LIGHT IMPRINT NEW URBANISM – A FRAMEWORK FOR URBAN AND ENVIRONMENTAL SUSTAINABILITY Tom Low Stephen L. Davis Andres Duany Patrick Kelly Guy Pearlman Georgio Tachiev

AbstractLightImprint(LI)isacomprehensivestrategyaimingtocreateurbanformsthatlielightlyontheland.ItcoordinatessustainableengineeringpracticesandNewUrbanismtechniques,therebyofferingdifferentsolutionsfordifferenttransectzones.NewUrbanismprinciplesofferabetterplanningphilosophybyminimizingtheoverallimpactofthebuiltenvironmentcomparedtoconventionalsuburbansprawl.LI,asaNewUrbanapproach,integratesurbanandengineeringpracticesofferingaframeworkforregional,neighborhood,andblockscaledevelopment.Economicgrowthisensuredwhilepreservingnaturalresources.LIprotectsbiodiversityandreducespollutionandresourcedepletion.Itaddressesconservationofthetwomostcriticalglobalresources:energyandland.

RecentcasestudiesshowLI’sfocusonnaturalsystemsandenvironmentalefficiencywithoutcompromisingdesignpriorities.Communityconnectivityandasuperiorpublicrealmaretheresult.Italsosignificantlylowersconstructionandengineeringcosts.UsingsustainableengineeringpracticesandLIurbanism,waterqualityinthewatershedisensured.Watersheds,whichcontainthehumanhabitat,areessentialforenvironmentalsustainability;mankindmustpreserveservicestheyprovide.Thoseincludewaterquality,waterquantity,biodiversity,andassimilativecapacity.Bypreventingdisruptionanddamageinurbanandsuburbanareas,LIprecludesbiodiversitylossandecosystemchanges.LightImprintNewUrbanism(LINU)isacomprehensiveplanninganddevelopmentframeworkthatemphasizessustainability,pedestrian–orienteddesignandincreasedenvironmentalandinfrastructuralefficiency,whilereducingacommunity’santicipatedconstructionexpensesbyuptoonethirdofconventionalpractices.Onaregionalscale,buildingcompacturbanentitiesreducesthestressandfragmentationofthewatershedcausedbyroads,infrastructureandimperviouscover.Thisstrategypreservestheresourcesprovidedbythewatershedandcreatesenvironmentallysustainablecommunities.Onacommunityandbuildingscale,LightImprintdevelopmentmakescommunitiesmoreeconomicallyvitalbyreducinginfrastructuresuchasroads,publicworksandfacilities.Theimplementationoflightimprintmethodsalsoresultsinasmallerecologicalfootprintofindividualbuildings.Thehydrologicaleffectsincludedecreasedstormwaterrunoffintermsoftotalvolume,peakcapacityandenhancedgroundwaterrecharge,allofwhicharecriticalfactorsforsustainingstreamflowandasaresultaconsiderablylowerfloodanderosionpotentialduetoinducedchangesoftheenvironment.

Introduction

ThepastandcurrentpatternsofgrowthofmanyAmericancitiesareevidencethattheenergyandlandconsumptionwerenotamongstthemostimportantplanningfactors.Continuousandunregulatedpopulationgrowth,urbanization,andindustrializationleadtoconsumptionofexcessiveamountsofenergy,resourcesandlandandcauseirreversibledeteriorationofthewatershedsandtheenvironment.Whilethemajortaskofoursocietyistopromoteeconomicgrowthandequality,notlessimportantistopromotemethodsforconservingenergyandland,minimizingwaste;protectingbiodiversityandlimitingtheairandwaterpollution.Thecurrentplanningprinciplespromotesuburbansprawlpatternsandfavorlow‐densitydevelopmentovercreationofcompactcommunities.Abetterplanningphilosophyisneededtocreateurbanentitiesdesignedontheprinciplesofenergyandenvironmentalsustainability.Theseprinciplesimplementcompactandmixeduseurbanpatterns,increaseddensityandwalkableurbanareasaswelltechnologiesforreducingtheimprintofbuiltenvironment.Planningforsustainabilityshouldalsofocusonpracticesthatlimittheair,water,landpollution,reducegreenhousegasemissionsandclimatechanges,preventdisruptionanddamageinurban/suburbanareas,lossofbiodiversity,andecosystemchanges.

GreenUrbanism(GU)isonealternativeenvironmentalapproachpromotedbylandscapearchitectswhichemphasizesanincreasedpercentageofopenspacewithinadevelopmentsite,typicallyintherangeof60%orgreaterperproject.Greenwayfingersserveastheprimaryorganizingspinesfordevelopment,andstormwaterfiltrationmechanismsareplacedoutsideofandaroundthesegreenspaces.GreenUrbanismdevelopmentsofferfarlessconnectivity,becausestreetsareoftenterminatedtopreventencroachmentongreenwayfingers.Threeproblemsoftenariseinthesedevelopments.First,importantconnectionsaresodisruptedthatfunctionalissuessuchastraversingthesitebecomedifficult.Asecondproblemencounteredisthatlanddevelopmentissuesmakereservingsignificantopenspaceimpracticable.Andfinally,theincreasedrequirementforopenspacemaysoreducetheamountofdevelopablelandthattheprojectmaynotbeeconomicallyfeasible.

LowImpactDevelopment(LID)isanotherpopularenvironmentaldevelopmentstrategyadoptedbysomemunicipalities.TheoriginsofLIDarefoundinconventionalsuburbandevelopmentandincludestormwatermanagementtechniquesthatfilter,store,anddetainrunoffclosetowaterbodies,includingopenspaceconservation,buffersandgrassrooftops(UnitestStatesEnvironmentalProtectionAgency,2000).LIDtechniquescanbeappliedtobothconventionalsuburbanresidentialdevelopmentandcommercialdevelopmentandfornewdevelopment,buildingretrofits,redevelopment,andrevitalization.However,LIDofferssimilarapproachestothesedifferentsortsofdevelopment.Highdensityresidentialdevelopment,suchasatypicalsuburbanapartmentcomplex,isthrownintothesameclassificationascommercialdevelopment,suchasastripshoppingcenter.ThislackofdifferentiationbetweendevelopmentsofdifferentcharactersisonedownfallofLID.Furthermore,LIDsuggeststhatinsteadoftypicalgridiron

layout,loopsandlollipopspatternsmayresultinreductionoftotalimperioussurfacearea(PrinceGeorge'sCounty,1999),byupto26%.AlthoughLIDintroducescostefficientstrategiesforstormwatermanagement,LIDprioritizesvariousenvironmentalfactorsoverurbanplanningprinciplesandmayasaresultpromotesprawldevelopmentpatternsbyignoringsuchimportantrequirementsasconnectivity,compactness,walkability,andmixed‐use.

On‐sitedesigntechniques,suchasBestManagementPractices(BMP)areusedbyLIDforimprovingstormwaterquality.BestManagementPracticesproposedbytheEPA(Nisenson,2005)typicallyfocusesonengineeringandwaterqualityissuesofstormwaterrunoffratherthanplanninganddesignforaddressingmethodsforstormwatertreatment.However,problemsarisewhenBestManagementPracticesdesignedtosolvesuburbanengineeringissuesareappliedtomoreurbancommunities.Forexample,compactdevelopmentsufferswhenBMPsdictatetheneedforstormwaterdetentionareasinfrontof,orbesidebuildingsonsite.Thisapproachcanharmacommunity’ssocialconnectivityandmayeveninterferewithretailmerchandizingneedsandfeasibility.

ComparedtoconventionalengineeringpracticesNewUrbanistConventionalEngineeringaccommodatesabroaderrangeofdevelopmentstandardsnecessaryforcommunity‐orienteddesign.Inrecentyears,thedevelopmentindustryhasbeguntoshiftfromtheconventionalsuburbanmodeltowardstheNewUrbanmodel,whichadvocatesthedevelopmentofcompact,mixed‐use,pedestrianfriendlycommunities.Muchofthisshifthasemergedfromtheneedtobetteraddressenvironmentalandcommunitygoalsandtoreconcilethedevelopmentindustrywithlandconservationorganizations.TheNewUrbanmodelallowsresidentstogreatlydecreaseuseoftheircars,clearlyyieldenvironmentalbenefits,butsuchdevelopmentsalsohaveagreatnumberofotherenvironmentalstrengths.TheU.S.GreenBuildingCouncil(USGBC),whichdevelopedtheLEED(LeadershipinEnergyandEnvironmentalDesign)GreenBuildingRatingSystem,hasrecentlyrecognizedthisfact.InpartnershipwiththeCongressofNewUrbanism(CNU)andtheNaturalResourcesDefenseCouncil,theUSGBCusedtheprinciplesofNewUrbanismtodevelopanewratingsystem,LEEDforNeighborhoodDevelopment.Thenewsystemintegratestheprinciplesofsmartgrowth,urbanism,andgreenbuildingintothefirstnationalstandardforneighborhooddesignandprovidesahighlevelofenvironmentalbenefits.

LightImprintNewUrbanism

Thecontinuousexpansionoftheinfrastructureofthehumansocietyincreasesthestressandimpactsthenatural,sustainableconditionsofthewatersheds.Inordertoanalyzethedegreeofwatersheddeteriorationcausedbycontinuousexpansionofthehumanhabitat,onemustunderstandtheimpactonthewatershedcausedbydifferentdevelopmentpatterns:rural,suburbanandurbanhumanhabitats.Theimpactsofurbanizationonwatershedsismostlycausedbyimperviouscoverandresultsinelevatedlevelsofwater,airandsoilpollution,deteriorationoftheecosystemanddecreasingbiodiversity.Theurbanizationmaycauseelevatedlevelsoflawnnutrients,urbanpesticides,rooftoprunoff,firstflushofstormwater,contaminationbyheavymetals,suspendedanddepositedsediments,andbiocontamination.Thegrowthofthehumanhabitataffectsthewatershedsquantitativelyandqualitatively:

• Integral:Theimpactonthewatersheddependsonthecompositeeffectoftheurbanzoneswithinthewatershedboundariesandcomprisingahumansettlement.Thus,theeffectwillbecumulativeandwhilehighlyurbanizedareaswillhaveagreaterimpactonlocalscale.However,onregionalscaletheimpactwillbelessseverecomparedtosprawldevelopmentpatterns.TheprinciplesofNewUrbanismofferabetterplanningphilosophyforminimizationoftheoverallimpactofthebuiltenvironment.• Differential:Theimpairmentofawatershedisproportionaltotheurbanizationintensityandtheextentofbuiltinfrastructure,i.e.,typeofhumanhabitat/urbanzones:ruralareasmayhavelessimpactonthewatershedscomparedtourbancoreareas.Nevertheless,theimpactoftheinfrastructurecanbereducedbyapplyingavarietyoftechniques.Maintainingthewatershedinitsnaturalconditionisthekeyfactorforensuringcontinuedqualityservicesofthewatersheds(expressedinpreservedbiodiversity,waterqualityandquantity,andassimilativecapacity).Theexcessivelanduseandbuiltinfrastructureencouragedbysprawlcausesfragmentationandincreasestheimpairmentoftheservicesandresourcesprovidedbywatersheds.TheNewUrbanismisamethodologythatoffersacomprehensiveapproachtobetterutilizationofthenaturalresources,communitydevelopmentandcreatespleasantandlivablecommunitiesByprioritizingthesedesignandplanningissues,NewUrbanistdevelopmentoffersmulti‐facetedenvironmentalandcommunityplanningbenefits,unlikemoreisolatedenvironmentalapproaches.

OneofthegreateststrengthoftheNewUrbanismintheareaofsustainabilityisthedesignofcompactcommunities,whichhaveabetterperformanceontheregionalscalefortwoimportantreasons.First,compactcommunitiesrequirereducedinfrastructure,andsecond,theycauselowerstressandfragmentationoriginatingfromimperviouscover.Thesignificanceofcompactnesshasbeenshowninarecentstudyby(Long,Tachiev,&Yaari,2007),whichanalyzed5citieswithintheMiamiMetropolis,includingCoralGables,Doral,Hialeah,MiamiandSweetwater.Thestudyincluded281CensusBlockswithpopulationof384,134on31,617acresofland.Foreachcensusblockthepopulationdensitywasdeterminedbydividingpopulationbyareaofcensusblockandtheareaofroadsperpopulationwasdetermineddividingthetotalareaofroadsperpopulation(Figure1),whichresultedinalogarithmictrend.

Figure1Effectofpopulationdensityonroadsharing

Thefigureillustratestheextentofinfrastructureexpressedintermsofroadsneededperpersonasafunctionofthepopulationdensity.Theneedforroadsperpersongrowslogarithmicallyasthedensitydecreases.Whilenotshownhere,similaristheeffectwithotherpublicworkssuchaswater,sewerandpowerlines.TheNewUrbanistdevelopmentsaremodeledafterthebestperformingtraditionalcommunitiesandinadditiontoconsiderablereductionofinfrastructureonregionalscale,NewUrbanistdevelopmentsresultinimprovedwatershedprotectionbyreducingthetotalimperviousareas.TheconnectednetworksadvocatedinNewUrbanistdevelopmentcreateasymbioticconnectionbetweenbuiltandnaturalenvironmentandprovidecomprehensiveenvironmentalprotectiononregional,neighborhoodandblockscale(outlinedintheCharteroftheNewUrbanism1).TheCharterprioritizesdiversity,walkabilityandconnectivity,allofwhichcontributetothecreationofsustainableneighborhoods.LeadingplannerAndresDuany,aprincipalofDuanyPlater‐Zyberk&Company,describesthelayoutofatypicalNewUrbancommunityasan“open‐meshnetwork”whereafine‐grainsystemofconnectedstreetsmitigatestrafficcongestionandreinforcescommunityconnections.

Furthersupportingtheconceptsofurbansustainability,therearenewlydevelopedtechniquesfor“LightImprintNewUrbanism”(LINU),whichaimto“lielightlyontheland”bycoordinatingengineeringpracticesandNewUrbanistdesignpractices.Itenablesdeveloperstoconsiderenvironmentalandpreservationfactorswithoutcompromisingdesignprioritiessuchasconnectivityandthepublicrealm.LikeallNewUrbanplanning,LINUrespectssiteterrainandtopographywhileitprioritizespubliccivicspace.Additionally,LINUoffersarangeofcutting‐edgeenvironmentalstrategiesfordifferinglandscapesandurbanconditions.LINUplanning

1http://www.cnu.org/cnu_reports/Charter.pdf

introducesatoolsetthatdealswithstormwaterrun‐offthroughnaturaldrainage,conventionalengineeringinfrastructure,andinnovativeinfiltrationpractices.Thesetoolsaretobeusedcollectivelyatthesector,neighborhood,andblockscale.Thecombinationoftoolsareadjustedaccordingtotheappropriatenessoftheiruseineachtransectzone.

Thistoolsetnotonlyoffersagreatrangeofenvironmentalbenefits,butcanalsosignificantlylowerconstructionandengineeringcosts.Byusingdifferenttoolsineachtransectzone,LINUisnotlimitedtoasingleapproachforenvironmentallysensitivedevelopment.Rather,itoffersarangeofcontext‐sensitivedesignsolutionsthatultimatelyworktogetheronthecommunitylevel.ThusLINUreducesinfrastructureontheneighborhoodscaleintermsofroads,publicworksandfacilities.Ontheblockscale,theimplementationoflightimprintmethodsresultsinreducedecologicalfootprintofindividualbuildingsandreducedstormwaterrunoff.

GriffinPark,aDPZ‐designedtraditionalneighborhooddevelopmentinGreenville,SouthCarolina,offersoneexampleofLightImprintNewUrbandevelopment.WhiletherehavebeennumerousstudiescomparingConventionalSuburbanDeveloment(CSDs)withTraditionalNeighborhoodDevelopment(TNDs),therehavebeenfewcomparingstandardTNDsto“LightImprint”TNDs.TheDPZCharlotteofficerecentlytookonsuchaproject,usingGriffinParkasacasestudy.GriffinParkissituatedatthehighlytraveledcrossroadsofWestGeorgiaRoadandForkShoalsRoad,fifteenmilessouthwestofdowntownGreenville.Theareahasbeenheavilydevelopedasthecityhasexpanded,andmuchofthelandsurroundingthesitehasbeendevelopedintoconventionalhousingsubdivisions.GriffinParkwillofferanalternativetothissprawldevelopment,andwillgiveresidentsachancetoliveinamorecommunity‐orientedatmospherewithpublicspace,recreationalofferings,andretailwithinwalkingdistanceoftheirhomes.Whencompleted,GriffinParkwillincludemorethanonethousandsingle‐familyhomesaswellaslarge‐scaleretailofferings.Themajorityoftheretailactivitywillbewithinthetowncenteratthemajorintersection,whichwasoriginallyzonedforbig‐boxretaildevelopment.Thebig‐boxcomponentshavebeenre‐designedtobeintegratedwithapedestrian‐scaledMainStreet,linedwithsmaller‐scaledretailestablishmentsandlive/workunits.ThisMainStreetdevelopmentspinewillconnectthevariousneighborhoods,eachofwhichwillhaveitsownsmallercommunitycenterfeaturingaplazaorasquare.Additionally,eachneighborhoodwillhaveauniquelandscapecharacteranddesignadheringtothesite’stopographyandnaturalfeatures.BeyondGriffinPark’stowncenter,largersingle‐familyhousesareinterspersedwithtownhousesandcarriagehousesalongstreetsdesignedforpedestrianactivity.ManyofthesestreetsfollowthecurvesoftheReedyRiver,preservingthesite’swetlandsandprovidingabuffertonearbydevelopment.Thetownplanalsopreservesgreenspacebyincludingpubliccivicspacessuchasparks,playgrounds,trails,andsportsareas.Bypreservingopenspaceaswellasservingasanexampleofcompact,mixed‐usedevelopment,GriffinParkisenvisionedasaprecedentforhowtheGreenvilleareacanaccommodatefurthergrowth.

Figure2MasterplanofGriffinPark,leftimagerepresentsConventionalTNDMasterplanandtherightimagerepresentsLightImprintTNDMasterPlan

Thefigureabovecomparesthemasterplanbeforeandaftertheapplicationoflightimprintengineering.LandscapearchitectGuyPearlmananddesignerPatrickKelly,bothoftheDPZCharlotteofficedevelopedtheLINUmodelforGriffinParktocreateanenvironmentallysensitivecommunity,preservematuretreestands,andlowertheconstructioncostsforthefirstdevelopmentphase.TheconventionalTNDengineeringplanisengineeredforbothcountyreviewandbiddingpurposes;itreachesanextensivelevelofdetail.Thelight‐imprintengineeringplanisbasedonmanyofthevariablesdevelopedintheconventionalplan.Addedconsideration,however,isgiventoenvironmentalandpreservationfactors.Thosefactorsenhancetheoverallvalueofthecommunityandlowerthetotalcostofconstruction.EnvironmentalstrategiesatGriffinParkincludedtheintroductionofraingardensandatreeprotectionfence.Theintroductionoftheseelementsallowedforthedevelopment’sundergroundpipingsystemaswellascurbsandgutterstobedownsizedtherebylesseningtheenvironmentalimpactofthedevelopmentandsavingsignificantsumsonconstruction.

Inordertoachievethedesiredgoalsofthelight‐imprintTNDplan,atreeprotectionfenceisintroducedintheerosioncontrolphasetoprotecttheexistingmaturetrees.Thatstrategyresultsina27%costincreasewhencomparedwiththeconventionalproposedmethod.Yet,acostsavingbetweenthetwomethodswasfoundinthestormwatermanagementphase.A50%costsavingswouldbeachievedbythefollowingsimpleactions:1)Omissionofcurbandgutterinstrategicareas;2)Reductionintheamountofpiperequiredaswellasreductionintheirlengthsandsize;3)Reductionintheneedforinletstoundergroundpipes;and4)Theintroductionofsmallerraingardensthroughoutthecommunitytoreplacetheonelargeretentionpond.

Figure3EngineeringinfrastructureofGriffinPark,leftimagerepresentsConventionalTNDMasterplanandtherightimagerepresentsLightImprintTNDMasterPlan

Thefigureaboveshowstheengineeringinfrastructureforeachoftheseplans.Theintroductionofraingardensalsoaddsaestheticallypleasingnaturalareasandneighborhoodrecreationareas.RaingardenswouldremoveagreateramountofpollutantsfromrunoffbeforethepollutantscouldreachtheReedyRiver.Theraingardenspermitgroundwaterrecharge,thuscontributingtotherestorationofthenaturalwatercycle.Also,therearetworoadpavementissuesthatreducecosts.First,building24feetwideroadsinsteadof26feetwideroadsresultsinasignificantreductionoflandcoverageandpavingcosts.Second,substitutingcrushedstoneinplaceofasphalt‐pavedalleyssavesover20%indevelopmentcosts.Significantattentionandimprovementinwaterqualitycanbeachievedbypermeablepavements.

Implementingthelight‐imprintengineeringmethodresultsinover30%costsavingsinactualconstructiondollarsforthefirstphase.Thatcostsavingisinadditiontotheaddedvaluerealizedbythepreservedmaturetreesandcommunalraingardens.MunicipalitiesreviewingNewUrbancommunitiesareofteninterestedinembracingtheNewUrbanistapproach;however,theirgoverningbodiesmaybeconservativeregardingacceptanceofdifferentstandards.Problemsarisewhendesignersattempttoovercompensatewithstandardsanddesign.Thisovercompensation,or“goldplating,”ofinfrastructurehasadverseeffectsontheabilitytosuccessfullyimplementaNewUrbancommunity.Projectdelaysandadditionalinfrastructurecostcanultimatelypreventtheimplementationofagoodcommunitydevelopment.LightImprintNewUrbanismoffersamoremanageablealternativebycoordinatinginnovativeengineeringpracticeswiththeNewUrbandesignapproachesinspecifictransectzones.Thisstrategywilleaseimplementation‐whichiscrucial,giventhatcurrentlyonlyalimitednumberofNewUrbanistpractitionershavesignificantimplementationexperience–andalsooffergreatenvironmentalbenefits.InordertohavetheLightImprintapproachembracedbyadvocatesofNewUrbanismwithinmunicipalitiesandthedevelopmentandbuildingindustry,itisimportanttohavetheLightImprintmodelpresentedasacomprehensivestrategywhichsupportstheNewUrbanistdesignofstreetandlotlayoutalongwithotherstandardpracticesforcommoninfrastructureelementsincludingwaterandsanitarysewer.

Figure4Proposedreductionsofpavementandcurbandgutter.

ForLightImprintNewUrbanism,engineeringhydrologybecomescritical.Thesurfaceandsubsurfaceinfrastructurecanremoveboththesolubleandfineparticulatepollutantsthatoccurwithinurbanrunoff.However,soilanalysesareneededtoverifythatsoilisincompliancewithraingardenabsorptionrequirementsandtoconfirmthatsmallerpipesizeissufficientforthesystem.EventhoughacomprehensiveapproachworksbestwhenapplyingtheLightImprintmodel,itisalsoimportanttomakesuresomeofthetechnicalissuesworkwithintheframeworkofgoodengineeringpractices.TheLINUstrategyofallowingmorestormwatersurfacesheet‐flowacrosspervioussurfacestoencourageonsiteabsorptionandtoreducethetypicalnumberofdraininletsandlengthofdrainagepipe.Thistechniqueisgood,butusersshouldstillapplytherule‐of‐thumbofa400linearfeetmaximumdistancefromadraininletusingcurbandgutter.Additionalwaysforreducingtheinfrastructureincludessheetflowingthestormwaterthroughthefiltrationlandscapingdirectlyintoexistingnaturaldrainagesystems,thuseliminatingswales

forsomelotsandstreetsalongtheneighborhoodperimeter.Roofwatercanbepipedintothestorageareadirectly,addingareasfromwhichtheflowcanbeattenuated.

Fieldsupervisionandon‐goingmaintenanceissuesarealsoamajorfactortoconsider.Additionalsupervisionisneededtomakesuretheraingardensareconstructedproperly.Properdesignassuresthatwaterdoesnotbypassthedrainagearea.Theuseofpropermaterialsandinstallation,includingperforateddrainpipesmustandraingardenplantmaterialwhichisindigenousandwatertolerantensureslonglifetimeoftheinstallation.Inaddition,theinstallationshouldbecompatiblewiththedesiredcommunitycharacterandmaintenanceprogram.Ifperviousroadsurfacesarebeingconsideredforalleys,lanes,andstreetswithoutcurbandgutter,thenmeasuresareneededtostabilizetheroadandalleyshoulderstopreventsoilerosionandtirerutting.

AnotherexamplewhichwillprovidetheLowCountrywithaviablealternativetosuburbansprawlisHabersham,SClocatedsouthofCharleston.Thetownispositionedalonganinletlessthanamilefromtheintercoastalwaterway.Withitssizabletowncenter,Habershamwillserveastheurbanhubforsurroundingvillages.Thearchitectureoftheprojectrespectsthelocalvernacular,takingintoaccounttheexpertmethodsemployedbytraditionaldesignsforventilationandcooling.Theselogicalmethods,forgottenorignoredbyconventionalbuilders,are

mandatedbythearchitecturalcodesthataccompanytheplan.

Figure5NocurbLINUboulevardinHabersham,SC

Thebuildingtypesaredesignedandlocatedontheplanaccordingtotheirlevelsofurbanism.Alongwiththedifferentstreetsections,thebroadassortmentofbuildingtypeswillprovideavariedandauthenticenvironment.Thispermitsasingledevelopmenttocaptureawidevarietyofhome‐buyermarketsegments.Inaddition,thecompatibilityensuredbythecodemaintainshighpropertyvaluesandtheflexibilityofswitchingtothemostmarketablebuildingproductwithoutredesigningtheentireplan.Winnerofthe2004PlatinumAwardintheBestinAmericanLiving(BALA)Competition,sponsoredbyProfessionalBuildermagazineandtheNationalAssociationof

HomeBuilders.

Figure6Abuiltexampleoflightimprintstormdrainage,Habersham,SC

TheLINUisstillanexceptionratherthanthenorm.DesignersanddevelopersmaynotbeabletoimplementallLightImprintelementsrightaway,buttheycouldimplementLINUinincrementalstagesascertaincomponentsareapproved.Duetothepaceofdevelopmentandtheneedforprojectstosucceed,itisespeciallyimportanttoplanforincrementalimplementation.Acomparisonbetweenthetwoengineeringmethodsbasedonerosioncontrolmeasures,stormwaterinfrastructure,andpavementwidthandmaterialsforthefirstphaseofthedevelopmentof42acresand174lotsshowsabouta30%lowercostfortheLINUmethod.ForGriffinPark,theLINUcasestudyforthefirstphasewascompellingenoughtoleadthedevelopmentteamtoapplyLINUtechniquesevenaftertheconstructionhadstarted.ThecasestudyalsoconvincedustoworkwithlocalstakeholdersandapprovalagenciestoholisticallyapplytheLINUapproachforthenextphases.TheapplicationoftheLINUmethodsbasedontransectzonescanbefurtherappliedtoreducetheimpactonwatershedsonalargerregionalscale.

Conclusion

GriffinParkisatraditionalneighborhooddevelopmentdesignedbyDuanyPlater‐Zyberk&CompanywhichoffersoneofthefirstexamplesforLINUdevelopment.Thefirstphaseofconstructionofferedanopportunitytodocumenttheevolutionofthisenvironmentallysensitivecommunity;whichlieslightlyonthelandbycoordinatingengineeringpracticesandNewUrbandesigntechniques;preservesmaturetreestands;andlowerstheconstructionandengineeringcostswithoutcompromisingdesignprioritiessuchasconnectivityandthepublicrealm.TheLINUstrategyallowedmorestormwatersurfacestoencourageonsiteadsorptionandtoreducethetypicalnumberofdraininletsandthelengthofthedrainagepipesystem.Theintroductionofraingardensallowedforenhancednaturalbiodegradationofpollutantsfromrunoff.

Additionally,thelotsandstreetsalongtheneighborhoodperimeterdidnotneedmostoftheswalessinceaportionofthestormwaterwassheetflowedthroughthefiltrationlandscapingdirectlyintoexistingnaturaldrainagesystems.Thesetechniquesallowbestprotectionofthewatershedhostingthisdevelopmentbymaintainingthelandinitsnaturalconditionandminimizationoftheimperviouscover.ThemostcompellingfactorforusingtheLINUdesignprinciplesistheimprovedaffordabilityofthecommunitybyanoveralldecreaseinconstructioncosts.TheLightImprintdevelopmentstrategyresultedina27percentcostincrease,withtheintroductionoftreeprotectionfences.Yet,a50percentcostsavingsoccurredwith:1)Thereductionofcurbsandgutters;2)Thereductioninthenumberofstormwaterpipesandinlets;3)Thereductioninperviouspavementinalleysandstreets;and4)Theintroductionofraingardens.TheLightImprintNewUrbanismframeworkenhancesexistingurbansustainabilitypracticesandpromotespreservationofwatershedsonalargeregionalscale.Thedesignofthiscommunitygivesandexampleofsolvingthemostdifficultplanningandengineeringquestionabouthowtopreserveandrestorethenaturalresourcesandservicesderivedfromthewatershedwhileensuringhumanwell‐being.

WorksCited

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Nisenson,L.(2005).UsingSmartGrowthTechniquesasStormwaterBestManagementPractices.RetrievedMarch2007,fromSmartGrowth:StormwaterBestManagementPracices:http://www.epa.gov/smartgrowth/pdf/sg_stormwater_BMP.pdf

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UnitestStatesEnvironmentalProtectionAgency.(2000).LowImpactDevelopment.Washington,DC20460:OfficeofWater.