L.E.P. AssociatesL.E.P. Associates
Lee TraynhamLee Traynham
Erin GardnerErin Gardner
Pascal MuesPascal Mues
Stanford Green Dorm Project: Stanford Green Dorm Project: Exterior Water SystemExterior Water System
June 7, 2005June 7, 2005
• Project Overview
• Green Roof
• Rainwater Harvesting System
• Irrigation System
• Research and Education
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Project OverviewProject Overview
GoalsGoals 50% reduction in wastewater flow50% reduction in wastewater flow
• stormwater vs household wastewaterstormwater vs household wastewater zero net use of lake water for irrigationzero net use of lake water for irrigation potential for expansionpotential for expansion
• flexibility for future modificationflexibility for future modification• greywater irrigation systemgreywater irrigation system
Research and EducationResearch and Education
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Major SystemsMajor Systems Green RoofGreen Roof
reduction of stormwaterreduction of stormwater Rainwater HarvestingRainwater Harvesting
reduced/zero net irrigation water usereduced/zero net irrigation water use expansion potential (potable)expansion potential (potable)
Irrigation SystemIrrigation System reduced net irrigation water usereduced net irrigation water use
All: MonitoringAll: Monitoring research and educationresearch and education
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Design EmphasisDesign Emphasis AdaptabilityAdaptability
enable later fundamental changes to systemenable later fundamental changes to system SustainabilitySustainability
conserve water, water quality, and resourcesconserve water, water quality, and resources Research PotentialResearch Potential
plan for sub-unit monitoring and data collectionplan for sub-unit monitoring and data collection
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
• Project Overview
• Green Roof
• Rainwater Harvesting System
• Irrigation System
• Research and Education
The Green RoofThe Green Roof
Benefits• Runoff
Reduction• Runoff Quality• Insulation• Energy Savings• Noise Reduction• Heat Island
Effect• Beautification
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Preliminary Preliminary DesignDesign
Two main types:•Extensive (continuous or modules)•Intensive (continuous)
Intensive
Extensive
Modules
Continous
Total roof area is approx. 4,500 ft2
•About half (2,500 ft2) green roof area•Extensive Modules•Intensive Continous
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Extensive SectionExtensive Section
Modules for testing purposes- changeable Modules for testing purposes- changeable substrate/vegetationsubstrate/vegetation
One module per two student rooms for One module per two student rooms for testingtesting 2 rooms/module * 9 modules * 110 ft2 rooms/module * 9 modules * 110 ft22/ room = / room =
2000 ft2000 ft22
Intensive section = 800 ftIntensive section = 800 ft2 2 7 rooms7 rooms
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Intensive SectionIntensive Section
Structural ConcernsStructural Concerns Imposes an additional weight of between Imposes an additional weight of between
290 and 970 kg/m290 and 970 kg/m2 2 (59-199 lb/ft(59-199 lb/ft22).). Typical intensive roof requires irrigation.Typical intensive roof requires irrigation.
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Researching the Researching the Green RoofGreen Roof
•Substrate•Vegetation
•Easily variable with modules
•Semi-permanent with standard green roof design
•Roof Membrane•Underlayment
•Permanent in modules and standard
green roof.
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
SubstrateSubstrate• Lava and PumiceLava and Pumice
– LightweightLightweight– Can be difficult to obtainCan be difficult to obtain
• Light Expanded Clay Light Expanded Clay Granules (LECA)Granules (LECA)
– LightweightLightweight– Large pore spaceLarge pore space– Absorb waterAbsorb water
• Crushed clay brick or tilesCrushed clay brick or tiles– Stable, uniformStable, uniform– Possibly raise pH of Possibly raise pH of
substratesubstrate
Source: Dunnertt, Nigel, Noel Kingsbury, Planting Green Roofs and Living Walls
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
VegetationVegetation
OptionsOptions•Mixing types of vegetationMixing types of vegetation•Native plant speciesNative plant species•Established plant speciesEstablished plant species•Mixing with different Mixing with different substratessubstrates
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
California Native PlantsCalifornia Native PlantsArtemisia Californica“Trailing Sagebrush”»0-0.5 m»31-76 cm of rainfall
Brodiaea Pulchella“Wild Hyachinth”»0.1-0.4 m»41-93 cm of rainfall
Source: Las Pilitas Nursery, www.laspilitas.com, www.mynativeplants.com
Castilleja foliolosa“Woolly Indian Paintbrush”»0.1-1 m»30-80 cm of rainfall
Ceanothus gloriosus“Moutain Lilac”»0.1-1 m»50-140 cm of rainfall
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Standard VegetationStandard VegetationExtensive(0-10 cm)
Semi-extensive(10-20 cm)
Ixia (Iridacea)»20 cm»High drought tolerance»Frost-free climates
Koeleria (Poaceae)»20 cm»High drought tolerance»Poor free-draining soils
Aloe (Aloeacea)»30-60 cm»High drought tolerance»Frost-free climates
Jovibarba (Crassulaceae)»20 cm»High drought tolerance»Clump-forming perennial
Acinos (Lamiaceae)»15 cm»High drought tolerance»Creeping perennial
Source: Dunnertt, Nigel, Noel Kingsbury, Planting Green Roofs and Living Walls.
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Preliminary Preliminary DesignDesign
Two main components:Two main components:•Extensive (modules)Extensive (modules)•Intensive (continuous)Intensive (continuous)
Intensive
Plan View Elevation
Extensive
Plan View
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Estimating RunoffEstimating Runoff Storage Capacity depends on:Storage Capacity depends on:
SeasonSeason Substrate depthSubstrate depth Layers of roof used in constructionLayers of roof used in construction Physical properties of growing mediaPhysical properties of growing media Slope of roofSlope of roof Vegetation usedVegetation used Rainfall intensityRainfall intensity
How much will the green roof reduce runoff?How much will the green roof reduce runoff?
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
MethodMethod Mass Balance:Mass Balance:
Difference between precipitation (inflow) and Difference between precipitation (inflow) and evaporation (outflow) plus storage capacity of green evaporation (outflow) plus storage capacity of green roof to get runoff.roof to get runoff.
All data from California Irrigation Management All data from California Irrigation Management Information SystemInformation System
Off ice of Water Use Efficiency, California Department Off ice of Water Use Efficiency, California Department of Water Resourcesof Water Resources
wwwcimis.water.ca.gov/cimis/welcome.jspwwwcimis.water.ca.gov/cimis/welcome.jsp Used data from San Jose Station (July 1987 to Used data from San Jose Station (July 1987 to
August 2002)August 2002)
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Method (continued)Method (continued)1.1. Daily Precipitation Volume = Daily Precipitation Volume =
Precipitation x AreaPrecipitation x Area
1.1. Daily Evaporation Volume = Crop Daily Evaporation Volume = Crop Coefficient x Potential Coefficient x Potential Evapotranspiration x AreaEvapotranspiration x Area
1.1. Runoff = Daily Precipitation Volume Runoff = Daily Precipitation Volume - Daily Evaporation Volume- Daily Evaporation Volume
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
The Crop Coefficient (KThe Crop Coefficient (KCC))
0.800.58Olive
1.120.04Pistachio
0.250.25Sedum Acre
High KCLow KCSpecies
Source: “A Guide to Estimating Irrigation Water Needs of Landscape Plantings in California,” University of California Cooperative Extension, California Department of Water Resources, 14.
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Low PrecipitationLow Precipitation Water year 1988 (Oct. 1, 1988 to Sept. 30, Water year 1988 (Oct. 1, 1988 to Sept. 30,
1989)1989)
Low Rainfall Year Potential Green Roof Runoff Storage
0
2000
4000
6000
8000
10000
12000
10/1/8810/15/8810/29/8811/12/8811/26/8812/10/8812/24/881/7/89
1/21/892/4/89
2/18/893/4/89
3/18/894/1/89
4/15/894/29/895/13/895/27/896/10/896/24/897/8/89
7/22/898/5/89
8/19/899/2/89
9/16/899/30/89
Date
Storage (gal.)
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
High PrecipitationHigh Precipitation Water year 1997 (Oct. 1, 1997 to Sept. 30, Water year 1997 (Oct. 1, 1997 to Sept. 30,
1998)1998)
High Rainfall Year Potential Green Roof Runoff Storage
0
5000
10000
15000
20000
25000
30000
35000
40000
10/1/9710/15/9710/29/9711/12/9711/26/9712/10/9712/24/97
1/7/981/21/98
2/4/982/18/98
3/4/983/18/98
4/1/984/15/984/29/985/13/985/27/986/10/986/24/98
7/8/987/22/98
8/5/988/19/98
9/2/989/16/989/30/98
Date
Storage (gal.)
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Green Roof Element DesignGreen Roof Element DesignModules
Water Outlet
Continuous
Gutter
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Other Benefits…Other Benefits…• Reduces noise Reduces noise
pollution.pollution.
• Reduces the urban Reduces the urban heat island effect.heat island effect.
• Beautification of Beautification of area.area.
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
ConsiderationsConsiderations
• Taking into account other rooftop technologiesTaking into account other rooftop technologies
• Solar PanelsSolar Panels• Night Sky Water CoolingNight Sky Water Cooling
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Monitoring Performance Monitoring Performance RunoffRunoff
●Measure gutter flowsMeasure gutter flows●Storage tank level Storage tank level changes with rain changes with rain events/seasonevents/season●Monitor street storm Monitor street storm drain flowsdrain flows
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Monitoring: Stormwater ControlMonitoring: Stormwater Control Extensive Green Roof (modules)Extensive Green Roof (modules)
Individual outlets (discrete sampling)Individual outlets (discrete sampling) Gutter flows (flowrate data)Gutter flows (flowrate data)
Intensive Green RoofIntensive Green Roof Bulk and local monitoringBulk and local monitoring Flowrates (comparison with extensive)Flowrates (comparison with extensive)
Storage Tank levelStorage Tank level Street DrainsStreet Drains
Locating sensor for green dorm total outflowLocating sensor for green dorm total outflow
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Monitoring: Insulation EffectMonitoring: Insulation Effect Temperature sensorsTemperature sensors
Indoor ambient temperatureIndoor ambient temperature Outdoor ambient temperatureOutdoor ambient temperature Rooftop temperatureRooftop temperature Indoor ambient temperature of comparable row Indoor ambient temperature of comparable row
houseshouses
Sensor PlacementSensor Placement Edge effectsEdge effects Module sizingModule sizing
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Monitoring: Stormwater QualityMonitoring: Stormwater Quality
Extensive Green Roof (modules)Extensive Green Roof (modules) Individual outlets (discrete sampling)Individual outlets (discrete sampling) Selective plumbing to downspouts (reuse)Selective plumbing to downspouts (reuse)
Intensive Green RoofIntensive Green Roof Bulk samplingBulk sampling In-roof sensorsIn-roof sensors
City standardsCity standards Monitoring as a regulatory advantageMonitoring as a regulatory advantage
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
• Project Overview
• Green Roof
• Rainwater Harvesting System
• Irrigation System
• Research and Education
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater Harvesting
BenefitsBenefits No-Cost SupplyNo-Cost Supply Reduces Unnecessary Use of Reduces Unnecessary Use of
Potable SupplyPotable Supply High QualityHigh Quality Decrease in Stormwater Runoff Decrease in Stormwater Runoff
VolumeVolume
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingRoof AreaRoof Area
Safety Depends on Material Safety Depends on Material
Some Painted Roofs
Tile
Chemically Treated Wood
Clay
AsbestosSlate
AsphaltMetal
Not Recommended
Recommended
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingRoof AreaRoof Area
0.4 – 0.5Flat Roof with Gravel Layer
0.5Flat Roof Smooth Tiles
0.75 – 0.9Pitched Roof Tiles
Drainage CoefficientRoof Material Type
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Transport ChannelsTransport Channels Gutters Gutters DownspoutsDownspouts
Contaminant RemovalContaminant Removal Leaf ScreensLeaf Screens Roof WashersRoof Washers
Rainwater HarvestingHarvestingTransportTransport
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingDistributionDistribution
Typical System Typical System ComponentsComponents
• FilterFilter• Smoothing InletSmoothing Inlet• Submersible PumpSubmersible Pump• Suction FilterSuction Filter• Pressure/Switch Flow Pressure/Switch Flow
ControllerController• Solenoid ValveSolenoid Valve• Float SwitchFloat Switch• Type ‘A’ Air GapType ‘A’ Air Gap11.11. Overflow Trap Overflow Trap
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Expected Rainwater RunoffExpected Rainwater Runoff
Roof Area x Drainage Coefficient x Filter Efficiency x Roof Area x Drainage Coefficient x Filter Efficiency x
x Annual Runoffx Annual Runoff
2,250ft2,250ft22 x 0.75 x 0.85 x 368mm = 209m x 0.75 x 0.85 x 368mm = 209m22 x 0.75 x 0.85 x 0.368m = x 0.75 x 0.85 x 0.368m = 49.03m49.03m33
≈≈ 50,000 Liters50,000 Liters
Rainwater HarvestingRainwater HarvestingStorage TanksStorage Tanks
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingStorage TanksStorage Tanks
Plastic Storage (Polyethylene and Plastic Storage (Polyethylene and Fiberglass)Fiberglass)
Wide Variety of Shapes, Sizes, & ColorsWide Variety of Shapes, Sizes, & Colors Above and Below Ground DesignsAbove and Below Ground Designs Least ExpensiveLeast Expensive Light-weight Light-weight Degradable – Require CoatingDegradable – Require Coating
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingTreatmentTreatment
Nonpotable OnlyNonpotable Only
FiltrationFiltration– Sediment FilterSediment Filter– In-Line FiltersIn-Line Filters– Activated Carbon Activated Carbon
FilterFilter– Reverse OsmosisReverse Osmosis
PotablePotable
Filtration + DisinfectionFiltration + Disinfection– Ultraviolet LightUltraviolet Light– OzoneOzone– ChlorineChlorine
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Figure from Rinker Materials, http://www.rinkermaterials.com/stormceptor
Bypass ChamberBypass Chamber
Treatment Treatment ChamberChamber
InflowInflow
OutflowOutflow
Rainwater HarvestingRainwater HarvestingMinimizing Stormwater RunoffMinimizing Stormwater Runoff
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Rainwater HarvestingRainwater HarvestingMinimizing Stormwater RunoffMinimizing Stormwater Runoff
Underground Oil–Sediment Separator Tank Underground Oil–Sediment Separator Tank (OSS)(OSS)
Separates Oil, Grease, and Sediment from Separates Oil, Grease, and Sediment from Stormwater RunoffStormwater Runoff
Prevents Resuspension and/or Scouring of Prevents Resuspension and/or Scouring of Previously Collected PollutantsPreviously Collected Pollutants
Potential 80% Total Suspended Solids (TSS) Potential 80% Total Suspended Solids (TSS) and 90% Oil and Grease Removal Ratesand 90% Oil and Grease Removal Rates
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
IrrigationIrrigationAlternative SourcesAlternative Sources
In addition to municipal supplies:In addition to municipal supplies:
Gray WaterGray Water
RainwaterRainwater
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Supply Source Liters/yr
Gray Water Creation 340,000
Rainwater Harvest (Standard Roof) 50,000
Rainwater Harvest (Green Roof) 53,000
Drip Irrigation (a.k.a. Trickle, Micro-)Drip Irrigation (a.k.a. Trickle, Micro-) Applies Water Slowly and Directly to RootsApplies Water Slowly and Directly to Roots 80% Efficiency – Highest80% Efficiency – Highest
• Use 30-50% Less Water than SprinklersUse 30-50% Less Water than Sprinklers Necessary for Gray Water (Safety)Necessary for Gray Water (Safety) Recommended for Use On:Recommended for Use On:
• TreesTrees• ShrubsShrubs• FlowersFlowers
Irrigation Irrigation Distribution SystemsDistribution Systems
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
IrrigationIrrigationDistributionDistribution
Drip Irrigation ComponentsDrip Irrigation Components Polyvinylchloride (PVC) MainlinesPolyvinylchloride (PVC) Mainlines
• Polyethylene (PE) Distribution LinesPolyethylene (PE) Distribution Lines Emitters Emitters
• (0.5, 1, 2 gallons/min)(0.5, 1, 2 gallons/min)• 12 – 24 Inches Apart12 – 24 Inches Apart
Filter: 150 – 200 mesh screenFilter: 150 – 200 mesh screen• Gray Water and Green Roof PretreatmentGray Water and Green Roof Pretreatment
Pressure Regulator: 20psiPressure Regulator: 20psi
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
IrrigationIrrigationSupported AreaSupported Area
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Turf Grass
(cool)
Turf Grass
(warm) Trees Shrubs GrapesFruit Trees
Sugar Beet
Annual Demand (Liters/yr) 758 532 431 431 457 687 770
Area Supplied by Gray Water (m2) 450 642 792 792 748 497 443
Area Supplied by Roof Water (Standard) (m2) 65 92 114 114 107 71 64
Area Supplied by Roof Water (Green) (m2) 70 100 123 123 116 77 69
Monitoring: Quality for Use Monitoring: Quality for Use Rainfall dataRainfall data
Available waterAvailable water Collected quantityCollected quantity
Irrigation requirementsIrrigation requirements Flow rate and area irrigatedFlow rate and area irrigated Distribution system compatibilityDistribution system compatibility
Treatment to Potable standardsTreatment to Potable standards Optimization of treatment systemOptimization of treatment system Regulatory standardsRegulatory standards
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
• Project Overview
• Green Roof
• Rainwater Harvesting System
• Irrigation System
• Research and Education
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Research and EducationResearch and Education
Scientific researchScientific research Data generation (monitoring)Data generation (monitoring) Design variationDesign variation
Engineering researchEngineering research System testing (monitoring)System testing (monitoring) Component variationComponent variation
Educational activitiesEducational activities Accessibility of informationAccessibility of information
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Supporting Research Supporting Research
Provision for general data collectionProvision for general data collection Built-in monitoring infrastructureBuilt-in monitoring infrastructure Discrete sampling arrangementsDiscrete sampling arrangements
Provision for experimentation and testingProvision for experimentation and testing Rapid adjustmentRapid adjustment Systems supportSystems support
• Rooftop power taps, data busRooftop power taps, data bus• CatwalksCatwalks
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
Supporting EducationSupporting Education Visible ElementsVisible Elements
Green RoofGreen Roof Rainwater collection tankRainwater collection tank Greywater-irrigated landscaping (orchard)Greywater-irrigated landscaping (orchard)
AccessibilityAccessibility Rooftop catwalks (physical access)Rooftop catwalks (physical access) Zero-outside-water garden (intellectual Zero-outside-water garden (intellectual
access)access) Educating RegulatorsEducating Regulators
Monitoring / Permiting interactionsMonitoring / Permiting interactions
L.E.P. Associates Green Dorm Exterior Water System June 7, 2005
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