Guidance n Calculatin f Outdr Water Use Reductins fr LEED Canada fr Hmes Credits SS 2.5 and/r WE 2.3 This guidance dcument prvides an verview f the calculatin prcedures fr estimating the reductin in utdr water use achieved frm sustainable landscaping and irrigatin system designs. These calculatins must be cmpleted if the prject team intends t take credit fr SS 2.5 r WE 2.3, even if the prject des nt intend t install an irrigatin system. These calculatins must be perfrmed by a landscape prfessinal, which includes individuals with certificatin, licensure, frmal training (higher educatin), r at least 0 years f prfessinal experience. If an irrigatin system is installed, it shuld be designed and installed by an irrigatin prfessinal. This may r may nt be the same persn as the landscape prfessinal. The landscape prfessinal r irrigatin specialist must sign the Accuntability Frms fr SS 2.5 (and WE 2.3), and submit the calculatins t the LEED Canada fr Hmes Prvider. Alternatively, he/she may cmplete the LEED Canada fr Hmes Calculatr fr Percent Reductin in Outdr Water Use, including the signature, and submit this t the Prvider, in lieu f the Accuntability Frm. The same calculatin is perfrmed in SS 2.5 and WE 2.3. Full pints must be earned in SS 2.5 befre any pints are earned in WE 2.3. WE 2.3 cannt be pursued unless SS 2.5 is pursued. There are 3 parts t this guidance:. A simple explanatin f the methd fr calculating the reductin in verall utdr water use 2. A table describing the factrs K S, K MC, IE, and CF 3. Example calculatins Terminlgy Please nte that sme f the terms used in this guidance replace terms used in the LEED Canada fr Hmes Rating System and Reference Guide. This was dne t mre accurately describe the cmpnents f this calculatin, and updated versins f the Rating System and Reference Guide will incrprate this new terminlgy. Terms used in Rating System and Reference Guide Irrigatin water usage Design case usage Baseline usage New terminlgy Estimated utdr water demand Design case utdr water demand Baseline utdr water demand Canada Green Building Cuncil -- January 2009
Part Simplified Explanatin f Methd fr Calculatin f Outdr Water Use Reductin The calculatin prcess required t demnstrate cmpliance with SS 2.5 and WE 2.3 can be summarized in fur steps, which are prvided belw. Fr mre infrmatin, please review A Guide t Estimating Irrigatin Water Needs f Landscape Plantings in Califrnia (r WUCOLS dcument), available frm the CA Dept f Water Resurces under the Publicatins link at: http://www.wue.water.ca.gv/landscape/ Step. Calculate the utdr water demand fr the landscaping fr the baseline. Definitin: The baseline utdr water demand is the amunt f water that wuld be lst thrugh evaptranspiratin if the given landscaped area were planted with a reference grass. The baseline depends n: Landscaped Area. This refers specifically t the designed area f landscape sftscape. (D nt include the huse, garage, patis, etc. Als d nt include existing landscaped areas.) A larger area requires mre water. Reference Evaptranspiratin Rate (ET0) fr yur regin. The ET0 value fr July must be used. The ET0 is reginally specific. A regin that is cl r humid will have a lwer ET0 than ne that is ht and dry. ET0 is based n the water lst frm a medium-height, cl-seasn grass grwing in an pen field in the regin. Typical ET 0 values are ften available frm a lcal r state Department f Agriculture. Or cntact an expert: www.irrigatin.rg/gv/et_list.htm The mnth f July is used, because it is generally the mnth with the highest water needs. The Baseline utdr water demand is calculated with the fllwing equatin (perfrmed autmatically by the LEED Canada fr Hmes Calculatr): Baseline utdr water demand = Landscaped Area * ET 0 * 0.62, Where: Landscaped Area is in ft 2, and ET 0 is in inches per mnth. The 0.62 is a cnversin factr (cnverts ft 2 *in/m int gal/m). If the landscape prfessinal has difficulty finding the ET fr the regin, please cntact yur Prvider. Canada Green Building Cuncil -2- January 2009
Step 2. Calculate the utdr water use fr the landscaping fr the Design Case. Step 2a. Divide the Landscaped Area int landscape znes. Definitin: Fr the purpses f this dcument, a landscape zne is an area within which all plantings will require the same amunt f water. Znes may r may nt be divided int separate parcels n the actual lt. In this calculatin the landscaped area must be divided int znes, as apprpriate. If there are slightly different water needs within a zne, the calculatin fr that zne shuld be based n the highest water needs within it. T avid this, when designing landscape znes, take int accunt variatins in: Types f plants Micrclimates (e.g., differences in shading) In additin, the fllwing affect irrigatin efficiency and shuld als be cnsidered fr each zne. Type and efficiency f irrigatin systems Irrigatin system cntrls The fur variables abve affect utdr water use, and each is characterized by a different factr that is used in the calculatin. Descriptins and example values fr each factr are given in Exhibit. These factrs are used in the equatin in Step 2b. Step 2b. Calculate the utdr water use fr each landscape zne. The general calculatin fr utdr water use is as fllws: Outdr water use = (Landscaped Area * ET0 * KS * KMC / IE) * CF * 0.62 Where: ET 0 = reference evaptranspiratin rate (inches per mnth) K S = species factr, K MC = micrclimate factr, IE = irrigatin efficiency, and CF = cntrl factr This calculatin must be cnducted fr each zne, using values fr Landscape Area, KS, KMC, IE, and CF that are specific t each zne. Please nte that CF is nly applicable if there are cntrls. If there are n cntrls, CF shuld equal.0. If there is n irrigatin system, use the apprpriate default IE value prvided in Exhibit. (IE is calculated autmatically by the LEED Canada fr Hmes Calculatr). Canada Green Building Cuncil -3- January 2009
Step 2c. Determine the ttal utdr water use fr the Design Case. Sum the utdr water use frm all f the znes, using the fllwing frmula (perfrmed autmatically by the LEED Canada fr Hmes Calculatr): Design Case utdr water use = utdr water use fr zne + utdr water use fr zne 2 + utdr water use fr zne 3 + (all znes) Step 3. Calculate the percent reductin in utdr water use Use the utput frm Step and Step 2 t calculate the verall estimated percent reductin in utdr water use fr the Design Case (perfrmed autmatically by the LEED Canada fr Hmes Calculatr): Percent reductin = (Design Case utdr water use / Baseline utdr water demand) * 00% Step 4. Determine the number f LEED pints Refer t Table 5 f the LEED Canada fr Hmes Rating System (r Table 3 in the SS 2 sectin f the LEED Canada fr Hmes Reference Guide) t determine hw many LEED pints the prject team has earned based n the result f Step 3 abve (perfrmed autmatically by the LEED Canada fr Hmes Calculatr). Additinal pints and exemplary perfrmance The SS Technical Advisry Subcmmittee has ruled that prjects pursuing credit in SS 2.5 and WE 2.3 can earn additinal credit in the fllwing ways: If a prject meets SS 2.2 parts (b), (c), (d), and (e), ne additinal pint may be cunted in ID 3. If a prject exceeds the maximum value in WE 2.3, exemplary perfrmance pints may be earned (t be cunted in ID 3) accrding t the fllwing: ne pint fr 65% reductin tw pints fr 70% reductin three pints fr 75% reductin fur pints fr 80% reductin Canada Green Building Cuncil -4- January 2009
Part 2 Example Values f K S, K MC, IE, and CF See example values in Exhibit Canada Green Building Cuncil -5- January 2009
Exhibit. Descriptin and Example Values f K S, K MC, IE, and CF Fr further guidance, see A Guide t Estimating Irrigatin Water Needs f Landscape Plantings in Califrnia ( WUCOLS dcument), available frm the CA Dept f Water Resurces under the Publicatins link at: http://www.wue.water.ca.gv/landscape/ Factr Descriptin Range f Values The species factr reflects the amunt f water that the species f plant needs. Guidance in Chsing Values 2 If the landscape prfessinal is familiar with the K S values fr the species planted, use thse values. Otherwise, use the values frm Table 6 in SS 2.5 as fllws. Fr a vegetatin type, chse: K S K MC A high value is used fr plants that need a lt f water. A lw value is used fr plants that need little water. As a general rule f thumb, species requiring the fllwing amunts f water are designated as fllws*: 70-90% ET : High K s 40-60% ET : Mderate K s < 30% ET : Lw K s *Surce: the WUCOLS dcument Base estimates n expected demand when plants are fully mature. The micrclimate factr describes hw cnditins such as sun and wind affect the demand fr water. A high value is used fr areas in direct sun, high winds, r receiving heat frm reflective surfaces. A lw value is used fr areas in shade r prtected frm the wind. 0.2-0.9 3 0.5-.5 Fr mst situatins, chse frm 0.8,.0, r.2 4 The lw value fr a species that needs less water than mst plants f that type. Fr example, fr drught-resistant shrubs that use little water, chse the Lw value fr Shrubs: 0.2 The average value fr a species that needs a typical amunt f water fr that type. Fr example, fr a flwerbed with typical water needs fr flwers, chse the Average value fr Grundcver: 0.5 The high value fr a species that needs mre water than mst plants f that type. Fr example, fr a fruit tree that needs t be watered ften, chse the High value fr Trees: 0.9. If a landscape zne is planted with different species that have different K S values, use the highest K S value fr the calculatin. Als, this indicates that the landscape design culd be imprved. Cnsider substituting the highest K S species with a lwer K S species. If the landscape prfessinal is familiar with hw K MC values are applied, use thse values. Otherwise, use the values frm Table 7 in SS 2.5 (r Table 3 in WE 2.3) as fllws. Chse: Lw, K MC = 0.8, if zne shaded, n the nrth side f a building, and/r prtected frm the wind (e.g., curtyards). Average, K MC =.0, if zne smetimes shaded and in mderate winds. High, K MC =.2 if zne sunny, windy, receiving reflected heat, and/r n the suth side f a building. 2 The Tables referenced are in the Rating System. These tables are numbered differently in the Reference Guide. 3 Ks values < 0.2 are nt acceptable. Plants such as drught-resistant, native species can appear stressed (e.g., wilted) during lng perids f ht, dry weather. Althugh these species survive in the wild, hmewners may chse t water them, s that they appear mre healthy. Cnsequently, the water use fr these plants is nt 0. 4 Fr extrardinary cnditins, the fllwing may be used: Extremely well-prtected and shaded, K MC = 0.5; extremely sunny and windy, K MC =.5. Canada Green Building Cuncil -6- March 20, 2009
IE CF The irrigatin efficiency describes hw much f the water that the irrigatin system uses actually reaches the plants, and hw evenly it is distributed. A system is mre efficient if: ) The type f system distributes water directly t plant rts, instead f lsing water t wind r evapratin. 2) There is gd spacing in the system, s that (fr example) plant is nt watered by 2 nzzles. 3) The system nzzles are well pressurized and distribute water evenly. Irrigatin systems can include cntrls (e.g., a misture sensr, r a weather-based cntrl). These increase efficiency. 0.5-0.9 0- IE is autmatically calculated by the LEED Canada fr Hmes Calculatr. If nt using the LEED Canada fr Hmes Calculatr: If n irrigatin is installed, use IE = 0.65 fr znes with K L < 0.33 (where K L = K S * K MC ), and IE = 0.4 fr znes with K L 0.33. The fllwing (based n WE 2.) are the 6 efficient distributin measures : ) Head-t-head cverage 2) A central shut-ff valve 3) A submeter 4) Pressure-regulating devices fr ptimal pressure and preventing misting 5) High-efficiency nzzles, with an average distributin unifrmity (DU) 0.70 (verified by manufacturer s dcumentatin r 3 rd -party testing). Drip systems autmatically qualify. 6) Check valves in heads. Fr an irrigatin type listed in Table 8 in SS 2.5 (r Table 4 in WE 2.3) chse: Lw if 3 rd party verificatin f irrigatin system was nt dne, the irrigatin system was nt installed by a WaterSense Irrigatin prfessinal, and the system includes < 3 f the distributin measures. Example: Fr unverified drip system nt installed by WaterSense prfessinal, with 2 distributin measures, IE = 0.70 (Lw fr drip). The average f Lw and High if system was installed by a WaterSense prfessinal r verified by a 3 rd party as distributing water evenly, OR if 3 f distributin measures are installed. Example: Fr drip system installed by WaterSense prfessinal, with 2 distributin measures, IE = 0.8 (Average f 0.7 [Lw] and 0.9 [High]). High if 6 distributin measures installed; OR if system installed by a WaterSense Prfessinal r 3 rd party verificatin fund that water distributed evenly AND if 3 distributin measures. Examples: Fr verified drip system with 3 distributin measures, OR fr an unverified drip system with all distributin measures, IE = 0.9 (High fr drip). If n cntrl is installed, use CF =.0. If a cntrl is installed: CF = (fractin f verall irrigatin water saved by cntrl). Fr example, fr a misture sensr that saves 0% f all irrigatin water, CF = (0.) = 0.9. Cntrls must be installed at time f certificatin. Water savings must be shwn by manufacturer s dcumentatin r calculatins. Canada Green Building Cuncil -7- March 20, 2009
Part 3 Example Calculatins Example A hme in Sacrament, CA has a 000 ft 2 rectangular yard. Half f the yard is planted with bushes that are nt drught tlerant, and that have typical water needs. The ther half is planted with drught-resistant, native wildflwers that will rarely require water beynd precipitatin. The entire yard is in partial shade, and winds are nrmal. Rtrs are installed t water the bushes. The system includes flw-cntrl sensrs that result in 5% water savings, accrding t dcumentatin frm the manufacturer. The system was installed by an irrigatin prfessinal. This persn was nt WaterSense certified, and it was nt verified by a 3 rd party as distributing water evenly. The irrigatin system includes 3 f the 6 listed distributin measures. There is n installed irrigatin system fr the wildflwers. Frm A Guide t Estimating Irrigatin Water Needs f Landscape Plantings in Califrnia (the WUCOLS dcument), fr July in Sacrament, CA: Daily Average ET 0 fr Sacrament in July = 0.28 inches ET 0 fr mnth f July = 0.28 in/day * 3 day/july = 8.7 in/mnth The LEED Canada fr Hmes Calculatr fr Percent Reductin in Outdr Water Use was then used t cmplete Steps, 2, 3, and 4. The calculatins are presented belw. As shwn, the reductin in utdr water use was 54%, which crrespnds t 6 pints in the SS 2.5 sectin, and 2 pints in the WE 2.3 sectin. Canada Green Building Cuncil -8- March 20, 2009
LEED Canada fr Hmes Calculatr fr Percent Reductin in Outdr Water Use: Example Legend User input cell Calculated cell Step : Calculate utdr water use fr baseline case Enter the ttal landscaped area, in square feet, and the reference evaptranspiratin rate, ET 0, in inches fr the mnth f July. Ttal Landscaped Area (sq ft):,000 ET 0 (in/m fr July) 8.7 Baseline Outdr Water Use (in/m) 5,394 Step 2a: Select apprpriate inputs fr each zne in the design case Chse apprpriate values fr species factr (KS), micrclimate factr (KMC), irrigatin efficiency (IE), and cntrl factr (CF): Divide landscaped area int landscape znes. Fr each zne, enter the descriptins, and use them t chse a value fr each factr. Please refer t the guidance dcument fr mre infrmatin abut hw t chse these values. Ntes: ) Well-designed landscaped areas have znes designed s that all plants within each zne will need the same amunt f water. 2) Many prjects will have fewer than 0 znes. Leave unused rws blank. Fr prjects with > 0 znes, please cntact yur Prvider. 3) Fr bxes with pull-dwn menus, chse frm the list. D nt type in infrmatin. 4) The fly-ut directins bx can be mved by dragging it. Canada Green Building Cuncil -9- March 20, 2009
Zne Descriptin f species K S Bushes, with typical water needs fr shrubs. Average K s fr Shrubs selected. 0.5 Descriptin f micrclimate Partial shade, nrmal winds. Ave K MC selected. K MC Type f irrigatin installed WaterSense pr? 3rd-party verif? # f WE 2. measures met? Rtrs Neither 3 0.70 IE Type f irrigatin cntrl and % water savings Flw-cntrl sensrs yield 5% water savings. CF 0.85 2 Native wildflwers, with little water needs fr flwers. Lw K s fr grundcver selected. 0.2 Same as fr zne Nne N/A N/A 0.65 Nne. Step 2b: Calculate the utdr water use fr each zne in the design case Enter the area fr each landscape zne in square feet. Zne Area f zne (sq ft) K S K MC IE CF Water demand (in/m) Water demand (% f ttal) 500 0.5 0.7 0.85 637 66 2 500 0.2 0.65 830 34 Ttal,000 Step 2c: Calculate the ttal utdr water use fr the design case This step is cmpleted autmatically. If the errr checker belw indicates an errr in the calculatin, r if the Ttal utdr water demand is 0, please review the inputs and assumptins abve. Errr check N errrs Ttal utdr water demand (in/m): 2467 Canada Green Building Cuncil -0- March 20, 2009
Step 3: Calculate the percentage reductin in water demand This step is cmpleted autmatically t calculate the reductin in water demand between the design case and baseline case. Reductin in water demand: 54% Step 4: Calculate LEED pints This step is cmpleted autmatically t calculate the number f pints awarded in SS 2.5, WE 2.3, and ID 3. SS 2.5 pints 6 WE 2.3 pints 2 ID 3 pints (fr exemplary perfrmance) 0 Landscape Prfessinal Sign-ff Prject Hme Address 602 Riverside Ave., Sacrament, CA I hereby declare and affirm t CAGBC that the abve calculatin describes the landscape and irrigatin system that is installed at the site. Printed Name Jane De Cmpany Green Landscapers, Inc. Credential Certified Landscaper by CA State License Bard Signature Jane M. De Date 0/7/2008 Canada Green Building Cuncil -- March 20, 2009
Example 2 A hme in Cllege Statin, TX has a 000 ft 2 frnt yard, and a 500 ft 2 backyard. The frnt yard is nrth-facing, and is shaded fr mst f the day. The back yard is suth-facing, and is in direct sunlight fr mst f the day. Winds are nrmal. The prject has decided t use native species fr mst landscaping. The frnt yard will have tw 5x5 areas: ne planted with a nn-native, rnamental fruit tree, the ther with a native ak tree that has typical water needs fr a tree. The remainder f the frnt yard will be planted with a mix f wildflwers and shrubs that are all drught-resistant: All will rarely require water beynd precipitatin. The backyard will be planted with this same mix. A drip system is installed fr the wildflwer / shrub mix in the back yard, and fr the landscape znes in the frnt yard that are planted with trees. The system was nt verified by a 3 rd party, and it was nt installed by a WaterSense prfessinal. It includes 2 f the 6 distributin measures. Because they are in shade, and have lw water needs fr their species, there is n irrigatin system fr the wildflwer / shrub mix in the frnt yard. Frm http://texaset.tamu.edu/pet.php, fr July in Cllege Statin, TX, ET 0 = 7. inches fr the mnth f July. The LEED Canada fr Hmes Calculatr fr Percent Reductin in Outdr Water Use was then used t cmplete Steps, 2, 3, and 4. The calculatins are presented belw. As shwn, the reductin in utdr water use was 70%, which crrespnds t 6 pints in the SS 2.5 sectin, 4 pints in the WE 2.3 sectin, and 2 pints in the ID 3 sectin. Canada Green Building Cuncil -2- March 20, 2009
LEED Canada fr Hmes Calculatr fr Percent Reductin in Outdr Water Use: Example 2 Legend User input cell Calculated cell Step : Calculate utdr water use fr baseline case Enter the ttal landscaped area, in square feet, and the reference evaptranspiratin rate, ET 0, in inches fr the mnth f July. Ttal Landscaped Area (sq ft):,500 ET 0 (in/m fr July) 7. Baseline Outdr Water Use (in/m) 6,603 Step 2a: Select apprpriate inputs fr each zne in the design case Chse apprpriate values fr species factr (KS), micrclimate factr (KMC), irrigatin efficiency (IE), and cntrl factr (CF): Divide landscaped area int landscape znes. Fr each zne, enter the descriptins, and use them t chse a value fr each factr. Please refer t the guidance dcument fr mre infrmatin abut hw t chse these values. Ntes: ) Well-designed landscaped areas have znes designed s that all plants within each zne will need the same amunt f water. 2) Many prjects will have fewer than 0 znes. Leave unused rws blank. Fr prjects with > 0 znes, please cntact yur Prvider. 3) Fr bxes with pull-dwn menus, chse frm the list. D nt type in infrmatin. 4) The fly-ut directins bx can be mved by dragging it. Canada Green Building Cuncil -3- March 20, 2009
Zne Descriptin f species K S Descriptin f micrclimate K MC Type f irrigatin installed WaterSense pr? 3rd-party verif? # f WE 2. measures met? IE Type f irrigatin cntrl and % water savings CF 2 Native, drught-resistant wildflwers & shrubs. Lw K s fr Grundcver & Shrubs. Same as Zne. 0.2 0.2 Nrth-facing and shaded. Lw value fr K MC selected. 0.8 Nne N/A N/A Suth-facing and usually in sun. High value fr K MC selected..2 Lw vl/ Pt surce/ Drip Neither 2 0.65 0.70 Nne. Nne. 3 Nn-native, rnamental fruit tree. Requires a lt f water. High K s value fr tree selected. 0.9 Same as Zne 0.8 Lw vl/ Pt surce/ Drip Neither 2 0.70 Nne. 4 Native ak tree, with typical water needs fr tree. Average K s fr Tree selected. 0.5 Same as Zne 0.8 Lw vl/ Pt surce/ Drip Neither 2 0.70 Nne. Step 2b: Calculate the utdr water use fr each zne in the design case Enter the area fr each landscape zne in square feet. Zne Area f zne (sq ft) K S K MC IE CF Water demand (in/m) Water demand (% f ttal) 950 0.2 0.8 0.65 029 53 2 500 0.2.2 0.7 755 38 3 25 0.9 0.8 0.7 3 6 4 25 0.5 0.8 0.7 63 3 Ttal,500 Step 2c: Calculate the ttal utdr water use fr the design case This step is cmpleted autmatically. If the errr checker belw indicates an errr in the calculatin, r if the Ttal utdr water demand is 0, please review the inputs and assumptins abve. Errr check N errrs Canada Green Building Cuncil -4- March 20, 2009
Ttal utdr water demand (in/m): 960 Step 3: Calculate the percentage reductin in water demand This step is cmpleted autmatically t calculate the reductin in water demand between the design case and baseline case. Reductin in water demand: 70% Step 4: Calculate LEED pints This step is cmpleted autmatically t calculate the number f pints awarded in SS 2.5, WE 2.3, and ID 3. SS 2.5 pints 6 WE 2.3 pints 4 ID 3 pints (fr exemplary perfrmance) 2 Landscape Prfessinal Sign-ff Prject Hme Address 642 N. Washingtn St., Cllege Statin, TX I hereby declare and affirm t CAGBC that the abve calculatin describes the landscape and irrigatin system that is installed at the site. Printed Name Bill Weed Cmpany Credential B.S., Landscape Architecture Great Lawn Alternatives, Inc. Signature William N. Weed Date 0/7/2008 Canada Green Building Cuncil -5- March 20, 2009