TRANSBAY TRANSIT CENTER

Jenny Henry, PWP Landscape Architecture

Claire Johnson, Atelier Ten Environmental Consultants

Paul Kephart, Rana Creek Ecological Consultants

Market Street

Transbay Transit Center Design Competition

Project Goals:

• an “urban catalyst”

• an “urban purifier”

Sustainable Design Guidelines:

• Site Design and Planning

• Water Management

SCOPE DOCUMENTS ROOF PROPOSAL(courtesy HOK)

DESIGN COMPETITION

Pelli Clarke Pelli Architects Team

Transbay Transit Center Rooftop

TRANSBAY TRANSIT CENTER ROOFTOP PARK

Park Design Aspirations:

Fully inhabitable public park for neighborhood residents and transit users:Open lawn areaBotanical plantingMain plaza with café and seatingChildren’s play areasAmphitheater and stage

Sustainable Aspirations:Decrease Impermeable (Roof) SurfaceDetain/Retain Stormwater Greywater Reuse for irrigation or park water featuresLow Water Demand Planting/Vegetation

AMPHITHEATERPICNIC

MEADOW PLAZAGROUNDCOVER

MOUND

PLAY GARDEN

PLAY GARDEN

GROUNDCOVERMOUND

WATER JET FOUNTAIN

GRAY WATER

TREATMENT ZONES

PATH AROUND

OVERLOOK

MAIN PATH

WETLAND GARDEN AT SUBSURFACE

GREYWATER TREATMENT AREA

OVERLOOK WETLAND GARDEN

PATH AROUND

OVERLOOK

Transbay Goals: WaterMinimum goal: Meet LEED credits for stormwater and water efficiency

Aspirational goal: Reduce use of potable water where non-potable water can be used.

Current status: On track to exceed minimum goal.

Water System Design

Water System Design

Water System Design

Water Benchmarking

Base Case Design Case Reduction[gallons per year] [gallons per year] [%]

Potable Water Use 21,179,000 8,224,000 62%Irrigation water use 3,389,000 1,694,000 50%Domestic water use 11,658,000 7,988,000 31%Cooling tower water use without geothermal - 594,000 -Cooling tower water use with geothermal - 237,800 -

Stormwater runoff to CSO 2,929,000 343,000 88%Sewage to CSO 17,790,000 8,288,000 53%Total volume to CSO 20,719,000 8,631,000 58%

annual water savings of 8,224,000 gallons =

100 typical U.S. houses

Water Use Summary

ScenarioAnnual Potable

Water Use

Annual Cost of Potable Water @ $5.40/100 cu. ft.

Annual Sewer Discharge

Annual Cost of Sewer Discharge

@ $9.66/cu. ft. Total Annual

CostTotal Annual Cost Savings

[gallons per year] [$ per year] [gallons per year] [$ per year] [$ per year] [$ per year]Design 1 21,179,215 $152,898 17,789,765 $268,451 $421,349 -

Design 2 11,3001,97 $81,579 9,557,762 $151,687 $233,266 $188,000

Design 3 10,943,565 $79,004 9,201,130 $147,066 $226,070 $195,000

Design 4 10,387,458 $74,990 8,645,023 $139,861 $214,850 $206,000

Design 5 8,224,329 $59,373 8,288,391 $111,834 $171,207 $250,000

Design Scenario 1 - LEED base caseDesign Scenario 2 - Water conserving fixtures, native vegetation and efficient irrigationDesign Scenario 3 - Hybrid geothermal systemDesign Scenario 4 - Graywater ReuseDesign Scenario 5 - Stormwater reuse—current tank size. Current scheme.

All water rates come from the San Francisco Public Utilities Commission website. Additional monthly fees not included in this summary are as follows: suspended solids discharge fee, oil/grease fee, chemical oxygen demand discharge fee and monthly service charge based on meter size.

Water Cost Savings

Transbay TerminalPerformance Indicators

• First living roof to utilize a constructed wetland for treating greywater– 900,000 gallons annually

• Integrated biological, plumbing, and mechanical systems– Stacking functions

• Reduces sewage/stormwater discharge to City system– 2.7m gallons annually

• Educational and interpretive value– 94,000 visitors daily

Transbay TerminalPolicy Achievements

• Overcoming ambiguous and outdated city/state policy– City: Ch. 16 (MOU for stormwater)– State: Appendix G, Title 24 (Commercial greywater)

• Stormwater MOU: PUC / Building Inspectors / Health Dept. – All 3 entities met and solidified stormwater standards– Can this happen for greywater?

• Variance Permit– Re-use of water to flush toilets - not currently part of code

• Precedent for future water re-use inside commercial buildings– Sets the standard– Scale and visibility of project

• What’s Needed:– No Water Quality Re-Use Standards currently exist– Comprehensive Greywater Re-Use Code in addition to landscape irrigation

Transbay TerminalReturn on Investment

• 25 year R.O.I. (conservative)• Up front costs of $1.2 - 1.6M• Saving $60K per year

Assumptions:• Potable water prices will increase

60% in 5 years– Used this 5th year price for

projections• Savings compared to an efficiently

designed system

Implications for Silicon Valley

Casa Feliz SAN JOSE

Return on Investment

• San Jose’s first Living Roof• LEED Gold certification• Avoided $300K Stormwater fee utilizing Living Roofs

Implications for Silicon Valley

• Cost savings for:– City of San Jose: Infrastructure & Energy– Developers: ROI, Avoiding Fees & Marketability

• Now is the time– Water prices increasing and availability decreasing– Outdated infrastructure requiring considerable investment in near future

• Adjust the mindset that sustainability has immediate pay-backs– Cost / Benefit ratios have leveled

• Benefits of decentralized systems vs. massive infrastructure and treatment upgrades

MORE INFORMATION

Transbay Joint Power Authority www.transbaycenter.org

PWP Landscape Architecture www.pwpla.com

Atelier Ten Environmental Design Consultants

www.atelierten.com

Rana Creek www.ranacreek.com

SF PUC Stormwater Design Guidelines www.sfwater.org

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