HEM July/August 1994 - Home Energy Magazine Online July/August 1994

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Home Energy Magazine Online July/August 1994

WATER

Xeriscape: Winning the Turf War Over Water

by Lisa Iwata

Lisa Iwata is a landscape architect based in San Clemente, California, and is on the California Xeriscape Foundation's Board of Directors.

While xeriscape may conjure visions of rocks and cow skulls in some minds, xeriscaping principles can produce beautiful, functional, and resource-conserving landscapes.

Xeriscaping is a resource-efficient approach to landscaping that emphasizes good planning, region-appropriate plants and efficient water management. A well-planned landscape can save water and labor; create an oasis away from life's stresses; provide habitat for wildlife and preserve plant species; and improve property values. When water travels from river to house to sewage plant, energy is used to pump, treat and heat it. Saving water therefore saves energy too.

Xeriscape (from the Greek xeros, for dry) was originally defined as "the conservation of water through creative landscaping" by the Denver Water Department, which created the moniker for an educational program in the early 1980s. In 1983, several industry professionals in Orange County, California implemented a similar educational program and hosted a statewide conference. Over the next several years, programs began to spring up around the country--in Austin, Texas; Marin County and San Diego, California; Phoenix and Tucson, Arizona; southern Florida, and Oahu, Hawaii. Today, many city and regional water agencies run xeriscape programs and even the landscaping industry is beginning to use terms such as sustainable, resource-conserving and efficient--all of which are synonyms for xeriscaping.

The xeriscape recipe for a resource-efficient and beautiful landscape includes

A New Landscape

Xeriscaping has evolved into more than just a way to save water. As baby boomers settle into busy family lives, and empty nesters feel the time crunch of two working spouses as well as changing landscape needs, more and more people are finding that traditional, high-maintenance yards are not what they need. In addition to these lifestyle changes, increasing public awareness of dwindling resources, rising energy and water costs, limited water availability and poor water quality in some regions, disappearing natural areas, a trend toward smaller, more urbanized housing sites and landfill problems, are all conspiring to change the way we think about our yards.

Traditional "lawnscapes" generally include a front-yard lawn, a shrub border, a few trees, and some flower beds. Rear and side yards often consist of turf and trees and perhaps a patio. Gardens are designed for tradition and social conformity, rather than function and aesthetics. Many people want a front yard just like their neighbor's, and a turfscape is quick and easy. The sod is delivered, rolled and and pressed down, and with the addition of a few trees and shrubs, over a weekend you've got instant landscape.

But grass lawns are actually quite expensive when the cost of the resources, water, fertilizer, pesticides, fossil fuels and labor required to maintain them are factored in. From a use point of view, though, there really is no substitute for turf for play, sitting, or picnicking. Where lawn is essential, take care to pick the proper variety for the region and climate and consider the new drought-tolerant, low-maintenance turf varieties such as Buffalo grass, turf-type dwarf fescue, and Bermuda hybrids. Avoid using turf on steep hills and narrow, difficult-to-water areas such as parkways and medians. Good soil preparation and water management are critical to efficient lawn maintenance.

While the verdant open space provided by a lawn will probably continue to hold a place in most peoples' hearts, others are deciding that they don't really need so much turf in their yards. As resource and time budgets become more constrained, many are opting to exclude or limit this costly item.

As a landscape architect, I examine a client's needs and desires, helping them decide on the best design for their lifestyle. Homeowners today are asking for fruit and vegetables in the yard, more varied spaces and patios, outdoor entertaining and lounging areas, spaces for play equipment, trees or shrubs to enhance or screen views, and sometimes turf. More people seem to want a natural or semi-wild look, bringing nature back into their lives and at the same time minimizing maintenance.

The Cactus Syndrome

Xeriscapes do not have a single "look." Though the news media has often portrayed xeriscapes as rock, cactus, and sagebrush, xeriscapes are as varied as the regions they're found in. Almost any landscape style can be achieved, depending on the region. I have designed English, Japanese, mountain, desert, Mediterranean, and natural xeriscapes.

Once a thorough analysis of the site is completed, and uses and style decided upon, it's time for plant selection. Plants can provide shade, color, texture, contrast, fruit, fragrance, and structure. Proper selection and clustering of plants with similar watering and light requirements are critical to a successful and efficient xeriscape.

Xeriscape designers tend to use a broader variety of plant material, including more native plants which should be used when possible, to promote a regional identity, enhance wildlife habitat and preserve disappearing plant species. While some regions of the country traditionally use native or indigenous plants, temperate western gardens tend to be a hodgepodge of plants imported or transplanted from may regions of the world, with little regard for their origin or placement in the garden. Plants from wetter climates require much supplemental watering (as much as 30 or more inches per year). Save the resource guzzling but prized "imports" for highly visible areas such as entries and patios where they can be grouped, pampered and appreciated.

In a xeriscape, greater care is given to the plant's importance as part of the overall design and functionality of the landscape. Selecting plants for their ultimate size is the key to minimizing costly and labor intensive pruning. Don't place plants in a space too small for them, and allow plenty of space between plants. Plants that are crowded, or pruned too frequently often develop diseases and weakened limbs, leading to the need for pesticides, or eventual removal. Less pruning allows a more carefree "get back to nature" appeal and the results are enchanting!

A well-designed irrigation system is critical to efficient watering of plants. The irrigation industry has been an early pioneer in the water conservation movement. Efficient equipment on the market includes sprinkler heads with or matched precipitation rates; variable arcs; micro or drip, trickle and mist systems; electric controllers (some solar operated) with independent, multi-start, and variable programs; efficient, friction-reducing valves; tensiometers, rain shut-off valves and computer-controlled mega-irrigation systems. In addition, new advances and standards are being developed for both reclaimed water in commercial and municipal applications and graywater (washing machine wastewater, and so on) in residential applications. Rainwater collection and storage techniques are also being re-examined. An efficient irrigation system design is essential to saving water, and can eliminate erosion, pavement losses, and algae problems in gutters and on sidewalks.

Good maintenance is as essential to xeriscaping as it is to energy management. Whether the project is a retrofit or new design, even the most perfect plan will fail if not properly maintained. Over-watering, watering at the wrong time or for the wrong duration, bad pruning, and many other practices can contribute to its failure.

Xeriscape Does it All

It is not enough to save resources--landscapes must also be both useful and attractive. If you are replacing the lawn, you don't merely substitute a drought-tolerant ground cover for turf, you consider the real function of the space, and perhaps even create a whole new use for it. Entry walks, courtyards, outdoor rooms and screening can replace the unused space left by the turf, returning valuable open space to the owner.

Because a xeriscape is well-planned, it can save more than just water. Better planning, plant selection and placement means less pruning and plant removal. A smaller lawn uses less fertilizer, less fossil fuels, and it produces less air and noise pollution and fewer clippings to dispose of. Soil conservation ensures healthier plants, fewer amendments and imported topsoils, and less soil moisture and topsoil losses.

Broadening Horizons

The concept of xeriscape continues to expand. In addition to the original seven guidelines established more than a decade ago, designers of xeriscapes today consider many more elements, including:

Why Lawns Guzzle So Much Water

In semi-arid areas with little or no contributing rainfall during the growing season (typical of most Sunbelt states in the West and Southwest), lawn watering accounts for most outside residential water use. Turf irrigation generally averages 40% of annual residential water demand, and according to John Olaf Nelson of the North Marin Water District in California, this portion can top 60% in peak months.1 Why does turf need so much more water than other landscape materials? The answer is in the roots, the efficiency (or rather inefficiency) of irrigation systems, and in how water is applied.

Common turf planting and follow-up maintenance practices do not promote extensive turf root growth. Even when properly planted, frequent and uniform irrigation is required to keep turf looking green. If water can't be applied uniformly, some turf must be over-watered to compensate and keep the whole lawn green. If the turf is not properly aerated to optimize infiltration or if it becomes thick with thatch due to clippings or abundant surface rooting, the problem gets worse.

Irrigation systems do not usually accomplish high uniformity on the small turf plots found in most residences. Sometimes twice as much water must be applied to compensate for a small-scale irrigation system's inability to distribute water uniformly. Typical residential systems apply water to turf at five or six times the rate that the turf and soil can absorb it. Since sprinkler systems apply water too quickly for most soils to absorb it, water is wasted through runoff.

To optimize a lawn's irrigation efficiency, Nelson recommends:

Note

1. See "Why Turf Requires So Much Water," by John Olaf Nelson, North Marin Water District, 999 Rush Creek Place, Novato, CA 94945. Tel: (415)897-4133.

Strategic Tree Planting

Proper placement of shade trees can save up to 40% on home cooling costs, depending on the climate and design factors. Trees can also provide a buffer from chilling winds and thereby reduce heating costs. Important factors in selecting and locating the right trees and shrubs include type, quantity, orientation, and the height and color of the structure. Trees should be selected for ultimate size, climate preference, safety and aesthetics. Placing trees on the south or southwest side of a structure provides year-round shade. If the trees are deciduous (lose their leaves in winter) then it will allow the sun's heat to actually warm the structure during the colder seasons. If the main axis of the structure faces west, however, trees placed in a southwest to northwest location will provide more shade in summer, when it is probably needed most. Many utilities offer rebates to homeowners who plant shade trees. Watch for an in-depth look at trees as an energy conservation measure in a future issue of Home Energy.

Landscape Water Consumption Comparisons

In a 1992 study, the East Bay Municipal Utility District in northern California compared the daily water consumption of a group of single-family detached homes with "water-conserving" landscapes to consumption by homes that had "traditional" turf-oriented landscapes. Objectives included developing criteria for classifying residential landscapes as "water-conserving" or "traditional," quantifying the amount of water saved by water-conserving landscapes, and determining how lot size, turf-to-yard ratio, and irrigation type affect residential water consumption.

The water-conserving landscapes contained well-maintained vegetation, with turf area less than or equal to 15% of total yard area. By comparison, turf area in the traditional yards was equal to or greater than 70% of total yard area. The water-conserving landscapes saved an average of 42% or 209 gallons per day over comparable traditional landscapes (see Table 1). Not too surprisingly, water use increased with lot size and with increases in the area of turf used in the landscape (see Table 2). Similar studies conducted in Austin, Texas, and by the North Marin Water District in California, found a 43% savings. The North Marin study looked at seven developments consisting of 548 dwelling units with mature landscapes. The sample was divided into two segments: traditionally-landscaped projects, and projects that met specific design criteria for water conservation. When costs for water, labor, fertilizer, fuel and herbicide were considered, annual savings of $75 per dwelling unit were realized for the water-conserving projects. Compared to traditional yards, the water-conserving landscape averaged 55% less turf area, 21% more nonturf area, used 54% less water, saved 25% in labor costs, 61% for fertilizer, 44% for fuel, and 22% for herbicides, with a total of 10% less total landscaped area.

Table 1. Water Conserving versus Traditional Landscapes (gallons per day)

                                       LOT SIZE (IN SQUARE FEET) 
                                    Less than      6,000-     10,000-     Above 
                                      6,000       10,000      20,000     20,000
_______________________________________________________________________________
Water-conserving landscape             170          298         419        656     
Traditional landscape                  278          510         735       1,531     
Water savings                          39%          42%         43%        57%

Table 2. Landscape Water Use by Percentage Turf (gallons per day)

                                 PERCENT TURF
Lot Size (ft2)     <70     70     75     80     85     90     95
Less than 6,000    169     -      -     284     -     274     279     
6,000-10,000       297     -     656    488    516    491     539     
10,000-20,000      418     -      -     620    758    735     817     
Above 20,000       656     -      -      -      -      -       -
Xeriscape Resources

East Bay Municipal Utility District, Richard Bennett, Water Conservation Office, P.O. Box 24055, Oakland, CA 94623 Tel: (510)287-0590; Fax: (510)287-0325.

California Xeriscape Foundation, c/o Watling Company, 51 Alpine Village, Mountain Center, CA 92561. Tel: (619)349--3292; Fax: (619)349-8502.

Department of Water Resources, Marsha Prillwitz, Office of Water Conservation, State of California, River City Bank Building, 1020 9th St., 3rd Floor, Saramento, CA 95814. Tel: (916)327-1620; Fax: (916)327-1815.

North Marin Water District, John Nelson, 999 Rush Creek, P.O. Box 146, Novato, CA 94948. Tel: (415)897-4133; Fax: (415)892-8043.

EOS Institute, Lynn Bayless, 580 Broadway, Suite 200, Laguna Beach, CA 92651. Tel: (714)497-1896; Fax: (714)494-7861.

Xeriscape San Diego, Jan Tubiolo, Otay Water District 10595 Jamacha Boulevard, Spring Valley, CA 92040. Tel: (619)670--2290; Fax: (619)670-2275.

City of Boulder, Water Conservation, P.O. Box 791, Boulder, CO 80306. Tel: (303)441-3251; Fax: (303)441-3259.

South Florida Water Management District, Bruce Adams, Office of Government and Public Agencies, 3301 Gun Club Road, West Palm Beach, FL 33406-3089. Tel: (407)686-8800; Fax: (407)687-6010.

City of Phoenix, Water Conservation Office, 455 N. 5th St. #7, Phoenix, AZ 85004. Tel: (602)261-8367; Fax: (602)495-5843.

City of Austin, Lynn Chaumont, Xeriscape Program, Two Commodore Plaza, 206 E. 9th Street, Austin, TX 78701. Tel: (512)499-3514; Fax: (512)499-2846

Texas A & M University, Doug Welsh, Extension Horticulture, 225 Horticulture Forestry Building, College Station, TX 77843-2134. Tel: (409)845-7341; Fax: (409)845-8906.

Seattle Water Department, Nota Lucas, Conservation Office, Dexter Horton Building-10th Floor, 710 2nd Ave. Seattle, WA 98104. Tel: (206)684-5855; Fax: (206)684--4631.

Related Articles

"Big Flush, The: Saving Water in the Big Apple" (Anderson)
"Everything I Know about Energy-Efficient Showerheads I Learned in the Field" (Warwick and Hickman)
"Graywater: An Option For Household Water Reuse" (Bennett)
"Low-Flow Showerheads, Family Strife, and Cold Feet" (Meier)
"Pulling Utilities Together: Water-Energy Partnerships" (Jones, Dyer, and Obst)
"Remodeling Bathrooms: Let the Energy Savings Flow" (Johnston)
"The Rise of Water Service Companies" (Berlin)
"Savings and Showers: It's All in the Head" (Proctor, Gavelis, and Miller)
"Shade Trees as a Demand-Side Resource" (McPherson and Simpson)

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