co-benefits of green infrastructure: an environmental and...

Onondaga County Executive Joanne M. Mahoney

www.savetherain.us

Co-Benefits of Green Infrastructure:An Environmental and Economic Analysis of

the Save the Rain ProgramZachary Monge, P.E.

CH2M Syracuse

NYSAWWA/NYWEA Joint Energy Conference November 16, 2016

Co-Authors:

Andrew Potts, P.E. – CH2M

Tom Rhoads, P.E. – Onondaga County Dept. of Water Environment Protection

Onondaga County Executive Joanne M. Mahoney www.savetherain.us

• 7,660 acres• 6.1 Billion Gallons Total Annual Combined Sewage Generated by the Metro Combined Sewer Service Area

City of Syracuse

Onondaga CreekHarbor Brook

Onondaga Lake

Onondaga County, New York

America’s First Green Infrastructure Consent Order


• 1988 – Atlantic States Legal Foundation files lawsuit against County

• 1998 – METRO consent judgment replaced with Amended Consent Judgment (ACJ)

• 2009 ACJ amended to authorize use of Gray and Green infrastructure

Onondaga Lake Facts

Watershed: 285 Square Miles

1 Mile Wide – 4.6 Miles Long

Average Depth: 35 feet

Max Depth: 63 feet

1940 – Swimming Banned

1970 – Fishing Banned

History


www.savetherain.us

• Developed System Model (SWMM)

• Separated and closed 12 CSOs

• Completed 1 storage facility(Erie Blvd)

• Constructed 4 Floatables ControlFacilities (HB, Franklin, Teall, Maltbie)

• Completed 2 Regional Treatment Facilities (Midland, Hiawatha)

• At least 35 projects investing over $350 million

1998-2008 CSO Abatement Accomplishments


• Agreed to by all parties (State, ASLF, County)

• Authorized use of Gray and Green infrastructure

• Requires Storage Facilities in place of RTFs

• Includes time extension for Construction, and Metro phosphorus effluent limit

• Balanced program provides additional water quality and community benefits– Improve Quality of Life (civic infrastructure investments),

Promote Sustainability (beyond stormwater), Cost Benefit/Efficiency

Fourth Stipulation to the ACJ (2009)


www.savetherain.us

• 185 projects throughout CSS• Compliments Gray Program• Total Gray + Green annual

volume wet weather capture requirements:

89.5% by Dec 201391.4% by 201593.0% by 201695.0% by Dec 2018

• Extensive monitoring & reporting required

Nicholas J. Pirro Convention Center66,000 sq.ft. Green Roof (Completed 2011)

Before/After

Green Infrastructure Program Summary 2009 - 2018


• US EPA Green Infrastructure Community Summit

• U.S. Water Prize• NYS Environmental

Excellence Award• APWA Environmental Project

of the Year (West Onondaga St.)• StormWater Solutions Magazine

Top Stormwater Project(Rosamond Gifford Zoo)

• American Academy of Environmental Engineers Honor Award (Water Street Gateway )

2013 US Water Prize CeremonyWashington DC

National and Regional Recognition


185 projects completed and120,000,000+ gallons of runoff reduction

Save the Rain Project Map


Net Environmental Benefit Analysis (NEBA)

• Publicly available document• Appendix to County’s 2015 Annual

Report:– http://savetherain.us/annual-report-

2015/

http://savetherain.us/annual-report-2015/


Net Environmental Benefit Analysis (NEBA)

• Comprehensive review of 169 constructed Save the Rain projects through 2014– Projects grouped into two categories

• Structural – Providing benefits through infiltration and/or storage• Trees – Including 4 shrubs = 1 tree

– “Easily” Quantifiable Benefits• Water quantity, water quality, energy, air quality, climate change, etc.

– “Not Easily” Quantifiable Benefits• Green job creation, crime reduction, increased property values,

enhanced climate change resiliency, etc. • Significant empirical research required


Tools and Methods• Tree Benefits

– i-Tree (version 6.09), USDA Forest Service• i-Tree Hydro – Measures effects in tree cover changes in a defined

watershed for water quantity and quality benefits • i-Tree Eco – Measures effects of urban forest tree inventory for air

quality benefits

• SWMM– County’s combined sewer system model is basis for ACJ compliance

• Used to determine stormwater capture and CSO reduction benefit for individual GI projects

• US EPA BenMAP– Used for air quality benefit calculations


Tools and Methods

• Monetary Benefits– Reported in 2014 dollars– 40 year return period, 3% discount rate– Calculation method varies per benefit based on readily

available data– Per capita population assumed to remain constant


Assumptions• Younger trees provide less benefit than older trees• All benefits based on local climate data available for SYR, NY• 3% tree mortality rate (~40 year lifespan) • GI projects are regularly maintained and operated• GI projects are replaced at end of service life (i.e. porous

pavements)


Trees Planted through 2016• Excludes County Street Tree Program• Tree size determined by comparing to USDA Forest

Service database


Water Quantity Benefits

• Reduced stormwater/CSO volume (SWMM)– 109.7 MG stormwater, 53.4 MG CSO

• Reduced wastewater treatment volume– Of 109.7 MG removed by GI, 92.4 MG removed from

sewer through infiltration/evaporation– Reduced WW treatment (39.0 MG) = stormwater

removed – CSO reduction


Water Quantity Benefits

• Reduce Potable Water Usage– Cistern projects (Zoo and War Memorial) and rain barrels– Assumed 60% of rain barrels are maintained and operated properly

and EPA estimate of 1,300 gallons stormwater saved per year– Cisterns based on measured savings before/after projects– Total savings = 13.5 MG/yr


Water Quality Benefits

• Pollutant load reductions– BOD5, TSS, TP, TN, FC– Selected the lesser of measured values from Onondaga County CSO and US EPA average

concentrations – Pollutant reduction = CSO reduction volume x pollutant concentration

• BOD5 = 13,000 lb/yr• TSS = 37,100 lb/yr• TP = 200 lb/yr• TN = 1,600 lb/yr• FC = 7,600 x 1012 lb/yr


Air Quality/Climate Change Benefits • i-Tree Eco calculates air pollutant removals from trees

• Reduce emissions from reduced wastewater treatment and building heating/cooling calculated based on EPA metrics


Air Quality/Climate Change Benefits • Climate change benefits (CO2)

– Tree sequestration calculated by i-Tree Eco metrics for CO2 for small, medium and large trees• 0.030, 0.034, 0.58 (lb/m2/yr)

• CO2 sequestration from plant biomass (green roofs, bioretention) = 0.37 lb/m2/yr (MSU, Andresen, 2009)

• Avoided emissions from WW treatment (0.5 lb/kWh electric, 0.14 lb/therm natural gas, US EPA metrics)


Valuation – Annual Savings• Wastewater treatment cost savings = $89,700

– Average cost to treat gallon of WW at County Metro WWTP = $2.30/1,000 gal

• Potable water savings (billed cost) = $33,500– Average City of Syracuse billing rate = $2.50/1,000 gal

• Equivalent avoided gray infrastructure costs = $35M (one time cost)– Without green projects, additional gray projects required– Average cost for completed gray projects = $0.66/gal CSO

reduction


Valuation – Annual Savings• Savings from reduced electrical usage from tree cooling

benefits = $400– $0.117/kWh, National Grid 2014 rate

• Savings from reduced natural gas usage = $2,130– $0.71/therm, National Grid 2014 rate

• Air quality savings = $4,530– Based on US EPA BenMAP metrics for air pollutant removal in

relation to human health• Climate Change Savings = $54,745

– Interagency Working Group estimate of $0.043/lb CO2 removed


Summary – Annual Benefits


Summary• Total Economic Savings = $220,000/yr, $8 million after 40 years• Equivalent avoided gray infrastructure cost = $35 million

– Gray infrastructure also does not provide the economic, environmental, and social benefits provided by green infrastructure

• Improved water quality of Onondaga Lake and its tributaries has spawned development and investment

– Lakeview Amphitheater – Onondaga Creekwalk– Onondaga Lake Loop the Lake Trail– Investment in Armory Square and Inner Harbor


Additional Benefits for Future Consideration• Reduced salting demand for porous pavements

– Studies have shown 75% reduction

• Enhanced potential for green job opportunities over life of projects• Enhanced recreation opportunities • Crime reduction• Enhanced property values• Increased air emissions due to construction vehicles (negative benefit)• Economic, social, and environmental benefits related to reduction in peak

storm flows • Derivation of a more detailed analysis for groundwater recharge


Contributors• SUNY ESF

– Ted Endreny, Tom Taggart, Chuck Knoll• US Forest Service

– David Nowak, Alison Bodine, Alexis Ellis


www.savetherain.us

Thank You

Zachary Monge, P.E.

Project Manager

CH2M Syracuse

[email protected]

315-401-7109

mailto:[email protected]

co-benefits of green infrastructure: an environmental and...

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