Yardx: Yield and Reliability Demonstrated in Xeriscape - Colorado Water Wise

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Yardx: Yield and Reliability Demonstrated in Xeriscape - Colorado Water Wise

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Yardx: Yield and Reliability Demonstrated in Xeriscape - Colorado Water Wise

  1. 1. Yield and Reliability Demonstrated in Xeriscape Final Report Metro Water Conservation, Incorporated (MWCI) December 2004
  2. 2. Cover: Photo courtesy of David Winger, Denver Water, Denver, Colorado.
  3. 3. YARDXYIELD AND RELIABILITY DEMONSTRATED IN XERISCAPE Final Report Prepared for Bureau of Reclamation And Metro Water Conservation, Incorporated (MWCI) Under Cooperative Agreement 6-FC-60-06670 by Jonnie G. Medina (Bureau of Reclamation) and Julia Gumper (MWCI) December 2004
  4. 4. Citation information: Medina, Jonnie G., and Julia Gumper, 2004: YARDX: Yield And Reliability Demonstrated in Xeriscape: Final Report. Metro Water Conservation, Incorporated, Littleton, CO, 140 p. For copies of the full report, see www.coloradowaterwise.org or contact the Office of Water Conservation at Denver Water.
  5. 5. AbstractMetro Water Conservation, Inc. (MWCI) of Denver, Colorado, in partnership with the Bureau ofReclamation, conducted a water conservation study known as the Yield And Reliability Demonstrated inXeriscape (YARDX) project to estimate the benefits of water-conserving landscaping known as Xeriscape.Benefits to be assessed were seasonal water savings, landscape installation, and annual maintenancecosts. Seven municipalities from Fort Collins, Colorado, to Colorado Springs, Colorado, participated inthe study. The YARDX project is one of five field projects of Reclamation’s National XeriscapeDemonstration Program (NXDP) established to study the benefits of installing Xeriscape under differingclimatic and other potentially impacting conditions.YARDX was conducted from 1997 through 2002. The project included seven field demonstrations, eachwith some differing attributes, including Xeriscape application type (retrofits or new starts), applicationlevel (high or moderate water savings designs), yard size, irrigation method, socio-economic level, andsoil type. In seven demonstrations, control groups of traditional high water use turf were establishedwith similar characteristics to Xeriscapes, except for landscape type. Participants had to installXeriscapes, except at one demonstration. All participants had to maintain them with no major revisionduring the study period. Xeriscape participants were provided a small rebate to join the study, and weregiven education on installing and maintaining Xeriscapes. One demonstration involved comparison ofolder, established Xeriscapes, with comparable control landscapes.Data analysis of historical water use established the need for sample sizes of approximately 30 propertiesstudied over 4 growing seasons, to have at least a 90-percent chance of detecting a 30-percent change inwater use at the 5-percent significance level. The demonstrations yielded high-quality data that generallyenabled the estimation of water savings and annual maintenance costs.Xeriscape installation costs ran a modest $0.90 to $1.45 per square foot, with homeowners in the projectcontributing a substantial amount of labor. Demonstrations obtained water savings from 18 to more than50 percent over control samples. Results indicated that relatively consistently, water savings in the30-percentile range could be obtained for properly designed and maintained Xeriscapes. Annualmaintenance costs ranged from $0.34 to $1.33 per square foot. For cost estimation, homeowner labor wascomputed at $18 per hour. Generally, the maintenance cost of the Xeriscapes sampled, compared to thenon-Xeriscaped properties, was found to be less than controls during the plant establishment years, butsomewhat more during the plant maturation years. This suggests that as Xeriscapes age, they graduallyrequire more maintenance, compared to traditional landscapes.Xeriscape participants overwhelmingly expressed satisfaction with their landscapes and would freelyrecommend this type of landscaping to others. The information gained in the YARDX project shouldprovide an additional alternative in dealing with water conservation needs in the Colorado Front Range.
  6. 6. AcknowledgementsThe nonprofit Metro Water Conservation, Inc. (MWCI), located in Denver and consisting of membersfrom several water utilities from the Colorado Front Range, in partnership with the Bureau ofReclamation, U.S. Department of Interior, funded and conducted the Yield And Reliability Demonstratedin Xeriscape (YARDX) project. The YARDX project is one of five field projects that have contributedinformation to Reclamation’s National Xeriscape Demonstration Program (NXDP).The authors appreciate the MWCI Board of Directors, Mr. Paul Lander of the City of Boulder,Ms. Elizabeth Gardener of Denver Water, Ms. Deb Pilon, Willows Water District, and Ms. Sally Dale(former Board member), Nautilus Resources, for their tireless dedication to the project. For theircontribution of data and support to the YARDX project, we wish to thank Mr. David Winger of theDenver Water, Ms. Jeanie Sims and Ms. Ann Seymour of the City of Colorado Springs Utilities, Ms.Laurie D’Audney of the Fort Collins Water Utility, Mr. John Hendrick and Ms. Diane Schorege ofHighlands Ranch Metropolitan Districts, Mr. Webb Jones of the East Larimer County Water District, Ms.Sue Vest and Mr. Mike DiTullio of the Fort Collins-Loveland Water District, Mr. Chris Koerner and Mr.Ken Peterson of the City of Arvada Utilities Division, Mr. Walt Pettit of the Wheat Ridge Water District,and Ms. Ruth Quade and Mr. Phil Carter of the City of Greeley. Many thanks go to Mr. Steffen Meyer ofReclamation for his tireless assistance to Jon Medina and Julia Gumper in formatting of the report textand to Ms. Elizabeth Gardener for her thorough review of the draft report. Mr. Lonnie Lewis ofReclamation provided editing for the report. The authors appreciate the support provided to YARDX byMs. Avra Morgan, Dr. David Matthews, Mr. Jim Pierce, Mr. Luis Maez, Ms. Christy Bridges, Ms. PaulaSunde, Ms. Julie Swanda (formerly of Reclamation), Mrs. Susan Meyer, and Mr. Tom Phillips all ofReclamation for their support to the YARDX project.
  7. 7. Contents Abstract...................................................................................................................................... iii Acknowledgements..................................................................................................................... v Executive Summary................................................................................................................... xiChapter One—Introduction ......................................................................................................... 1-1 General................................................................................................................................. 1-1 Study Location ................................................................................................................. 1-2 Study Goals...................................................................................................................... 1-2 Previous Studies............................................................................................................... 1-3 Why YARDX in the Front Range.................................................................................... 1-3Chapter Two—Project Design..................................................................................................... 2-1 Introduction.......................................................................................................................... 2-1 Demonstration Characteristics ............................................................................................. 2-2 Study Variables................................................................................................................ 2-2 Sampling Plan .................................................................................................................. 2-3 Sample Size Estimation ................................................................................................... 2-5 Field Data............................................................................................................................. 2-6 Cost Estimation................................................................................................................ 2-6 Xeriscape Installation................................................................................................... 2-6 Maintenance................................................................................................................. 2-6 Annual Surveys................................................................................................................ 2-6 Example of Design........................................................................................................... 2-7Chapter Three—Promotion.......................................................................................................... 3-1 Introduction.......................................................................................................................... 3-1 Promoting Xeriscape Participation ...................................................................................... 3-2 Xeriscape Seminars.............................................................................................................. 3-4 Restricting YARDX Promotion........................................................................................... 3-4 Project Benefits.................................................................................................................... 3-5 Oberservations ..................................................................................................................... 3-6Chapter Four—Installation Cost of Xeriscape............................................................................. 4-1 Introduction.......................................................................................................................... 4-1 Cost Data Quality................................................................................................................. 4-1 Cost Estimation.................................................................................................................... 4-2 Average Installation Costs ............................................................................................... 4-3 Installation Labor ............................................................................................................. 4-5 Costs of Plants and Hardscape......................................................................................... 4-6Chapter Five—Water Use Comparisons...................................................................................... 5-1 Introduction.......................................................................................................................... 5-1 Water Data ........................................................................................................................... 5-2 vii
  8. 8. Water Use Comparisons ...................................................................................................... 5-3 Precipitation ......................................................................................................................... 5-7Chapter Six—Maintenance Costs ................................................................................................ 6-1 Introduction.......................................................................................................................... 6-1 Data Quality ......................................................................................................................... 6-1 Maintenance Cost Calculations............................................................................................ 6-2 Maintenance Cost Results................................................................................................ 6-2 Maintenance Education........................................................................................................ 6-3Chapter Seven—Final Survey...................................................................................................... 7-1 Introduction.......................................................................................................................... 7-1 Specific Survey Questions Analyzed................................................................................... 7-4Chapter Eight—Summary and Conclusions ................................................................................ 8-1 Preface.................................................................................................................................. 8-1 Results.................................................................................................................................. 8-2 Enlisting Participants ....................................................................................................... 8-2 Xeriscape Installation Costs............................................................................................. 8-2 Water Use Results............................................................................................................ 8-2 Maintenance Costs ........................................................................................................... 8-3 Final Survey Results ........................................................................................................ 8-4 Reflections ........................................................................................................................... 8-4 Recommendations................................................................................................................ 8-5 Conclusions.......................................................................................................................... 8-5ReferencesGlossary viii
  9. 9. Appendices (available as a separate file)Appendix A: Xeriscape Participant DropoutsAppendix B: Landscape Installation Audit FormsAppendix C: Landscape Revisit Audit FormsAppendix D: Inflation Rate EstimateAppendix E: Landscape Maintenance FormAppendix F: Final Survey of YARDX ParticipantsAppendix G: Final Survey ResultsAppendix H: Environmental Orientation QueryAppendix I: Sample NewsletterAppendix J: Before and After Photographs TablesTable 2–1: YARDX demonstrations and primary characteristics .............................................. 2-4Table 3–1: Number of participants who signed up, completed or dropped from the YARDX project ................................................................................................ 3-2Table 3–2: Example of Xeriscape signup results from a direct mail campaign ......................... 3-3Table 5–1: Water use comparisons between Xeriscape and traditional landscape samples....... 5-5 ix
  10. 10. FiguresFigure 1-1: Location of cities participating in the YARDX study.............................................. 1-2Figure 2-1: Xeriscape design, Colorado Springs, CO................................................................. 2-7Figure 2-2: Photograph of the Xeriscape 4 years after installation in Colorado Springs ........... 2-8Figure 4-1: Number of new start (NS) and retrofit (RT) Xeriscapes providing installation costs. ................................................................................................................. 4-2Figure 4-2: Average landscape size by demonstration. .............................................................. 4-4Figure 4-3: Average Xeriscape installation cost per square foot by demonstration. .................. 4-4Figure 4-4: Installation hours by homeowner labor only............................................................ 4-6Figure 5-1: Denver water use per unit area (ft2) versus landscape area in Denver..................... 5-3Figure 5-2: Water use for the demonstration sample.................................................................. 5-4Figure 5-3: Demonstration water use savings by Xeriscape group over respective control group. ................................................................................................................ 5-6Figure 5-4: Winter water use. ..................................................................................................... 5-6Figure 5-5: Denver water use in time for April 1999 – January 2002........................................ 5-7Figure 5-6: Colorado Springs water use in time for April 1999 – January 2002........................ 5-7Figure 5-7: Annual precipitation at demonstration projects. ...................................................... 5-8Figure 6-1: Demonstration maintenance cost and number of maintenance reports from all homeowners per each demonstration................................................................ 6-4Figure 7-1: Response rate to Final Survey of all participants per sample group........................ 7-2Figure 7-2: Pro-environmental responses by demonstration. ..................................................... 7-3 x
  11. 11. Executive Summary PURPOSEIn an effort to study the regional effects of water-conserving landscaping called Xeriscape, Metro WaterConservation, Inc. (MWCI) and the Bureau of Reclamation (Reclamation) partnered with nine waterutilities along the Colorado Front Range. The study was entitled Yield And Reliability Demonstrated inXeriscape or YARDX. The YARDX study results were compared to similar studies in four other arid orsemi-arid communities in the western United States. The intent was to provide to utility managers agood basis for future decision making about landscape water efficiency programs.The Colorado project goal was to estimate Xeriscape benefits over a range of landscape and urbanenvironments and within the local climate and weather. Determining benefits involved the study andassessment of landscape water use, installation costs, and annual maintenance expenses. Each of the nineutilities in seven municipalities (Fort Collins, Greeley, Arvada, Wheat Ridge, Denver, Highlands Ranchand Colorado Springs) hosted one or more demonstrations of Xeriscape application. There were 357landscapes for single-family residential homeowner customers in the study. The study design called forassessment of benefits in retrofits (existing landscapes retrofitted with Xeriscape), new starts (newlyconstructed homes), and pre-existing Xeriscapes (previously planted Xeriscape). To assess water savingsand annual maintenance costs, the new Xeriscape sites were compared with nearby traditional landscapesites, either Xeriscape or traditional landscapes. Project participants installed landscapes from 1997 toearly 1999. Operation and monitoring of the project demonstrations occurred over the period 1997through 2002. RESULTSEstablishment of study participant samples proved to be challenging. This was due largely to the cost oflandscapes, tight schedules (people needed more time to install landscapes and deal with associatedexpenses), and the necessity to remain within project guidelines for the duration of the project. Whileinstallation of Xeriscapes by participants was a lengthy process, installation costs appeared relativelymodest, ranging from about $0.90 to $1.45 per square foot (in 1999 dollars). Homeowners contributed allor at least a substantial amount of the labor. Landscapes were completed for as low as $676 and as highas $25,451. Estimated installation labor was an average of 50 to 60 hours per 1000 square feet oflandscape with an automatic irrigation system.Xeriscape annual maintenance costs submitted by homeowners ranged from $0.34 to $1.33 per squarefoot. For cost estimation, homeowner labor was computed at $18 per hour. Generally, maintenance costsfor the Xeriscape sites were less during the plant establishment years, but somewhat more during theplant maturation years, compared to traditional landscapes. This suggests that as Xeriscapes age, theygradually require somewhat more maintenance.YARDX demonstrated that properly planned and installed Xeriscapes save water. The project Xeriscapessaved from 18 to over 50 percent of the water when compared with paired traditional landscape controlgroups. On new properties, YARDX results indicate that water savings in the 30-percentile range canroutinely be achieved, assuming the property owners are committed to maintaining the savings. Newproperty owners obtained their savings with a design scheme of approximately ¼ the area with lowwater use plants, ¼ with moderate water use plants, and up to ½ the area with traditional turf. Higherwater savings could possibly be obtained with a ⅓-⅓-⅓ design scheme. xi
  12. 12. The YARDX water savings from retrofits were slightly less than for new properties (generally 28 to 32percent). Water savings in retrofits appear to vary with the amount of turf that remains in landscapes.Although YARDX retrofit participants were guided toward the ⅓-⅓-⅓ design scheme, the actual watersavings did not reach the anticipated savings of 50 percent.The YARDX project involved the installation and monitoring of landscapes, except for one demonstration(Arvada/Wheat Ridge). In that case, older installed landscapes were only monitored during YARDX.This older landscape study did not yield water savings, and it is not apparent why this occurred. Anumber of differences other than age of the landscape were apparent. This demonstration consisted ofobtaining and comparing the water use of older pre-existing Xeriscapes, with a selected peer controlgroup, as in the other demonstrations. Their watering systems were a mix of manual (also called hosedrag) and automated systems. Over the years, there was likely the usual turnover in ownership, socommitment to maintain the existing Xeriscape design might not have persisted with new owners.YARDX did not provide education about Xeriscape as was accomplished with the other demonstrations.More study of this data set is recommended.The actual data collection for YARDX ended in 2002. A Final Survey was mailed to all projectparticipants to sample their attitudes on their landscapes, installation and annual maintenance costs, andorientation on environmental issues. Overwhelmingly, Xeriscape owners in all demonstrations indicatedthey were very satisfied with their landscapes, and that they would recommend this type of landscapingto others. Interestingly, Xeriscape owners felt they spent less time on maintenance than with previoustraditional landscapes, which did not entirely agree with YARDX maintenance data results.The information gained in the YARDX project should provide Front Range water managers an alternativein dealing with current and future water demand. The general consistency of water savings in YARDXdemonstrations, and the lengthy data collection that occurred, should lend confidence that YARDXresults could be consistently achieved. xii
  13. 13. 1.CHAPTER ONE Introduction GENERAL Population growth on the Colorado Front Range continues at a high level. As a consequence of the semi-arid climate, occasional drought and the continued high growth, Front Range water utilities are accelerating their planning for increasing future water demand. The Bureau of Reclamation (Reclamation) has a responsibility to help improve water resource management and the efficiency of water use in the western United States. Reclamation recognizes that cooperative efforts with partners facing similar challenges can produce solutions more efficiently to benefit all parties. Consequently, Reclamation pursued several cooperative demonstration projects of landscape water conservation, collectively called the National Xeriscape Demonstration Program (NXDP). The NXDP cooperative studies were conducted at locations in the western United States that experience different climates, including the Colorado Front Range centered at Denver, Colorado; Phoenix, Arizona; Austin, Texas; the Las Vegas area of southern Nevada; and Fargo, North Dakota. Xeriscape ™ 1 landscaping is defined as a set of landscaping principles, including low-water-using plants, efficient watering systems, soil amendments, and proper maintenance practices to create an aesthetically pleasing landscape, while maintaining desired attributes, such as reduced water use, recreation, and cooling. In January 1996, Reclamation partnered with a Colorado Front Range nonprofit organization, Metro Water Conservation, Inc. (MWCI), to co- 1 Denver Water, Denver, CO, holds the trademark for Xeriscape. Chapter One 1-1
  14. 14. sponsor the project known as YARDX (YieldAnd Reliability Demonstrated in Xeriscape),aimed at assessing the benefits of waterconserving landscaping. MWCI consists of agroup of Colorado water supply agencies andinterested stakeholders cooperating to aidplanning for future water demand and supply,and to promote water conservation programs.Reclamation, MWCI, and nine water utilities inthe Colorado Front Range comprised the groupparticipating in and sponsoring the YARDXproject.STUDY LOCATIONThe YARDX project became a 5-yeardemonstration and evaluation study based onXeriscapes installed in nonrental, single-familyhomes along the Colorado Front Range. Thearea targeted in the Colorado Front Range is themost heavily populated in the state. The studyincludes landscapes in neighborhoods of FortCollins and Greeley in the north, Denver andseveral suburbs in the middle Front Rangecorridor, and Colorado Springs in the south. Figure 1-1: Location of citiesFigure 1-1 presents the study locations. This participating in the YARDX study.region is considered high plains with a semi-arid climate that receives on average 15 inches ofyearly rainfall in Fort Collins and Denver, and Specifically, the primary study goals of YARDX17.5 inches in Colorado Springs were:(http://www.weatherbase.com). • Conduct consistent investigations atSpecifically, the nine utilities and 357 of their multiple sites in different geographicsingle-family customers that elected to join the and municipal settings.YARDX project are the Fort Collins Utilities,East Larimer County Water District (Fort • Collect data that are uniform in contentCollins), Fort Collins-Loveland Water District, and method.City of Greeley, City of Arvada, Wheat Ridge • Quantify the range of water savingsWater District, Denver Water, Highlands Ranch annually and seasonally when XeriscapeMetropolitan Districts with Centennial Water is properly installed and maintained.District, and Colorado Springs Utilities. • Determine the reliability of XeriscapeSTUDY GOALS water savings (Do water consumption patterns change with the age of theThe YARDX study goals were to develop data landscape or varying human factors?).and provide evaluation and estimates on thewater savings, installation, and annual • Calculate the cost of installing Xeriscapemaintenance costs in implementing Xeriscape. landscapes for new construction and forThe project was to assess the reliability of retrofits to existing traditionallandscape water conservation from the landscapes (mostly high-water turfapplication of Xeriscape landscaping. landscapes).1-2 Introduction
  15. 15. • Analyze the cost of maintaining evaluations dealt with water use in single-family Xeriscape landscapes for new residences, as did YARDX. construction, for retrofits to formerly traditional landscapes, and for pre- WHY YARDX IN THE FRONT RANGE existing (installed prior to YARDX) Xeriscapes compared to pre-existing Motivation for incorporating the Colorado Front traditional Kentucky bluegrass Range in the NXDP national study included: landscapes. (1) the high-growth characteristic of the area, (2) concerns over prolonged drought in the state, • Identify what marketing strategies (3) urban landscapes accounting for affected the implementation of approximately 50 percent or more of the water Xeriscape in this study. used by residences in this region (Winger), and (4) the citizenry’s familiarity with Xeriscape.PREVIOUS STUDIES As people continue to select Colorado for its moderate climate, variety of outdoor recreation,Some results from the other NXDP field studies jobs availability, and retirement appeal, waterare now available. The Phoenix project demand will increase. Front Range corridor(Stinnett) obtained water savings of 53 percent growth is exemplified by “six counties in theover control properties with traditional state [making] the census’ list of the 100 fastest-landscaping. This project was similar to a growing counties in the nation” and HighlandsYARDX pre-existing Xeriscape landscape study Ranch in Douglas County, a southern suburb ofconducted in Arvada/ Wheat Ridge Denver, Colorado, and part of the YARDXneighborhoods, except for lack of an observation study, “was the third-fastest-growing county inperiod. The Phoenix study involved selecting, the nation from 2000 to 2003 “ (Siebert,acquiring, and evaluating landscape historical Sinisi, B1).water use data. The U.S. Housing Markets, a research firm,The Southern Nevada project (Sovocool and announced in 1997 that the FortRosales) obtained water savings of 39 percent Collins/Loveland area (part of the YARDX(summer) over control properties. Xeriscape study) ranked number 9 in the country inmaintenance was estimated to be about ⅓ less residential construction, with the Greeley areathan for control properties. (also part of YARDX) holding the number 18 spot in the United States (Cornelius C1+). ThisThe Austin Xeriscape project (Gregg, 1994) Front Range metropolis, from Weld County inobtained water savings of 31 percent during the north to Pueblo County in the south,summer months. Nelson (1994), in preliminary includes about 3,733,308 residents (Romine).results of the North Marin Study, obtained a 25-percent water savings from Xeriscape. Testa The high growth and difficulty of executing newand Newton (1993) obtained a 33 percent water traditional water projects has motivated watersavings in a Mesa, Arizona, study of Xeriscape. utilities to consider water conservation alternatives to water supply developmentXeriscape participants in all projects of the options, in part, because of the economic andNXDP have overwhelmingly expressed environmental concerns associated withsatisfaction with their landscapes and indicated traditional water projects. Landscapethey would freely recommend this type of irrigation’s water use near 50 percent oflandscaping to others. residential use is an ideal target for waterThe above studies have provided evidence conservation, and offers a potential source forsuggesting that Xeriscaping can reduce dealing with a major challenge of future Frontlandscape water usage by 20 to 50 percent Range growth.during peak irrigation months, as compared to Front Range landscapes with predominantlytraditional turf landscapes. Those water-use thirsty Kentucky bluegrass typically need nearly 30 inches additional water over average rainfall Chapter One 1-3
  16. 16. (Winger) to maintain their health. As suggested and mulched areas without plantings. Thisin the previous studies discussed above, lower landscaping approach is particularly beingwater demand plantings and more efficient utilized in moderate and higher pricedirrigation methods could potentially decrease properties. Positive results from YARDX andoutdoor watering by 30 to 50 percent, or about readily available educational materials from10 inches less irrigation. Noticeable water water utilities (for example) could furthersavings are obtained when viewed over the promote the installation of water conservingmany landscapes of the Front Range. plantings.The extreme Front Range drought of 2002 Following in this report are descriptions of the(exceeding 100-year records) and the continuing YARDX project and the results obtained.dry years have contributed to increasing interest Chapter Two discusses the project design,in water conservation approaches. The 2002 Chapter Three covers the promotion efforts todrought persuaded utilities to enact watering recruit homeowners to join YARDX and install arestrictions. These restrictions apparently Xeriscape. A summary of the Xeriscapeimpacted the 2002 water savings by YARDX installation costs is given in Chapter Four.Xeriscapes in Colorado Springs (discussed in Chapter Five presents water use results, andWater Use Results). Drought remains an ongoing Chapter Six covers landscape maintenance costs.concern in Colorado. Chapter Seven presents the YARDX participants’ responses to a Final Survey thatXeriscapes are a familiar sight in Colorado Front included questions on satisfaction with theirRange municipalities, rendering the area a likely landscape and query for pro-environmentalcandidate for Xeriscape research. In new tendencies that may have influenced their waterneighborhoods, there are indications of use. Finally, Chapter Eight presents a summaryincreasing use of lower water demand plantings and conclusion of primary results.1-4 Introduction
  17. 17. 2.CHAPTER TWO Project Design INTRODUCTION A proper evaluation plan and data sampling design was required to accomplish the goals established for YARDX. However, design features would need to function within demonstration logistics. The desired sampling scheme was random allocation of the treatment (Xeriscape) and control (traditional landscape) to lessen possible bias. From a large pool of willing participants, homeowners would be assigned to treatment and control groups at random. Treatment participants would install Xeriscapes and control participants would install traditional landscapes. It was also determined to sample only owner-occupied, single-family properties to reduce noise that may occur from rentals or multiple-family housing. To encourage participation, a rebate was established of $300 to new starts (newly constructed homes), and $600 to retrofits (Xeriscaping a portion of an established high-water use landscape). Also, Xeriscape participants would be provided 2.5 hours of professional landscape design assistance, educational seminars on Xeriscaping, and one-on- one consultation upon request during the study period. In the initial stages of the project, it became apparent that establishing a treatment group with random selection would not be possible, despite the benefits provided by YARDX. There was inadequate participation to install Xeriscapes. The primary barrier appeared to be Xeriscape installation cost and time, though other concerns voiced included conforming to the rigor of participation (e.g., reporting requirements) and structured Xeriscape design features and irrigation type selected for particular demonstrations. Elimination of random allocation to the treatment group forced development of a new Xeriscape Chapter Two 2-1
  18. 18. sampling plan, possibly introducing more data 2. Xeriscape application type (retrofit, newnoise. start or pre-existing)That nine utilities expressed interest in joining 3. Xeriscape application level (landscapeYARDX also impacted the study design. Large designed for 30-40 percent orparticipation presented an opportunity to develop 60-70 percent water savings)seven demonstrations, each with at least one 4. Yard sizeunique variable factor setting (such as large yardor sandy soil). 5. Irrigation method (manual hose drag or automatic sprinkling system)The project covered approximately 6 years of 6. Family income level (home values wereinformation gathering, as a consequence of the used to approximate income levels)landscape enlisting and installation processbecoming rather time consuming. The YARDX 7. Soil type (loam, sand, or clay)project began enlisting properties in 1997. 8. PrecipitationXeriscapes were installed from 1997 through thefirst half of 1999. Field data collection continued The first variable, water use, is the key responseuntil the end of 2002. Data responses from (dependent) variable of the study. The other listedparticipants continued well into 2003. variables, operating in combination, are considered to substantially impact water use.DEMONSTRATION YARDX collected data on some secondary variables, including exposure of a landscape toCHARACTERISTICS wind (a categorical variable as defined byConsideration was given to the various variable YARDX), degree of shadiness (more important infactor influences (Gregg, et al.) on study sample retrofits that had pre-existing plants remainingestablishment, including project duration and and providing shade), and area with 15-degreeavailable funding. Table 2-1 lists the YARDX slope or greater. A variable not listed above thatseven demonstrations along with their primary certainly impacts water use, but is difficult toinfluence factor and logistic characteristics. In assess, is landscape maintenance. YARDXgeneral, a mixture of three retrofit, three new collected related information via an assignment ofstarts and one pre-existing (Xeriscape landscapes a landscape or turf health score (see appendix C).installed prior to YARDX, by the spring of 1996) While the health score assignment was subjectivedemonstrations was developed for YARDX. (by the person conducting the field audit), thereMarketing failed to convince more homeowners to may be some useful maintenance level assessmentparticipate in additional demonstrations, except in the scores.possibly for additional high-priced properties thatmay have joined if pursued. The table shows the Table 2-1 shows the various influences of factordemonstration in Greeley as a mix of retrofits and settings by demonstration. Because landscapenew starts. This occurred because few people water use is the end result of a number ofjoined the project. operating and interacting factors such as weather and climate, soil type, yard size, and homeDemonstrations were designed to address occupant attitude, individual neighborhoods ofvariables that appear to impact water use. differing demographics may yield different waterPrevious studies (Gregg, et al.) have identified use savings.variables that are correlated with water use.Accordingly, the YARDX field demonstrations Xeriscape application type refers to a Xeriscapewere structured to yield data on eight seemingly new start, retrofit, or a pre-existing type.correlated variables, including the primary Xeriscape application level relates to the presumedresponse variable, water use. water savings level of the Xeriscape design, based on the area ratio landscaped in high-, moderate-,STUDY VARIABLES or low-water plants (see Glossary) plus the area 1. Water use (primary response variable) amount of hardscape. For YARDX, two2-2 Project Design
  19. 19. application levels were selected: 30-40 percent whatever type of irrigation system had beenwater savings design (used in the new start installed, and thus a mixture occurred in thisdemonstrations) and the higher water savings of group.60-70 percent (used in the retrofit demonstrations).The 30-40-percent design consisted of ¼-¼-½ area Home value was used as a surrogate forratio of low, moderate, and high water use. The attitudinal variables of family income levels that60-70-percent design used corresponding area some previous studies (Gregg, et al.) suggestedratios of ⅓-⅓-⅓. The pre-existing landscapes were could affect household water use. The home valuetaken “as is.” Consequently, a combination of representation varied by region. One value thatdifferent potential water savings landscape plans may seem low in one locale could reflect a high-existed in these yards. priced home in another city. A relative comparison system on a local basis was used.The water savings estimation levels (Xeriscape Three general classes of home values are identifiedapplication levels) could possibly be achieved on Table 2-1: low, medium, and high.under proper designing and installing, wateringand performing general maintenance (such as The soil types also fell into three main groups:thinning plants). Landscape designs were loam, clay, and sand. In some demonstrations,structured to specify certain water-hardy plants there were some properties with mixes, butand grasses, density level of installation, generally there was a predominant soil type.proportion of turf to nonturf area, and landscape Lastly, three groupings of relative precipitationpreparations that included soil preparation, were prevalent during the growing season ofmulches, and hardscape. April through October in YARDX demonstrations.The variable yard sizes were categorized into The relative code of ”low“ indicated aboutsmall, medium, and large. The classification was 8 inches or less, “moderate” reflected more thanrelative to each city, so that category size cut-offs, 8 and up to about 11 inches, and “wet” indicatedfrom city to city, varied minor amounts. Thus, 12.5 inches or more of rainfall.large yards in Fort Collins tended to be larger thanlarge yards in the Denver demonstration area. SAMPLING PLANThe study in Fort Collins was structured to Because random allocation of the treatment wasinclude larger properties and more affluent not possible, a new sampling plan was needed, atowners. Table 2-1 presents the yard size cut-offs. least for establishing the Xeriscape sample. ForApproximately, the three size categories that each demonstration, the goal was still to have thedescribed one-half of the “landscapable area” treatment and control group properties as similar(square footage to be formally landscaped) were: as possible, except for random assignment of thelow-sized yards up to about 2750 square feet, treatment. After some consideration, the samplingmedium sizes from approximately 1000 to 4000 plan was developed that involved:square feet, and large sizes with over 2500 squarefeet. The Xeriscape landscape had to encompass • Only certain households were willing to50 percent or more of the landscapable square participate in the project. The greatestfootage. This area did not include dryland area difficulty in obtaining participants was in(natural vegetation surviving solely on rainfall). the Xeriscape group.Only one YARDX property involved dryland area. • Willing Xeriscape participants wereOnly two types of irrigation systems were studied surveyed to conform to settings of thein the project: automatic sprinklers on a clock and relevant demonstration. Participants (andtimer that would start and stop the watering as properties) that satisfied theirprogrammed, and hose dragging. In each demonstration settings were invited todemonstration, all participants (both treatments join the study.and controls) had the same type of irrigationsystem with the exception of the pre-existingdemonstration. In this case, YARDX accepted Chapter Two 2-3
  20. 20. 2-4 Table 2–1: YARDX demonstrations and primary characteristics. Xeriscape Periods ofProject Design Demo Level ½ Yard Water Data Demo Type 1 (%)2 Soil Rainfall 3 Size (ft2) Home Value Irrigation Analyzed Arvada/ PX Any 4 Clay 8" 1000-4000 $150-275,000 As Is 9/99 -- 12/02 Wheat Ridge (Moderate) (Medium) (Medium) Colorado RT 60-70 Clay 12.5" 1000-3750 $150-200,000 Auto 2/99 -- 12/02 Springs (Wet) (Medium) (Medium) Colorado NS 30-40 Sand / 12.5" 1000-3750 $150-200,000 Auto 2/99 -- 12/02 Springs sandy loam (Wet) (Medium) (Medium) Denver RT 60-70 Clay 9" up to 2750 up to $200,000 Manual 5/98 -- 12/02 (Moderate) (Low) (Low) Ft. Collins / NS 30-40 Clay 9" >2500 >$175,000 Auto 9/98 -- 12/02 Loveland (Moderate) (High) (High) Greeley RT & 60-70 Loam 8" 1000-3750 $80-200,000 Auto 2/98 -- 12/02 NS (Low) (Medium) (Medium) Highlands NS 30-40 Clay / 11" 1000-4000 $150-250,000 Auto w/ 2/98 -- 12/02 Ranch clay-sand (Wet) (Medium) (Medium) submeter 1 NS= New Start; RT= Retrofit; PX=Pre-existing 2 Xeriscape application level was designed for a 30-40% or 60-70% water savings over traditional landscapes. 3 May to September average rainfall 4 The Arvada/Wheat Ridge demonstration was not a YARDX-designed project, and Xeriscape application levels were not specified.
  21. 21. • With knowledge of Xeriscape toward pro-environmental orientation over participant characteristics, a pool of control groups. However, this result may have properties with traditional landscapes occurred as a result of several circumstances. It was surveyed for matching the is not clear that pro-environmentalism always treatment characteristics. A random leads to higher water conservation. sample was selected of the acceptable control pool, in excess of treatment SAMPLE SIZE ESTIMATION numbers. Sample sizes must be large enough to enable the • Those randomly selected were contacted detection of a treatment effect (Xeriscaping in for joining the control group of the this study) on water savings anticipated from particular demonstration. Not all Xeriscape application. The natural “noise” contacted agreed to join the study. levels of the local water-use data must be Upon enlisting the desired number of assessed to estimate sample sizes. Data noise control participants, the contacting sources can occur from influential elements ceased. changing with time (such as effects of weather) and influences varying across households. Real • Information conveyed to control water-use historical data offer an opportunity to participants consisted of only stating estimate sample size requirements. that they would belong to a local landscape water-use study of traditional Several years of water-use data were obtained landscapes (to avoid potential influence from the city of Boulder, Colorado, for some on water use). No education on 26,000 homes. The project team agreed that the landscaping was provided to control Boulder data were well representative of wide participants by YARDX. socio-economic, educational, and other water- use-impacting variables. Given this assumption,The restricted population of willing Xeriscape the Boulder water data would be a suitableparticipants could lead to some bias in the candidate for sample size estimation for YARDXsamples obtained. The project also used a rebate demonstrations.to aid in obtaining adequate numbers ofparticipants, which could introduce some bias. Computer software was developed that utilizedThe rebate undoubtedly motivated some a resampling technique similar to bootstrapparticipation (see Chapter Seven, Final Survey). (Manly) that uses random selection of samples,Finally, new home construction leads to the which can be compared. This technique wasneed for new landscapes (neighborhood used to study the detection of different watercovenants usually require homeowners to install amount savings in different sample sizes froma landscape). The type and amount of bias samples without water savings. For example, aresulting from these initial conditions was 30-percent increase in water use was applied todifficult to foresee. In particular, the rebate each of 100 randomly selected samples ofcould lead to specific types of water users. residential water use and compared with 100However, the project team realized that some unaltered samples, using a nonparametric test atparticipants may simply want to conserve water. the 5-percent significance level. By studying theOthers seemed attracted to the aesthetics of proportion of comparisons over and under theXeriscape. 5-percent significance level, an estimate of probability of detecting the inserted waterEfforts made to investigate bias consisted of amount change was obtained.studying responses in a survey administered atthe end of the project by YARDX (see Chapter Results of applying different water amountSeven, Final Survey). Specific questions on the changes in different sample sizes indicated thatsurvey suggested the environmental inclination to achieve the 90-percent detection level, waterby participants and the primary motivation for use from about 30 homes for approximately 25joining the study. Results in Chapter Seven growing season months would be required tosuggest some bias of Xeriscape participants detect a 30-percent water savings. This meant Chapter Two 2-5
  22. 22. that water data should be collected from about season water use, with the exception of the30 homes per sample for four growing seasons Highlands Ranch demonstration, had to bein the YARDX demonstrations. The growing derived from readings from the utility-providedseason selected was April through October. home water meter. In the case of HighlandsThis sample size included about 10 percent Ranch, an additional meter was installed tooverage for participant dropout during the measure only the landscape water use. Thesestudy. The sample estimate would data were available for the last two growingaccommodate typical data noise caused by seasons only (2001 – 2002).varying climate effects, property characteristics,irrigation systems and management, and COST ESTIMATIONhomeowners’ varying behavior. Xeriscape InstallationFIELD DATA One of the primary goals of YARDX was toFor their customers in the YARDX study, the estimate the cost of installation of Xeriscapes.participating utilities routinely collected Data were obtained from six demonstrations.monthly or bimonthly water-use information. The seventh demonstration, the Wheat Ridge /This information was provided to the YARDX Arvada study, did not involve the installation ofproject for analysis over the course of the study. landscapes, but rather the study of existingTable 2.1 shows the periods of water data for Xeriscapes and traditional landscapes. Seeeach utility. The water data required substantial Chapter Four for a detailed discussion ofmanipulation for the final tabulation. The final installation costs.tabulation consisted of calendar monthly totals(obtained from reporting period average daily Maintenanceusage) per participating property. The Annually, both the treatments and controlsestimated monthly totals became the water-use received a maintenance log to record their timebasic database for treatment and control sample and expenses on their landscapes. Segregatedcomparisons. by major landscape area (e.g., turf, groundcover plants and perennials, irrigation, etc.) and byGenerally, water-use data were available from three seasons (spring, summer/fall, and winter),mid-1998 or early 1999 through 2002. Water-use these data were tabulated annually from 1997data files were constructed with complete through 2002. A discussion of maintenancerecords through 2002 for all participants. A few costs can be found in Chapter Six, Maintenanceproperties underwent major landscape revisions Costs, and the form can be found in Appendix E.no longer in character with the particulardemonstrations. These records were adjusted In addition to studying the maintenance costs,for a partial study time period and included in the effect of providing landscape maintenancethe analysis. education was also considered. Xeriscape maintenance training was provided to the newTo estimate outdoor use, winter use was start and retrofit treatment groups but not to thesubtracted from summer meter readings. pre-existing sample. By isolating the pre-Winter use was estimated by averaging water existing group, the effects of maintenanceuse for January, February, November, and training could be better observed between theDecember. These were considered the core “trained” and “untrained” groups.winter months most likely to include little or nooutdoor use. The project team decided thatusing the average of “encircling” months best ANNUAL SURVEYSrepresented indoor use. For winter comparisons Also annually (from 1997 through 2002), bothbetween samples, the water use in March was the treatments and controls received a survey.included with the above 4 months. The purpose of this survey was to identify the age of the property and indoor water-usageThe growing season months were designated as factors such as the number of adults andApril through October. Estimation of growing2-6 Project Design
  23. 23. children, the number of low-flow toilets and EXAMPLE OF DESIGNshowers, etc. At the conclusion of the study in2002, the survey was expanded to determine Figure 2-1 presents a sample plan designed for aattitudes toward their landscapes and study participant. Figure 2-2 depicts theenvironment. The results of this survey can be completed Xeriscape 4 years after installation.found in Chapter Seven, Final Survey. Other homeowners’ landscape photographs, before and after installation, can be found in Appendix J. Figure 2-1: Xeriscape design, Colorado Springs, CO. Design created by Joelle Dunaetz, Designs by Dunaetz. Chapter Two 2-7
  24. 24. Figure 2-2: Photograph of the Xeriscape 4 years after installation in Colorado Springs. Photo courtesy of participant.2-8 Project Design
  25. 25. 3.CHAPTER THREE Promotion INTRODUCTION The YARDX project was designed to study owner-occupied, single-family residential homes. Project participants would be homeowners willing to install a new Xeriscape landscape (treatment) or maintain a traditional landscape (control) throughout the study. YARDX offered a rebate to treatments to participate in the study (except for the pre- existing demonstration). Most of the cost of installing Xeriscape would be borne by those willing to participate. In each demonstration, approximately 45 to 55 homeowners were targeted for each of the treatment and control groups. The team planned to enlist about 40 participants, nearly 20-percent over subscription, to deal with anticipated attrition. The sample size estimation of Chapter Two indicated the need for about 30 participants per sample group completing the study. Accordingly, five of the seven demonstrations achieved the desired number of signups at the onset. Table 3-1 indicates a total of 294 Xeriscape participants signed up and paid a $100 commitment check (where required). Participants were given time schedules for completing their Xeriscapes. A total of 170 Xeriscape participants of the original 294 that initially joined YARDX (58 percent of 294) completed the study. Thus, 124 Xeriscape participants failed to complete YARDX. Each demonstration was designed with pre-specified criteria of participation. Failure was caused by violation of criteria, such as failing to install a required automatic watering system. Even with high attrition, all but the Greeley demonstration had Chapter Three 3-1
  26. 26. Table 3–1: Number of participants who signed up, completed or dropped from the YARDX project. No. that Completed Project to No. of the End 1 (% of Signups) No. of Treatments Treatment Dropped from ProjectDemonstration Signups Treatments Controls (% of Signups)Arvada/Wheat Ridge 30 26 (87%) 28 4 (13%)(PX)Colorado Springs (NS) 52 27 (52%) 37 25 (48%)Colorado Springs (RT) 64 27 (42%) 32 37 (58%)Denver (RT) 63 34 (54%) 31 29 (46%)Fort Collins (NS) 46 34 (74%) 38 12 (26%)Greeley (NS & RT) 13 6 (46%) 4 7 (54%)Highland Ranch (NS) 26 16 (62%) 17 10 (38%)Total 294 170 (58%) 187 124 (42%)Legend: RT = Retrofit Xeriscape NS = New Start Xeriscape PX = Pre-existing Xeriscape 1 The project was able to use only partial data on 12 treatments and 8 controls due to changes to their landscapes late in the study.adequate participation for conducting data used at times. Included in the mailing was aanalysis. colored flyer with Xeriscape landscapes, a brief letter, and an application form. When aAppendix A presents drop-out numbers with homeowner called or returned an applicationbreakdown by city and reason for leaving the form, YARDX responded with an additionalproject. letter covering more details about the project, including costs of installing a Xeriscape.PROMOTING XERISCAPE Applicants were then asked to confirm theirPARTICIPATION interest with a mail-back form. Lastly, the project team prequalified the interestedThe YARDX Project used several different homeowners with a drive-by audit checking foravenues to elicit homeowner participation in the approximate home value and age, irrigationXeriscape group. The primary approach was a system, yard size, soil type, etc., for matchingdirect mailing campaign to preselected the demonstration’s study settings.neighborhoods that fit the criteria for thedemonstration (home value, soil type, etc.), and At each level of scrutiny, homeowner responseto new water tap permittees (for homes recently levels dropped. Participation confirmationbuilt for the new start demonstrations). Over requests were below expectations.19,600 letters were mailed to prospective Approximately 234 homeowners (24%) of theparticipants by 9 utilities on utility letterhead. original 965 who expressed interest in installing a Xeriscape responded favorably to ourTable 3-2 shows homeowner approximate confirmation request. Of the original 19,600response to the Xeriscape direct mail campaign. homeowners that were contacted, 1.2 percentAbout 5 percent or 965 prospective participants replied that they wanted to proceed withresponded with interest. Second requests were3-2 Promotion
  27. 27. Table 3–2: Example of Xeriscape signup results from a direct mail campaign. Signups No. of No. of Qualified No. of Applications Homes Invita- Received (% of % of % of % of tions (% of Invitations / Invita- Appli- Quali- Demonstration Mailed Invitations) % of Apps) No. tions cations fied Arvada (PX) 664 54 (8%) 24 (4%) / (44%) 20 3 37 83 Boulder (NS) 143 14 (10%) cancelled cancelled demonstration demonstration Colorado Springs 7,305 360 (5%) 280 (4%) / (78%) 81 1 23 29 (NS & RT) Denver (NS) 586 23 (4%) cancelled 2 0.3 9 — demonstration Denver (RT) 1,524 246 (16%) not available 63 4 26 — Ft. Collins (NS): Ft. Collins Utility 355 31 (9%) 28 (8%) (90%) 13 4 42 46 Ft. Collins- 160 27 (17%) not available 10 6 37 — Loveland East Larimer 38 16 (42%) not available 6 16 38 — County Ft. Collins Total 553 74 (13%) not available 29 5 39 — Greeley 7,058 194 (3%) 135 (2%) / (70%) 13 0.2 7 10 (NS & RT) Highlands Ranch 544 not available not available 26 5 — — (NS) Subtotal 18,377 965 (5%) -- 234 1 24 — Various 1,223 not available not available not available Grand Totals 19,600 965 (5%)1 -- 234 1 24 — Legend: RT =Retrofit Xeriscape NS =New Start Xeriscape PX =Pre-existing Xeriscape 1 Calculated without Highlands Ranch resultsinstalling a Xeriscape. These results forced a educate the citizenry about the overallprolonged marketing effort. benefits and aesthetics of Xeriscape, but did not specify information on YARDX.Besides mailing invitations to prospectiveparticipants, several other marketing campaigns • The government channel on cable TVwere added to help enhance YARDX credibility promoted the project in Coloradoand circulate availability more widely. Springs and Greeley.Additional marketing included: • Newsletter articles were published • Approximately 19 newspaper articles and/or presentations made to such highlighting the project and its benefits organizations as the Home Builders were circulated in various papers and Association, real estate agent groups, cities. homeowner associations, environmental groups, garden centers, Colorado State • About seven paid newspaper ads were University Extension, the Horticulture printed in local newspapers. Arts Society, the Associated Landscape Contractors of Colorado, and the • Denver Water sponsored several TV Nurserymen’s Association. These news bites about Xeriscaping on a local groups were in contact with the public TV news station. This publicity helped Chapter Three 3-3
  28. 28. and likely enhanced promotion of demonstration. The control sign-up process YARDX. started in 1998 and continued into 1999. • Letters were sent regarding YARDX to XERISCAPE SEMINARS more than 100 builders and Home Builder Association members in the Homeowners who confirmed their interest to Colorado Front Range. In addition, participate in YARDX were subsequently YARDX representatives visited or called invited to a 2½-hour Xeriscape seminar in their several homebuilder sales offices to neighborhoods. At these seminars, members of utilize their contacts with the public. the project team discussed the requirements of These efforts produced varying degrees the project, the benefits, preparation for a of support for YARDX. private design session with a landscape architect/designer, the seven principles of • Flyers were deposited at single-family Xeriscape, and the procedures and costs residential homes, at libraries, and at involved with installing a landscape. At the homeowner associations in Fort Collins, seminar conclusion, the team signed up Greeley, and Highlands Ranch. The participants, which required a $100 commitment Colorado Springs Xeriscape check. These monies helped to subsidize the Demonstration Gardens passed out homeowners’ private design sessions. In some YARDX flyers to their visitors. cases, YARDX representatives met with homeowners who were unable to attend • Some utilities mailed inserts with water scheduled seminars. bills. • The Fort Collins Utility taped a video of RESTRICTING YARDX the YARDX introductory Xeriscape PROMOTION seminar for distribution to interested homeowners. YARDX established standards and related expectations of treatment and control groups. • For locating pre-existing Xeriscapes in These demands may have contributed to the Arvada, a mailing was conducted to slow signup rate. However, obtaining high participants in the city’s previous quality data demanded rigor in the conduct of Xeriscape rebate program. Also, the project. Arvada and Wheat Ridge representatives assisted in identifying Standards required of new start and retrofit areas of existing Xeriscapes in their Xeriscapes were similar. The pre-existing neighborhoods. Xeriscapes had less demands, as those Xeriscapes were already established and theThe Xeriscape marketing effort started late in interest was to evaluate the water savings ofthe summer of 1996 and continued through the older Xeriscapes. The following lists somewinter of 1998, exceeding the original time landscape requirements established for YARDX:schedule and plans. YARDX spent at least anadditional year on marketing due to initial low • The retrofit and new start homeownerssign-up rates. had to commit with a $100 nonrefundable check, which would beMass marketing techniques were not used to returned to them through projectelicit homeowners for the control role. Chapter benefits. This fee was enacted to helpTwo presents procedures for selecting control determine participants likely toproperties. Promotion consisted of personal complete their installations.door-to-door contact on randomly selectedproperties that were determined to closely • Retrofit and new start homeowners alsomatch treatment properties of the had to have their landscape plans approved and installed by June 1, 1999. The plan had to encompass over3-4 Promotion
  29. 29. 50 percent of their landscape. For new 100 percent of those completing their starts, they could not have an existing installations received the maximum landscape older than 6 months in at rebate allowed. least 50 percent of the yard. Conversely, the retrofit demonstrations had to have • Participate in YARDX-exclusive an existing landscape. Both groups had discounts negotiated with 25 vendors in to track their installation work time and 5 cities throughout the study region. expenses and submit copies of all These discounts averaged 10 to invoices to YARDX. 20 percent and included nurseries and garden centers, irrigation • Annually, the homeowners were to suppliers/contractors, soil amendment report landscape maintenance including providers, hardware stores, and tracking their time and expenses, hardscape suppliers. completing an annual survey, and providing YARDX with photos of their • Receive a 2½-hour private session with yard. The project supplied a a landscape architect or designer paid maintenance tracking form. The pre- for by the YARDX Project. Participants existing Xeriscapes were not required to were given a simplistic homework submit photos. assignment to complete before their design session: photograph their yard, • Homeowners were asked not to complete a questionnaire about their significantly alter their landscape desires, and draw a schematic of their during the study (concluding property with measurements. December 31, 2002) and to allow project staff to occasionally view the progress of • The YARDX Project provided one free the Xeriscape. maintenance seminar in four demonstration cities (Greeley, Fort • Participants had to own their home (no Collins, Denver, and Colorado Springs). renters); not be an employee of their Additionally, an annual newsletter with utility, Metro Water Conservation, Inc., maintenance tips was mailed to all the or Reclamation; and have no expectation Xeriscape participants except for the of moving in the next 3 to 5 years. pre-existing group in Arvada and Wheat Ridge. The plan was to observe • For the Highlands Ranch demonstration what the pre-existing demonstration only, Xeriscape participants were would do without any formal required to install a submeter on their maintenance education from the project. irrigation line to measure outdoor watering. The submeter was provided • At the conclusion of the study, the by the utility, but the homeowners were YARDX project team is to provide each responsible for its installation. homeowner with a personalized analysis of their water use, installationPROJECT BENEFITS costs, and maintenance expenses, comparing their results to those of otherThe total benefit package offered to the project participants.treatment group encompassed: • Some general benefits include increased • Receive a rebate of $0.45/ft2, up to a home value through an attractive maximum of $300 for new starts and landscape, and reduced water bills by $600 for retrofits, depending on the size saving water. Homeowners would be of the Xeriscape installed. No rebate helping the environment by creating was disbursed to pre-existing Xeriscape microclimates and reducing energy homes, since they had already needs, reducing wastewater through completed their installations. Almost reduced water applied to landscapes, Chapter Three 3-5
  30. 30. maintaining higher water quality return • The utilities with dedicated staff on the flows (assumed less pesticides and Project had better signup results. fertilizers), and assisting utilities to better deal with future water demand • Signups for the retrofit treatment group planning and demands. Water progressed better than for the new starts conservation can provide immediate (about 13 percent better) despite benefits without requiring marketing for only two retrofit environmentally sensitive water demonstrations compared to three new projects. start groups. The smaller population of new homeowners (compared to theThe promotion campaign advertised project number of homeowners with existingbenefits to entice homeowners to join YARDX. landscapes) indicated they wereThe value of the provided landscape design, overburdened with new home expensesinstallation discounts, and project rebate were and tasks and thus were reluctant toassessed as high as $1000 for the higher rebated commit to a new type of landscape.properties. Often their builders provided Kentucky bluegrass in parts of their yard,The main benefits for the control group were the diminishing the need for a completepersonalized analysis of their water use and landscape. Additionally, manymaintenance expenses, and the comparison to homeowners had small children whoother participants in the project. They also needed grassy areas for play and chosegained the satisfaction that they were helping mostly turf landscapes.their utility better determine the water use oftraditional landscapes. • After newspaper articles were published about YARDX, the utilities wereTwo pre-existing Xeriscape demonstrations inundated with inquiries (Denver aboutwere dropped: Boulder and Colorado Springs. 150 phone calls and Colorado SpringsBoulder switched from being a new start about 1400). Most of these callers lackeddemonstration to a pre-existing demonstration. sufficient interest to proceed.They received a poor response from letters sentto homeowners who had previously been • The Fargo, North Dakota, Xeriscapeidentified as having a Xeriscape landscape. study also experienced new start signupSince Colorado Springs was already hosting two rates less than initially anticipated,demonstrations, a retrofit and new start, they despite using a higher rebate amount ofdecided not to pursue a pre-existing $1200, or four times the YARDX newdemonstration as well. start rebate of $300 and twice the retrofit rebate of $600. However, the FargoOBSERVATIONS rebate did contribute to an increased interest in the retrofit demonstration.During the promotion campaign, some successand lack thereof became apparent. Thefollowing lists some observations on theseissues:3-6 Promotion
  31. 31. 4.CHAPTER FOUR Installation Cost of Xeriscape INTRODUCTION Estimation of the cost of installing Xeriscape was one of three major goals of the YARDX study. The cost of Xeriscape will likely impact its level of implementation. Participants in Xeriscape samples of six demonstrations (excluding the pre-existing group) were asked to submit receipts of costs of materials and labor pertaining to installation of their landscapes. Because many homeowners provided some or all of the installation labor, they were asked to track their work hours as well as expenses. YARDX tabulated participant information. Similar information was not requested from control properties, so as not to potentially influence their water use. As a result, no treatment/control installation cost comparison was conducted. COST DATA QUALITY To ensure a high response and data quality, Xeriscape participants were not given a cash rebate until they had submitted a list of all of their expenses along with receipts and a total of their related work hours broken down by irrigation and other construction work. YARDX reviewed all participant-submitted paperwork and categorized expenses into 11 groups, including plants, hardscape, mulch, walls or drainage, irrigation, home labor hours, contractor hours, contractor costs, non-Xeriscape costs, other Xeriscape expenses, and discounts received. A total of 143 participants from 6 demonstrations submitted landscape cost data. Figure 4.1 shows data contribution by demonstration. Chapter Four 4-1
  32. 32. 40 35 30 Starts / Retrofits 25 20 15 COS-NS = Colorado Springs new start 10 COS-RT = Colorado Springs retrofit 5 DEN-RT = Denver retrofit 0 GRL-RT HGR-NS COS-RT COS-NS DEN-RT FTC-NS FTC-NS = Fort Collins new start Homes 6 15 27 27 34 34 GRL-RT = Greeley combined new start & retrofit HGR-NS = Highlands Ranch new start Figure 4-1: Number of new start (NS) and retrofit (RT) Xeriscapes providing installation costs. computed to compensate for area differences.COST ESTIMATION Figure 4-2 presents the average area of landscapes in each Xeriscape sample. ThisDetermining the average cost of a Xeriscape was figure shows the relative size of landscapes ona goal of YARDX. Categorization of cost data average. Property landscape size was reducedalso enabled determination of the costs of by “dryland” area where appropriate. Drylanddifferent landscape components. Studying cost is defined as an area with sparse, nativedata suggested that extraordinary costs vegetation that receives only naturalassociated with substantial land preparation be precipitation and has no irrigation system. Onlyanalyzed separately from other invoice costs. one retrofit property area (in Colorado Springs)These include costs such as grading that was impacted by this adjustment.generally is conducted by builders, retainingwalls, drainage issues, and non-Xeriscape The retrofit landscapes of demonstrations inexpenses such as fences, dog runs, playgrounds, Greeley, Colorado Springs, and Denverbirdbaths, storage sheds, and large equipment contained areas of pre-existing plants notor tools. replanted. Consequently, nonreplanted areas did not contribute to landscape costs. ThisHomeowners received substantial discounts suggested adjustment of area used infrom nurseries and other providers of landscape computations, for nonreplanted area. However,materials as a result of participation in YARDX. only the Denver demonstration pre-existing areaAs a consequence, one-half of vendor discounts measurements were consistently logged,were considered extraordinary and added to adequate for making adjustments. Some retrofitinvoice costs to simulate typical cost. The homes retained existing turf in their landscapesspecial vendor discounts had been negotiated in small, separate areas difficult to accuratelyspecifically for YARDX participants and were measure. No adjustment was made in Table 4-3not available to the general public. The vendor for nonreplanted areas in the remaining twodiscounts were an additional benefit to retrofit demonstrations, Colorado Springs andparticipants for joining YARDX. One-half of Greeley. The adjustment effect on installationdiscounts for YARDX were considered a cost per square foot for the Denverreasonable estimate of discounts obtainable by demonstration is an increase of 7.9 percent. Anthe general public. estimate of the underestimate of cost per square foot for the Colorado Springs and GreeleyYARDX properties varied in area. retrofit demonstrations is Denver’s 7.9 percentConsequently, cost per square foot was4-2 Installation Cost of Xeriscape

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