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Sulekha Gangopadhyay

Capstone Final

Fall 2017

Rehabilitation of New York City’s Newtown Creek through

Green Infrastructure Expansion in Maspeth

Part I: Introduction

Tracking sources of waste and environmental pollution in contaminated urban waterways

and achieving environmental rehabilitation is a complex and challenging process involving

multiple strategies and forms of data collection. The New York City waterway, Newtown Creek,

is designated as a Superfund site. The cleanup of Newtown Creek is slowly underway through

multi-stakeholder processes and collection and examination of soil and water quality data.

Contaminants include industrial waste, raw sewage, oil, and street trash1. In 2010, Exxon Mobil

settled a suit filed by the state of New York with $25 million towards the cleanup of Newtown

Creek.2

In older cities like New York, water from storm events exceeds sewer system capacity,

and due to combined stormwater and sewage systems, discharges untreated into city waterways.

The lack of permeable surface areas commonly found in urban areas also contributes to runoff.

Fecal matter can be found in the Creek when it rains, due to New York City’s combined overflow

sewage system, which opens out into more than 400 locations along the coasts of New York City

boroughs. New York City is currently in non-attainment of the Federal Clean Water Act, in

large part due to CSO related pollution in city waterways, an estimated 27 billion gallons per

1 Enman, S. (2017). Newtown Creek: How to fix the combined sewage overflow problem. The Brooklyn Eagle. 2 Navarro, M. (2010). Exxon Mobil Settles State Suit on Newtown Creek Cleanup. New York Times. Retrieved from:

http://www.nytimes.com/2010/11/18/nyregion/18newtown.html?mcubz=0

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year3. Moving forward, climate change and accompanying extreme weather events will

increasingly pose challenges for combined sewer outflow mitigation, due to increased

precipitation.

One of the organizations working on water quality in the creek is Newtown Creek

Alliance (NCA), a very small local community organization with a two-person staff and a board

of directors. The focus of the organization according to the website is habitat restoration, water

quality, and restoring public access through green infrastructure, bioremediation, and brownfield

redevelopment planning4.

Other NCA public engagement projects and activities include street-end cleanups, tours,

and wildlife education. Water quality issues in the creek include combined sewer overflow

(CSO) problems, the Greenpoint oil spill, hazardous industrial dumping from past and present,

and the high density of waste transfer stations in the surrounding region. Current efforts include

reviewing water quality data and soil samplings, the mussel filtration project and determining

upstream waste sources. Newtown Creek Alliance is also investigating the green infrastructure

potential for rooftop areas around Newtown Creek for diversion of stormwater from CSO, which

serves as the focus of this report.

Green infrastructure is a major area of interest for Newtown Creek Alliance, particular

industrial green roofs, due to the zoning in the regions surrounding Newtown Creek. NCA

previously partnered with several other organizations to build the Kingsland Wildflowers green

roof in Greenpoint, which is a 20,000-foot green roof on an industrial building that serves to

retain stormwater, provide habitat for bees and bird populations, and provide a space for

3 NYC DEC (2008). Wastewater Infrastructure Needs of New York State. Retrieved from: www.dec.ny.gov/docs/water_pdf/infrastructurerpt.pdf 4 Newtown Creek Alliance (2017) Retrieved from: www.newtowncreekalliance.org

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educational and cultural activities. In 2013, NCA worked with a property owner on Sutton Street

in North Brooklyn to build a green roof on an industrial building.

Methodology:

The green infrastructure recommendations and green roof stormwater retention/diversion

calculations in this report involved compiling city and state agency data, maps, and policy

reports pertaining to New York City Superfund waterways and CSO mitigation, and also

analyzing urban stormwater management literature.

Part II: Project Scope

Green infrastructure - rain gardens, bioswales, green roofs, porous streets and sidewalks,

etc. - may be utilized to mitigate combined sewer outflow. Green roofs can improve water

quality by filtering out heavy metals and excess nutrients from stormwater5. One possible

strategy for mitigating sewage overflow into the creek is to expand green roof space near

Newtown Creek, in order to increase capacity to absorb excess storm water and divert it from the

sewage outfalls. Green roof capacity for absorption and diversion depends on several factors,

including connection to outfalls, roof load bearing capacity, cost, and available financing

mechanisms. As much of the area adjacent to Newtown Creek is served by direct drainage and

not combined sewer infrastructure, the rooftops selected for the purpose of this proposal are

within the combined sewer outfall sewershed areas. Other co-benefits of green roofs include

insulation, energy savings, increasing species habitat, reducing smog, and providing relief from

urban heat island effect.

5 NYC Parks (2013). Green Roofs. Retrieved from: https://www.nycgovparks.org/pagefiles/53/Citywide-Services-Green-Roof_2.pdf

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The feasibility assessment for this project involves total capacity calculations for

proposed implementation of expanded square footage of green rooftop surface area for the

diversion of storm water from CSO via green infrastructure (green roofs) in the Newtown Creek

sewer shed area. According to the NYC DEP Long Term Control plan document for Newtown

Creek, 83 million gallons per year of CSO reduction total are anticipated as a result of current

and planned projects identified in the LTCP document6. However, outfall NC-077 alone, one of

the top three in terms of discharge volume, has an outflow of 300 million gallons per year,

according to the NYC DEP Long Term Control Plan7. The LTCP proposes options for gray

infrastructure, tired by cost and percentage diversion, which remain to be determined. Newtown

Creek Alliance is proposing expanding green infrastructure into areas identified as points of

inadequate mitigation in order to supplement the NYC DEP Long Term Control Plan. Next steps

are utilizing existing data and maps identifying adjacent CSO drainage sheds and prospective

rooftop locations for green roofs, as well as calculating the added mitigation quantity of the total

area and attendant costs.

The focus of this project is expanding green infrastructure in the form of industrial green

roofs in the Maspeth area, to the east of Newtown Creek. Combined sewer outfall NC-077 has

the largest volume of outflow in the creek, at roughly 300 million gallons per year according to

NYC DEP Long Term Control Plan data. Parties interested and/or potentially involved include

rooftop owners in the CSO sheds surrounding the creek, Newtown Creek Alliance, Riverkeeper,

DEP, and DEC.

6 NYC DEP (2017). Newtown Creek CSO Long Term Control Plan. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml 7 NYC DEP. (2017). Newtown Creek CSO Long Term Control Plan. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml

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New York City Sewage Drainage Typology

NYC DEP (2017). NYC Sewer Systems. Retrieved from:

http://www.nyc.gov/html/dep/pdf/green_infrastructure/sewer_drainage_area_types_map.pdf

As the figure above shows, much of the area immediately adjacent to Newtown Creek is

connected to direct drainage and not combined sewer outfalls. The area chosen for the purpose of

this proposal for green rooftops in Maspeth fall within sewersheds connected to combined sewer

outfalls.

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Newtown Creek CSO Outfall Map

NYC DEP (2017). Newtown Creek CSO Long Term Control Plan. Figure ES-1. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml

Newtown Creek is the site of numerous combined sewer outfalls, including outfall NCQ-077

near the Maspeth area, depicted here.

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Green Infrastructure Projects in the Newtown Creek Area

NYC DEP (2017). Newtown Creek CSO Long Term Control Plan. Figure ES-3. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml

The NYC DEP Long Term Control Plan document for Newtown Creek includes the

following map of green infrastructure planned, under construction, or already completed in the

areas surrounding Newtown Creek. The map shows several points in yellow for GI in

construction near Maspeth.

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Newtown Creek Outfall NCQ-077 and Corresponding Sewershed

Open Sewer Atlas (2017) Wet Weather Map. Retrieved from: http://openseweratlas.tumblr.com/wetweathermap

The rooftop areas selected in Maspeth outside the direct drainage and separate sewage

system areas immediately adjacent to the creek are part of the CSO shed that corresponds with

outfall NCQ-0778, which is of particular concern.

8 Open Sewer Atlas (2017) Wet Weather Map. Retrieved from: http://openseweratlas.tumblr.com/wetweathermap

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Potential Industrial Green Roof Areas – Maspeth Region

Left: Newtown Creek Alliance (2017) IBZ/NYCDEP Priority Area Overlap: Lots and Buildings. Retrieved from:

http://newtowncreekalliance.org/green-roofs

Right: Enlarged GIS figure of Maspeth lot areas containing rooftops identified via NYC MapPLUTO

The total building area in the selection is roughly 5,893,077 square feet9, located between

Metropolitan Avenue to the south and Queens Midtown Expressway to the north. Most of the

buildings in the selection are private and industrial, with some public buildings (NYC DOT).

Buildings in the selection are primarily categorized as M1-1/M2-1/M3-1 zoning.

9 NYC Dept. of Planning (2017). NYC MapPLUTO. Retrieved from: https://www1.nyc.gov/site/planning/data-maps/open-data.page

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Buildings in the Selection Area - 10,000 square feet and up

NYC Dept. of Planning (2017). NYC MapPLUTO. Retrieved from: https://www1.nyc.gov/site/planning/data-maps/open-data.page

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NYC Dept. of Planning (2017). NYC MapPLUTO. Retrieved from: https://www1.nyc.gov/site/planning/data-maps/open-data.page

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Aerial Maps

[Google Maps]

As shown here, the buildings in the Maspeth selection are primarily industrial and the rooftops

overall are flat, ideal for rainwater capture.

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Data and Calculations:

Successful green roof implementation involves estimating appropriate soil depth for roof

load bearing capacity, as well as planning for average and predicted rainfall, in order to

determine adequate soil depth for appropriate storm water capture quantities. Climate models

indicate that annual average precipitation in New York State will increase by 1-8% by 2020, and

the number of heavy rainfall events will increase as well. The number of days of over 1 inch of

rainfall in New York City is expected to be roughly 13, and roughly 3 for days over 2 inches of

rainfall in the 2020s10.

1. Stormwater volume produced by rain event: A 2” rain event across 10,000 square foot

of roof space would amount to a total stormwater volume of 1,667 cubic feet or 12,470

gallons (1/6 of a foot of rain multiplied by 10,000 feet of area = 1,667 cubic feet).

2. Stormwater volume absorption of soil: 1 cubic foot of lightweight green roof medium

could potentially hold 0.33 cubic feet or 2.4 gallons of water (Professor Paul

Mankiewicz, personal communication, December 2017); therefore, 10,000 square feet of

medium at this thickness could capture 24,000 gallons of stormwater. Therefore, 12” of

soil medium can handle up to an almost 4" storm. 6 inches of this medium is adequate for

approximately a 2” rain event.

3. Outfall volume: According to the NYC DEP Long Term Control Plan, CSO outfall NC-

077 in the Maspeth section of Newtown Creek has a discharge volume of 300 million

10 Horton, R., D. Bader, C. Rosenzweig, A. DeGaetano, and W. Solecki. 2014. Climate Change in New York State: Updating the 2011 ClimAID

Climate Risk Information. New York State Energy Research and Development Authority (NYSERDA), Albany, New York.

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gallons per year, and roughly 41 discharges per year, accounting for 25.8% of CSO

discharge into the Creek. The volume of discharge through NC-77 is second to outfalls

NC-083 and NC-01511.

4. Rooftop diversion potential: The total amount of roof space in Maspeth is estimated

here through NYC MapPLUTO data to be about 5,893,077 square feet12. A two-inch rain

event would produce about 982,180 gallons (1/6 foot of rain multiplied by 2,893,077

square feet) of water total across this area, which would then be easily accommodated by

6” of the growing medium and diverted from the combined sewer outfall. However, an

additional consideration is space limitations on some roofs due to other uses. The average

discharge volume per event for NC-77 is roughly 7,317,073 million gallons. Industrial

green roof implementation across the selected rooftops in Maspeth could divert 13.4% of

this average volume. However, Newtown Creek Alliance plans to refine the focus further,

and select properties with rooftop space over 10,000 square feet as best candidates for

green roof implementation.

11 NYC DEP. (2017). Newtown Creek CSO Long Term Control Plan. Retrieved from: http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml 12 NYC Dept. of Planning (2017). NYC MapPLUTO. Retrieved from: https://www1.nyc.gov/site/planning/data-maps/open-data.page

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Case Studies:

Green roofs have been implemented for the purpose of storm water retention in older

cities with combined sewer systems in New York City and other cities, including Philadelphia,

Chicago, and Brussels. According to a scholarly study of green roof storm-water retention

capacity in Brussels, “Roof greening on just 10% of the buildings would already result in a

runoff reduction of 2.7% for the region and of 54% for the individual buildings.” (Mentens, J.

2006). In a study of a prototype green roof implemented in Pittsburgh, Pennsylvania, the authors

concluded, “The green roof also reduced the flow rate of runoff throughout storms. Peak values

from the green roof were between 5% and 70% lower than control roof flow rates” (Bliss, D.

2009).

An existing industrial green roof in the Newtown Creek sewershed area is Kingsland

Wildflowers, which absorbs storm-water, provides habitat for native flora and fauna, and

provides a venue for educational and community events. Kingsland Wildflowers was funded by

the Greenpoint Community Environmental Fund, which allots money to environmental projects

through funds from the legal settlement by ExxonMobil. GCEF is run by the NYS Department of

Environmental Conservation and the NYS Attorney General13. Newtown Creek Alliance has also

worked in partnership to establish the Sutton Street green roof project. The city of Philadelphia

has implemented extensive green infrastructure for storm water retention and CSO mitigation.

Newtown Creek Alliance is proposing expanding green roof area in the CSO shed areas

surrounding Newtown Creek, and for the scope of this report, Maspeth in particular, primarily

for stormwater retention and diversion from combined sewer overflow.

13 Greenpoint Community Environmental Fund (2015). Retrieved from: http://gcefund.org/

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Funding:

Currently, the primary incentives for green roof implementation on private rooftops are

the DEP green infrastructure grant, and green roof tax abatement through NYC Buildings;

currently the credit amounts to roughly $5.23 per square foot14. However, these have not been

particularly successful incentives. However, there are other co-benefits to implementing green

roofs that private building owners cab consider, including extending the life of the building roof

through reduced exposure to UV and weather related damage, as well as increased energy

efficiency through mitigation of urban heat island effect. Through the process of

evapotranspiration by vegetation, green roofs provide insulation and cooling benefits, and

decrease air conditioning costs, of increasing concern due to rising global average temperatures

and energy costs. Green roofs also serve to mitigate urban heat island effect15.

Current incentive programs for private green roof installation have produced limited

results. Another possible strategy for incentivizing green roof installation is adoption of a similar

approach to the city of Philadelphia, in which a stormwater fee has been implemented16. Such a

fee could be based on the amount of stormwater created on the property. Another strategy is

requiring stormwater retention considerations for new construction in the city to ensure no

further burden on the current stormwater infrastructure. The green roof grant functions through

14 Newtown Creek Alliance (2017) Green Roof Tax Abatement. Retrieved from: http://www.newtowncreekalliance.org/green-roofs/

15 Mankiewicz, P. (2009). Green Roofs and Local Temperature. Living Architecture Monitor. Volume 11, No. 1.

16 Philadelphia Water Department. (2017). Stormwater. Retrieved from http://www.phila.gov/water/wu/stormwater/pages/default.aspx

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reimbursement, which can be discouraging and for roof owners to take on. Therefore,

restructuring the green roof grant process may help to incentivize building owners17.

Mankiewics, P, Spartos, P., Dalski, E. (2009). Green Roofs and Local Temperature. Living Architecture Monitor. Vol 11, No. 1. pp 20-25.

Newtown Creek Alliance (2017) Green Roof Tax Abatement. Retrieved from: http://www.newtowncreekalliance.org/green-roofs/

17 Valderrama, A., Lochner, J., Koval, M. (2017). Catalyzing Green Infrastructure on Private Property: Recommendations for a Green, Equitable, and Sustainable New York City. NRDC. Retrieved from https://www.nrdc.org/sites/default/files/green-infrastructure-

recommendations-at-a-glance.pdf

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Conclusion and Recommendations:

Expanding green infrastructure by implementing green roofs in the Maspeth, Queens area

could create a substantial reduction in combined sewer overflow into Newtown Creek from the

Maspeth sewershed. This reduction can substantially supplement the amount of green

infrastructure related diversion planned by NYC DEP, as the DEP Long Term Control Plan for

Newtown Creek estimates only an 83 million gallons per year diversion from the Creek via local

green infrastructure by 2030, which is very minimal when considering outfall NC-77 alone in

Maspeth along the Creek has an outflow of 300 million gallons per year18.

Strategies to achieve greater stormwater diversion include:

- Increasing outreach in order to facilitate greater public understanding and participation in

industrial green roof implementation projects along Newtown Creek

- Restructuring the Green Infrastructure Grant program in order to incentivize property

owners, as the current reimbursement method poses difficulties for property owners

- Implementation of a stormwater fee based on level of runoff created by impermeable

surfaces on individual properties, and refining standards for new construction.

18 NYC DEP. (2017). Newtown Creek CSO Long Term Control Plan. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml

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Sources:

City of New York. (2017). NYC Open Data. Retrieved from: https://opendata.cityofnewyork.us

Daniel J. Bliss, Ronald D. Neufeld, and Robert J. Ries. Stormwater Runoff Mitigation Using a Green Roof. Environmental Engineering Science. February 2009, 26(2): 407-418. https://doi.org/10.1089/ees.2007.0186.

Enman, S. (2017). Newtown Creek: How to fix the combined sewage overflow problem. The Brooklyn Eagle.

EPA. (2017). Superfund Site: Newtown Creek. Retrieved from: https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0206282

Greenpoint Community Environmental Fund (2015). Retrieved from: http://gcefund.org/

Horton, R., D. Bader, C. Rosenzweig, A. DeGaetano, and W.Solecki. 2014. Climate Change in New York State: Updating the 2011 ClimAID Climate Risk Information. New York State Energy Research and Development Authority (NYSERDA), Albany, New York.

Mankiewics, P, Spartos, P., Dalski, E. (2009). Green Roofs and Local Temperature. Living Architecture Monitor. Vol 11, No. 1. pp 20-25.

Mentens, J, Raes D., Hermy, M. (2006) “Green roofs as a tool for solving the rainwater runoff problem in the urbanized 21st century?”

Landscape and Urban Planning. Volume 77, Issue 3.

Navarro, M. (2010). Exxon Mobil Settles State Suit on Newtown Creek Cleanup. New York Times. Retrieved from:

http://www.nytimes.com/2010/11/18/nyregion/18newtown.html?mcubz=0

New York DEC. (2017). Retrieved from: www.dec.ny.gov

NYC DEP. (2017). Newtown Creek CSO Long Term Control Plan. Retrieved from:

http://www.nyc.gov/html/dep/html/cso_long_term_control_plan/newtown_creek_ltcp.shtml

Newtown Creek Alliance (2017) Retrieved from: www.newtowncreekalliance.org

NYC Oasis. Retrieved from: http://www.oasisnyc.net/map.aspx

NYC Solar Map. Retrieved from: https://www.nysolarmap.com/

NYC Dept. of Buildings. (2017). Retrieved from: https://www1.nyc.gov/site/buildings/business/green-roofs.page

NYC DEC. (2017). Stormwater. Retrieved from: http://www.dec.ny.gov/chemical/8468.html

NYC DEC (2008). Wastewater Infrastructure Needs of New York State. Retrieved from: www.dec.ny.gov/docs/water_pdf/infrastructurerpt.pdf

NYC Dept. of Planning (2017). North Brooklyn Industry Plan. Retrieved from: https://www1.nyc.gov/site/planning/plans/north-brooklyn-vision-

plan/north-brooklyn-vision-plan-updates.page

NYC Dept. of Planning (2017). NYC MapPLUTO. Retrieved from: https://www1.nyc.gov/site/planning/data-maps/open-data.page

NYC Parks (2013). Green Roofs. Retrieved from: https://www.nycgovparks.org/pagefiles/53/Citywide-Services-Green-Roof_2.pdf

Northeast Regional Climate Center. (2017). Cornell. Retrieved from: http://www.nrcc.cornell.edu/

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Smith, P. (2013) The Toxins Lurking in Newtown Creek. New York Magazine. Retrieved from: http://nymag.com/news/intelligencer/newtown-

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Stein, J. and Kuz, Z. (2016). Fluid Frontiers: Stormwater management research in the Red Hook Sewershed, Brooklyn. Pratt Institute.

Valderrama, A., Lochner, J., Koval, M. (2017). Catalyzing Green Infrastructure on Private Property: Recommendations for a Green, Equitable, and Sustainable New York City. NRDC. Retrieved from https://www.nrdc.org/sites/default/files/green-infrastructure-recommendations-at-a-

glance.pdf

Wilson, W. (2016). Stormwater. University of Chicago Press.