone models. 800.367.8676. www.toro.com.