Stanford Green Dorm Project: Exterior Water System

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


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


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




• Green Roof




The Green RoofThe Green Roof

Benefits• Runoff

Reduction• Runoff Quality• Insulation• Energy Savings• Noise Reduction• Heat Island

Effect• Beautification


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


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


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.


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.


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


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


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


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.


Preliminary Preliminary DesignDesign

Two main components:Two main components:•Extensive (modules)Extensive (modules)•Intensive (continuous)Intensive (continuous)

Intensive

Plan View Elevation

Extensive

Plan View


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?


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)


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


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.


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.)


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.)


Green Roof Element DesignGreen Roof Element DesignModules

Water Outlet

Continuous

Gutter


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.


ConsiderationsConsiderations

• Taking into account other rooftop technologiesTaking into account other rooftop technologies

• Solar PanelsSolar Panels• Night Sky Water CoolingNight Sky Water Cooling


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


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


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




• Green Roof





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


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


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


Transport ChannelsTransport Channels Gutters Gutters DownspoutsDownspouts

Contaminant RemovalContaminant Removal Leaf ScreensLeaf Screens Roof WashersRoof Washers

Rainwater HarvestingHarvestingTransportTransport


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


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


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


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


Figure from Rinker Materials, http://www.rinkermaterials.com/stormceptor

Bypass ChamberBypass Chamber

Treatment Treatment ChamberChamber

InflowInflow

OutflowOutflow

Rainwater HarvestingRainwater HarvestingMinimizing Stormwater RunoffMinimizing Stormwater Runoff


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


IrrigationIrrigationAlternative SourcesAlternative Sources

In addition to municipal supplies:In addition to municipal supplies:

Gray WaterGray Water

RainwaterRainwater


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


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


IrrigationIrrigationSupported AreaSupported Area


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




• Green Roof





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


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


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


Questions ? Questions ?

Documents

Stanford Green Dorm Project: Exterior Water System