I-25 Landscape Master Plan - Laserfiche WebLink

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XERISCAPE DESIGN/PLANT SELECTION INTRODUCTION Aller the lnhlal commlttmenllo beautify a eectlon 01 highway, olher decisions must be mede consld. eting basic landscape design, updating Irrigation systems, desirable plant material characteristics and available maintenance. Evaluation 01 both present and future needs and potential problems Is nacessary as decisions can involve a 3O-t year commitment 10 Ihe chosen components. The mag- nitude 01 this seven mile project prompted a rea- valuation 01 exist/ng highway landscape specs and traditional tandsape Ireatments and resulled in the redirection ot some policies and atloplion 01 new slandards and objectives. The goal 01 Ihese standards/objectives is to maxlmlle water conser- valion and reduce maintenance requirements, yat maintain a high visual qualily landscape. The CUy 01 Denve~s posilive response to the Den- ver Waler Depanment's (DWD) 1986 updated con- servation plan and DWD's request thai the High- way Deparlment consider an allernale landscaping approach locused aUent/on on elli- cient waler management in irrigation 01 urban land- scapes. The decision was made 10 incorporale xe- riseap" waler conservation techniques into the design plans 01 ail 1-25 landscaping projects, This decision is lunher supponed by a 1971 Highway Depanment policy directive to use native or dry- land adaptable plant materials in order to conserve water and reduce maintenance costs, Xerlscape Is a conservation solution aimed alone of the largest single uses of water in urban areas .. landscape irrigalion, landscape irrigation ac- counts lor approximately /illy percent 01 metro Denve~s residenlial waleI use, Xer;scape is a col- lection 0/ conse/'Valion techniques directed 10- wards achieving Ihe most elficient use 01 waler in urban landscapes, The concept Is based on sound horticultural practices used in a way thaI provides a green, aUractive landscape with the leasl amount of water, Landscape aesthetics and greenery are not sacriticed, but water waste Is eliminaled, The allocation of such a large quantity ot waler to Ihe mainlenance 01 'green space' ex- plains the growing public recognition ot the impor- lance of new and beUer ways 10 achieve water conservation in landscaped areas, The use ot xe- riscape concepts can result In water savings at 30-800/." In lunher support of the xer/scape move- ment, the California and Arizona DOTs have been using xeriscape lechniques lor several years. LANDSCAPE DESIGN Design should be oriented to meelthe supplemen- tal irrigation standard set for the 1-25 corridor; No more than 10 - 12 inches ot additional waler can be applied per year, depending on the amounl 01 nat- ural precipitation received each year, However, It is understood Ihat during the germInation or eslab- lishment period, more than t2 Inches of suppll- mental inlgatian may be required. Ultimately, de- sign should be directed to result In a landscape thai will survive and be aesthetically pleasing .. ---, whether there Is waler available for inigatlon or U droughUwater crisis results In restrictions on landscape inigation. To achieve these goals, Ihe seven lundlmenlal prlnciples/sleps of xerlscape are 10 be Incorporated inlo each proieCl's land- scape design, implementation and lollow-up care. An discuss/on ot Ihese sleps lollows: j) PlANNING AND DESIGN Preplannlng during the design process Is the mosllmporlant slep In xeriscape. A planned land- scape design can utilize hall the water 01 a 'tradi- lional' landscape, One key to saving water is In matching, or zoning, plantings 01 similar water re- quirements. In nature, plants group themselves In sites that are conducive 10 their survival and growth; yet In landscaping, pfants wilh different moisture and growth requirements are olten grouped togelher, For example, trees and shrubs should be placed in mulched plantIng bade /0 re- duce Inlgation and malm..nance needs and elimi- nate the problem 01 water compefition Irom the turl. Again. emphasis should be plaCed on group- ing those species with similar water requirements In the planting bed, Another key xeriscape com- ponent which musI be Included in preplannlng is the evaluallon of existing sile conditions, or ml- 15,