Coastal Green Infrastructure for Westchester CreekMarcel NegretM.S. Candidate In Urban Environmental Systems Management

Programs for Sustainable Planning and DevelopmentGraduate School of ArchitecturePratt Institute

Demonstration of Professional CompetencyMay 25, 2015

Advisors: Jaime Stein and Alec AppelbaumTechnical Advisor: Paul Mankiewicz, PhD

ACKNOWLEDGEMENTS

I am immensely grateful for being surrounded by such an amazing group of talented and inspirational people. Thanks all of you for helping bring this work to fruition.

First I wanted to thank my advisor Paul Mankiewicz for helping me understand our potential to utilize nature-based systems. May his scientific contributions continue to influence generations to come. I am immensely grateful to Jaime Stein, thanks to for encouraging me to make the best out of each opportunity. I wish her enthusiasm continues to inspire many more. I am grateful to my peers JJ, Gina and Korin for making this experience so awesome and motivating. I would also like to thank professors Ira Stern, Damon Chaky, Alec Appelbaum and Gelvin Stevenson for their valuable contributions to my academic experience. Thanks to the developers of Open Sewer Atlas, their understanding and visualization of the city’s sewer system provided invaluable insights to my WCCW planning tool. I am also thankful to the SUP team at Future Green Studio, their research practices enabled a robust data collection to this project.

Additionally I would like to thank my project clients: Mr. Kenneth Kearns District Manager of Bronx Community Board 10 and Ms. Dorothea Poggi founder of the East Bronx Coastal Working Group. I am fortunate for being able to engage with deeply motivated residents of the Bronx, representing both community and environmental interests of the area.

Finally, I am grateful to my parents, their love, support and life testimony are an immense driver to my own pursuit.

To my wife, I fell enormous gratitude for having her as a life partner. Her love and unreserved support is a blessing.

Nanos gigantum humeris insidentes

Thank you all.

TABLE OF CONTENTS

1. Background 41.1. Opening Statement 41.2. Introduction 51.3. Risks at Westchester Creek 62. Project Framework 82.1. Questions of Interest 82.2. Project Client 82.3. Scope of Work and Goals 82.4. First Hand Analysis and Physical Survey 92.5. Westchester Creek Comprehensive Water Planning Tool 93. Existing Conditions 123.1. Watershed – Waterbody overview 123.2. Waterfront Community 123.3. History of Westchester Creek Watershed 123.4. Tidal Wetlands 153.5. Ecological Community 153.6. Population, Land Use and Ownership 183.7. Shoreline Conditions 223.8. Topography and Bathymetry 224. Related Regulatory and Planning framework 244.1. Waterfront Revitalization Program 244.2. Coastal Green Infrastructure Research Plan for New York City 264.3. Waterbody Classification and Usages 264.4. Combined Sewer Overflow Consent order 274.5. Waterbody Watershed Facilities Plan 314.6. CSO Long Term Control Plan 314.7. Green Infrastructure Plan for stormwater management 324.8. Stormwater Outfalls and Direct Storm Runoff 334.9. Future Flood plains projections by NPCC 334.10. East Bronx Resiliency Planning 364.11. East Bronx Waterfront: NY Rising Community Reconstruction Program 365. Coastal Green Infrastructure 385.1. Definition and typologies of Coastal Green Infrastructure 385.2. Coastal Flood Mitigation 395.3. Pollutant Removal and Water Filtration Performance Variability 435.4. Case studies in the region and around the world 455.5. Scaling Coastal Green Infrastructure at Westchester Creek 475.6. Shallowing and dredged sediments usage for marshland creation 525.7. Coastal Green Infrastructure as a research factor for upcoming studies 526. Conclusion 54

7. References 55

8. List of Figures 57

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1. BACKGROUND

1.1. Opening StatementThe east Bronx waterfront plays a key role for the communities along Eastchester Bay and the upper portion of

the East River. The abundance of boat clubs, marinas and tidal wetlands are examples of those waterfront assets. However, important challenges need to be urgently addressed: degraded coastal ecosystems, poor water quality and increasing risk to coastal flooding as an overarching stress factor. Based on the environmental conditions of the area, natural based strategies offer promising opportunities to address such stressing issues. Coastal Green Infrastructure restores or emulates natural coastal conditions; while mitigating storm surge and wave action, reducing erosion, improving water quality and providing habitat for wildlife. Civic groups, waterfront communities and local government of the east Bronx envision a protected shoreline, having cleaner waterbodies and a healthier coastal ecosystem. They acknowledge that this will improve quality of life, allow for the existing social networks to evolve and ultimately strengthen their self-sufficiency. In this particular moment, it becomes crucial to explore opportunities for coastal green infrastructure aiming to maximize waterfront planning and water management efforts in the East Bronx.

Figure.1: Westcheter Creek. Photo by M. Negret

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1.2. IntroductionHistorical maps show how Westchester Creek watershed was once a complex system of creeks and tidal

wetlands. Westchester creek watershed covered over 3,600 acres of the east Bronx most of which was marshland. After centuries of urban development and interrupting the natural water cycle, Westchester Creek is now impaired or stressed for all water body usages: ranging from public bathing to recreation and even aquatic life. Furthermore, after developing floodplains into urban environments, many coastal communities in the area are facing increasing flood hazards from rising seas and extreme weather events, such as hurricanes and northeasters.

Over the last few decades and in more recent years, New Yorkers have started to value the long time neglected waterfront and acknowledge the importance of the city’s coastal areas. The Department of City Planning (DCP), through the Waterfront Revitalization Program is putting forward efforts aiming to retrofit large sections of the city’s coastline into accessible waterfronts and urban amenities. On the other hand the Department of Environmental Protection (DEP) is moving forward with efforts aimed to improve water quality of the city’s waterbodies, the latest being the Combined Sewer Overflow Long Term Control Plan. More recently and after Hurricane Sandy, plans are being put forward to protect shorelines from rising seas and future storms, the most relevant examples being the federally funded competition Rebuild by Design and New York State initiative NY Rising Community Grant Reconstruction Program.

In the face of several waterfront planning and water management processes, crucial opportunities for civic participation emerge for Westchester Creek coastal communities. The outcomes of such plans will determine water quality improvements and the strategies developed to mitigate future floods for Westchester Creek. In order to enhance community participation and effective decision-making, it becomes paramount to empower civic groups and local governments by introducing strategies that aim to improve water quality and reduce coastal flooding.

Due to the social and environmental conditions

of the east Bronx, coastal green infrastructure often referred to as living shorelines, has great potential as being one of the primary strategies to mitigate flooding and improving water quality. I will discuss the potential of implementing coastal green infrastructure at Westchester Creek waterfront, develop scenarios with civic organizations and local government in order to encourage effective participation with decision makers.

Figure.2: Historical Map of Westchester and Pelham Towns. Image source: www.bronxhistoricalsociety.org

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1.3. Risks at Westchester Creek

Water QualityWater quality at Westchester Creek can be considered as a health risk. According to the Bureau of Watershed

Assessment and Management, from NYS Department of Environmental Conservation (DEC) Westchester Creek is stressed or impaired in all water body usage categories: Public bathing, fish consumption, aquatic life, recreation and aesthetics. Types of pollutants that contaminate the water body are oxygen demand, excessive nutrients, pathogens and floatables.

A combined sewer system serves the majority of the watershed, meaning that sewage water is mixed with rainwater into a single pipe system. During wet weather events, impervious surfaces create runoff water that is drained into the combined sewer system. Quite often during these storm events, the system reaches its maximum capacity and the untreated polluted water is released into the nearest waterbody. Such event is known as a Combined Sewer Overflow (CSO) and the discharge points are known as outfalls. Six CSO discharge points are distributed along Westchester Creek waterfront (DEP, 2014). Additional to this, separate sewers and direct runoff also discharge into Westchester Creek and contaminate the waterbody with garbage debris, excess nutrients and pathogens.

The NYC DEP estimates that approximately 1.1 billion gallons of waste water were discharged in 2013 into Westchester Creek. The majority of the discharged water comes from combined sewer overflows, accounting approximately 790 million gallons a year. Moreover, separate sewer discharges and direct runoff add to approximately 330 million gallons a year. The volume of these discharges is directly related to the size and distribution of Westchester Creek’s watershed: 4,270 acres are served by a combined sewer system, 340 acres are served by separate drainage system and the remaining 341 acres by direct runoff. Due to the interruptions of the water cycle at Westchester Creek, the quality has been degraded. Excessive levels of nutrients cause eutrophication, thus compromising dissolved oxygen and creating dead zones where aquatic life cannot be sustained, this is especially true in the upper portion of the creek (NYC DEP, 2014).

Constructed wetlands, bivalve communities and other examples of coastal green infrastructure are known to improve water quality through filtration, nutrient absorption and pollution removal. This paper will explore the opportunities for scaling coastal green infrastructure and provide insight to water filtration capacity and quality improvement based on previous research and case studies.

Figure.3: Poor water quality at Westchester CreekA. CSO outfall in the east Bronx. Photo by M. NegretB. Eutrophication and dead zones. Image source: www.flickr.com/photos/48722974@N07/4598769539

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Coastal FloodingSingle extreme events such as Hurricane Sandy cannot be completely attributed to climate change. However,

the NYC Panel on Climate Change states that the sea levels will rise over time, and that in the New York City area, it will very likely increase the incidence of coastal flooding during storms. By the 2050’s, the sea level rise mid-range projections for the City are estimated to be between 11-24 inches and high estimates are at 31 inches (NPCC report, 2013). Because of this, coastal flooding for Westchester Creek waterfront communities is very likely to increase, in frequency and in magnitude.

On October 29, 2012, Hurricane Sandy hit New York City claiming 44 lives and causing over $19 billion in damages and lost economic activity. Storm surge from the extreme weather event flooded large areas of Staten Island, Brooklyn, Queens and Manhattan. Flooding in the east Bronx occurred at City Island, Locust Point, Harding Park and in Ferry Point neighborhoods, but with less exposure to storm surge than southern portions of the city. If Sandy’s landfall had coincided with the timing of the hide tide of the Long Island Sound in the east Bronx, waterfront communities in that area would have experienced far more damage (SIRR report, 2013). The fact remains that Westchester Creek waterfront vulnerability to coastal flooding and storm surges is substantial and will increase in the following decades.

Living shorelines, constructed wetlands, constructed reefs, ecologically enhanced breakwaters and other typologies of Coastal Green Infrastructure are being extensively implemented for shoreline stabilization and flood mitigation in several east coast states and throughout the world. This paper will explore the opportunities for scaling the existing infrastructure and provide insight to potential flood mitigation capacity based on previous research and case studies.

Figure.4: Coastal flood risk in the east BronxA, NASA satellite photo of Hurricane Sandy. Image source: NASA getty imagesB. East Bronx Marinas near Westchester Creek. Photo by M. Negret

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2. PROJECT FRAMEWORK

2.1. Questions of Interest

• What is the potential of Coastal Green Infrastructure to mitigate flood risk and improve water quality at Westchester Creek?

• What opportunities and limitations exist to implement Coastal Green Infrastructure at Westchester Creek?

• How to empower local government and civic associations to advocate for Coastal Green Infrastructure in their coastal communities?

2.2. Project ClientMy involvement with communities in the East Bronx

initiated in fall of 2014 through the community fellowship-planning program sponsored by the Fund for the City of New York, a non-for profit organization that partners with government agencies, academic institutions and other foundations in order to improve quality of life for New Yorkers. The program matches graduate students from various academic institutions with planning efforts developed by New York City community boards. The goal of my project was to conduct a physical survey of the shoreline within boundaries of Bronx’s community board 10 and identify potential waterfront interventions to mitigate coastal flooding. The environmental and geographical conditions as well as the presence of large waterfront parks and productive tidal wetlands, suggest solutions that provide flood protection and ecological productivity to be feasible alternatives for the east Bronx shoreline.

Through this process, I developed significant working relations with several local government agencies and civic associations, most specifically with Bronx Community Board 10 and the East Bronx Coastal Working Group. During 8 months I was closely engaged with members of Bronx community board 10, including district manager Kenneth Kearns, chairperson Michael Prince, as well as members from the municipal services, open space and members of the committee for the NY Rising East Bronx waterfront community reconstruction program. Other local government institutions include the Bureau of Planning and Development of the Bronx President’s Office. Furthermore, community leader Dorothea Poggi was closely involved through the process and provided valuable insight of the historical and environmental

context of the area. Ms. Poggi is the founder of the East Bronx Coastal Working Group (part of the Bronx Council for Environmental Quality) as well as civic group Friends of Ferry Point Park.

The findings and recommendations of this project are aimed to inform and empower the local government and civic associations representing the waterfront communities of the East Bronx and more specifically those surrounding Westchester Creek. I will be communicating these issues with the aid of infographics and thematic maps. I expect that such visual aids will facilitate effective communication and encourage engagement along civic associations, elected officials and city agencies.

2.3. Scope of Work and GoalsThe proposed methodology can be described in five

steps: (i) Evaluate plans and documents released by city agencies and private sector addressing water quality and flood mitigation in the region. Identify critical interventions and strategies, relevant to the study area (ii) Conduct physical surveys and document existing conditions of Westchester Creek through map annotations and geotagged photos. Implement a series of transect walks guided by local community leaders. (iii) Conduct interviews with civic leaders representing the waterfront community to understand environmental concerns and evolution of the creek. (iv) Study Westchester Creek conditions following watershed-assessment methodology. Illustrate conditions through diagrams and maps. (v) Illustrate site-specific opportunities and benefits of coastal green infrastructure through design guidelines and schematic designs.

Figure.5: Project clients: East Bronx Coastal Working Group and Bronx Community Board 10A. Ms. Poggi during a clean up at Westchester CreekB. Mr. Kearns during a community event

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The previous methodology will allow achieving the following goals:

• Evaluate existing plans and proposed strategies addressing water management in the east Bronx.

• Study environmental, geographical and infrastructural conditions related to water management at Westchester’s Creek watershed and waterfront.

• Provide guidelines and recommendations to mitigate flood risk and improve water quality through coastal green infrastructure at Westchester Creek.

• Provide visualization tools to empower local government and civic associations in decision-making processes related with water management and waterfront planning.

2.4. First Hand Analysis and Physical Survey

Conducting physical documentation of the existing waterfront conditions, consisted on planning transect walks and bike routes. Classifications of coastal edge typologies were taken from the Urban Waterfront Strategies document produced by New York City Department of City Planning (DCP). Each typology was color coded and afterwards matched by marking maps with colored pens on the field. Instagram, proved to be a crucial documentation and community outreach tool throughout the first hand analysis process. I created an

Instagram account under the user name East Bronx Coast and promoted it during a Community Board 10 meeting in mid October (https://instagram.com/east_bronx_coast/). As the fieldwork was conducted, hundreds of geographically tagged pictures of the east Bronx coastline were posted online. One of the application’s features allows visualizing photographs on a map that indicates geographical location. By exploiting the open nature source of social media, the existing coastal edge was documented and community engagement was encouraged.

2.5. Westchester Creek Comprehensive Water Planning Tool

Ever since the earliest engagement experiences with my clients, the use of thematic maps became an important way to communicate and spark discussion regarding the issues related to Westchester Creek. As part of my GIS analysis (Geographical Information Systems) and by using a watershed-planning methodology, I began to develop a series of maps that helped narrate the story of Westchester Creek. The idea of designing a water-planning tool emerged only after exploring the potential of ArcGIS online interactive application. ArcGIS is a software used by urban planners, geographers and environmental managers to help relate quantifiable information with visual representations of the physical environment.

I designed the Westchester Creek Comprehensive Water Planning Tool (WCCW planning tool) to assist local government and civic associations by illustrating existing conditions, associated risks, ongoing planning efforts and opportunities for Coastal Green Infrastructure at Westchester Creek. The tool is based on ESRI’s ArcGIS online platform and uses the story map application. Users can navigate the tool with any conventional Internet browser, enabling them to explore the challenges and opportunities related to Westchester Creek. 15 maps compose the WCCW planning tool, as users switch themes relevant information will be highlighted, the sequence of the maps will then create a cohesive narrative. A side bar provides a brief description of the theme, as well as supporting photos or diagrams and linking information to relevant websites. The tool serves as an integrating resource for multiple stakeholders and processes related to Westchester Creek. Moreover, it empowers engaged community members by delivering information in a concise fashion, creating connections and encouraging users to develop an informed opinion regarding the issues affecting Westchester Creek.

Figure.6: Westchester Creek study area

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Figure.7: Geotagged photos from first hand analysis. Image source: www.instagram.com/east_bronx_coast/

Figure.8: Digital interface of WCCW Plannning Tool. Image source: www.arcg.is/1ySmSG5

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3. EXISTING CONDITIONS

3.1. Watershed – Waterbody overviewWestchester Creek is a tidal inlet of the upper East

River and is located in the eastern part of the Bronx. According to the Department of Environmental Protection (NYC DEP, 2014) Westchester Creek watershed lies in Bronx community districts 9, 10 11 and 12, covering a total area of 4,950 acres. Approximately 86% of the area (equivalent to 4,271 acres) is served by a combined sewer system, 7% of the area (340 acres) is served by separate drainage (storm water outfalls), and the remaining 7% (341 acres) corresponds to direct runoff. The waterbody currently extends approximately 2.5 miles and the width varies between 200 and 3,000 feet. Pugsley Creek, located south of Castle Hill is a much smaller tidal inlet of the East River. Because of the current hydrological conditions, Pugsley Creek and Westchester Creek are managed as a single waterbody (NYC DEP, 2014).

3.2. Waterfront CommunityAccording to Mr. Kenneth Kearns, Bronx born and

District Manager for board 10 over the last decade, most communities in the east Bronx consider themselves highly independent and having a strong relation with their waterfront. This can be partially explained because of geographical and historical conditions. Up until the late 19th century large portions of the East Bronx where physically disconnected by Wetlands and tributaries of Westchester Creek and Hutchinson River, during that time the area named Westchester Town was not part of New York City. After significant urban development, and in spite of having strong local opposition, the state legislature annexed the area east to The Bronx River in 1895. By 1898, all of the annexed areas officially became the borough of the Bronx (Virden, 2005). The sentiment of being an independent community remains after several generations and over a 100 years.

The coastal geography of the East Bronx, encouraged development of important cultural and economical conditions that depended on their waterfront: boat builders, commercial marinas and seafood restaurants. Even tough relations with their coastal economy and culture have eroded; many of these key drivers that maintain a strong link between the community and the waterfront are still in place.

The East Bronx has historically had a large German and Italian American white population. The geography of Westchester Creek and the limited mobility around it, has served as a physical boundary separating communities with different ethnicities, income and age group. This is evident when observing demographic composition by census track. However according to the 2010 census, ethnic demographic trends show increasing amounts of Hispanic population within the watershed area, Castle Hill and Parkchester (West side of Westchester Creek) show over 50% of Hispanic population. Even though that the East side of the creek remains mostly white, a few blocks in Schuylerville and Ferry Point south overcome 75% of Hispanic population. Similarly to the ethnic distribution, the median household is considerably lower on the west portion of the creek (Castle Hill and Parkchester) and much higher on the east side (Throggs Neck). By following existing trends, it is expected that the East Bronx will continue to diversify with more Hispanic population.

3.3. History of Westchester Creek Watershed

The physical boundaries of the historical watershed have dramatically changed due to urban development and construction of sewage infrastructure. Up until the beginning of the 20th century, Westchester Creek was hydraulically connected to Hutchinson River through approximately 600 acres of interrupted marshlands. Because of this Throgs Neck, Spencer States and Baychester were isolated from the mainland. Based on topography it can be estimated that the historical watershed was only 3,600 acres, approximately 30% smaller than the existing conditions (NYC DEP, 2014). Moreover, the creek used to naturally reach of what today is the neighborhood of Pelham Gardens, stretching approximately 3.9 miles up north. Pugsley Creek watershed was separate and connected to the Bronx River, thus considered to be its own waterbody. After decades of urban development, hundreds of acres of tidal wetlands and mudflats have been eliminated. This reduced the size and length of Westchester Creek considerably; currently the waterbody has an approximate length of only 2.4 miles. The alteration of the watershed-waterbody ratio (enlargement of watershed and reduction of waterbody) makes Westchester Creek more vulnerable to poor water quality and coastal flooding.

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Figure.9: Westchester Creek historical watershed and wetlands. Map by M. Negret

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Figure.10: Westchester Creek existing watershed and outfalls. Map by M. Negret

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3.4. Tidal WetlandsExisting tidal wetlands at Westchester Creek are

designated by New York State Department of Environmental Conservation and thus are protected under law (PlaNYC Wetlands Strategy, 2012). Tidal Wetlands are important ecosystems that provide multiple services such as flood protection, prevent coastal erosion, allow for groundwater recharge/discharge, improve water quality and provide habitat for wildlife species (EPA, 2013). Tidal Wetlands at Westchester Creek are located in three sections along the shoreline: on the edge of the west portion of Ferry Point Park, delineating Pugsley Creek and a smaller portion located at the height of Lacombe avenue on the west side of the creek. The total area of the existing Tidal Wetlands is approximately 42 acres, stretching 3.5 miles and having an average width of 35 feet. According to the Land and Waters division of NYS DEC there are three categories of wetlands remaining at Westchester Creek: HM-High Marshes with 2 acres approximately, IM-Intertidal Marshes with approximately 11 acres and SM Coastal Shoals, Bars and Mudflats with approximately 29 acres. High Marshes are classified as 4000 HM, and are defined as the upper zone of the wetland, usually dominated by salt meadow grass and spike grass, this zone is flooded during spring and storm tides. Intertidal Marshes are classified as 3000 IM and defined as the zone located at the average elevation of high and low tidal elevation, predominantly vegetated by low marsh cordgrass. Coastal Shoals, Bars and Mudflats are classified as 2010 SM, which are covered by tidal waters at hide tide and exposed during low tide, mudflats are not vegetated but host a variety of macrobenthic communities (NYS DEC, 2015).

Due to fragmentation and eutrophication the ecological condition of the wetlands can be considered stressed (NYS DEC, 2011). Excessive levels of nutrients cause eutrophication, thus compromising dissolved oxygen and creating dead zones where aquatic life cannot be sustained, this is especially true in the upper portion of the creek (NYC DEP, 2014). Alteration of shoreline and water conditions has dramatically reduced biodiversity in the area; under such conditions Phragmites australis (Common reed), an exotic wetland grass species with invasive tendencies, is thriving and in many areas dominating the landscape. In spite of this, significant populations of oysters, ribbed mussels, cordgrass and other shallow marsh vegetation can be found interacting in symbiotic relations. These facilitator species create structures of living systems that effectively increase shoreline length and create habitat areas for spawning

fish and wildlife, while at the same time preventing erosion, reducing wave action, absorbing excessive nutrients and reducing pathogen levels (Hughes et al. 2013).

3.5. Ecological CommunityThe first hand analysis confirmed the tidal wetlands

conditions designated by DEC. By conducting the survey in fall of 2014 and in early spring of 2015, vegetation and bivalve conditions where documented in contrasting seasons. During the fall survey significant populations of species with invasive tendencies such as Phragmites australis (common reed), Ailanthus altissima (tree of heaven), Rhus Typhina (staghorn sumac) and Gleditsia triancathos (thorny honey locust) where located at the High Marsh areas. In spite of the invasive classification of such species, it can be argued that they are in fact providing ecosystem services such as preventing erosion, stabilizing shorelines and absorbing excessive nutrients. An increasing amount of studies have concluded that both native and exotic species provide functional value in urban systems, specially if left undisturbed long enough to develop into mature woodlands (Del Tredici, 2010).

During the early spring survey, the intertidal marshes were more accessible due to the lack of vegetation in the higher portion, thus allowing documentation of bilvalve and cordgrass communities. I found communities of Geukensia demissa (Ribbed mussel) had established independent relations with facilitator host plant, Spartina alterniflora (Saltmarsh cordgrass), such communities where most common and abundant in the West portion of the Waterfront, especially at Pugsley Creek. Saltmarsh cordgrass can establish and persist without the aid of other foundation species, facilitating a dense assemblage of inhabitants (musses, snails, seaweeds). The roots stabilize substrate and a dense canopy mitigates waves and provides shade. Furthermore, within the cordgrass community, ribbed mussels enhance physical conditions by creating hard substrate and surface area for the establishment of amphipods and barnacles (Altieri, et al. 2006). The existence of such communities in the intertidal marshes provides valuable insight to the feasibility of increasing the scale of living shorelines in the area. In spite of the degraded conditions, the wetlands are able to support cordgrass and mussel communities. In other words, the chances of ecological restoration through man made interventions, improves considerably when using specimens that are thriving in the environmental conditions of the creek.

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Figure.11: Westchester creek NYS DEC designated tidal wetlands. Map by M. Negret

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Figure.12: Spartina Alterniflora, Honey Locust and Ailanthus Altissima at Westchester creek. Photos by M. Negret

Figure.13: Phragmites Australis and Ribbed Mussels at Westchester creek tidal wetlands. Photos by M. Negret

Figure.14: Cordgrass Spartina Alterniflora at Westchester creek tidal wetlands. Photos by M. Negret

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3.6. Population, Land Use and Ownership

According to the 2010 census 232,000 people live and 89,000 housing units exist within Westchester Creek watershed area. The predominant land use for the entire watershed is residential with 55% (most being 1-2 family buildings), followed by mixed use with 18% and open space with 15%. Most of the land in the upper portion of the waterfront is used for industrial purposes, but only accounts 4% of the entire watershed area. It is worth noting that several large parking lots and vacant land are located in the west shore and mid section of the creek (between Norton and Lafayatte avenues). Other common Industrial uses in the upper section include parking facilities, warehouses and transportation utilities. In spite of the surrounding existing open space, most of the creek is encroached by cemeteries, highways and industrial uses, which greatly limit public access.

Ferry Point Park, with over 410 acres, is located to the east of the creek and plays a critical role for future Coastal Green Infrastructure implementation. The Whitestone Bridge physically divides in two sections Ferry Point Park. The east 200 acre portion of the park was used as a landfill for urban solid waste from 1952 until the 1970’s, covering a historical marshland called Baxter Creek. Later during the 80’s and through the 90’s it was covered by construction debris and demolition material. Because of Ferry Point’s landfill history, the city was obliged to provide environmental remediation (Foderaro, 2015). Since the late seventies a public golf course was envisioned, but due to the toxicity of the soil and because of failed deals with developers the project got delayed over three decades. Finally, on April 1st of 2015 the 192 acre Luxury Public Golf Course made a soft opening under the management of Trump National and International Golf Courses. Additional amenities for the community were initially part of the project: including a 19 acre community park, which was completed in 2014 and a waterfront esplanade to the south which is still pending and with an uncertain opening date.

A large, yet neglected portion of Ferry Point Park is located west to the Whitestone Bridge, the 110 acre area offers public waterfront access to Westchester Creek and several active space amenities, including 8 soccer fields and 2 cricket fields. At a higher elevation and towards the southern tip of the park, the 911 living memorial forest provides an unique view towards Manhattan’s skyline. In spite of this, the only route to gain access to this part of the waterfront is by driving from north of the park through Brush avenue or by the

Hutchinson River Parkway. Such restrictions limit public access to Westchester Creek to the Throgs Neck and Ferry Point communities. The planned waterfront esplanade, located south of the golf course could provide a vital role in reconnecting the west portion of Ferry Point Park; unfortunately the project has been delayed with unknown completion date. Due to the open space classification, the nearby shallow waters and adjacent tidal wetlands, Ferry Point Park waterfront provides promising circumstances to scale Coastal Green Infrastructure.

Pugsley Park is located on the West side of the creek, serving communities of Clason Point and Castle Hill at Bronx Community Board 9. Similarly to Ferry Point Park, Pugsley Park waterfront also offers promising opportunities for Coastal Green Infrastructure implementation. After many decades of being neglected, the city has embarked on plans to rehabilitate Pugsley Creek. The department of Parks and Recreation has rehabilitated portions and improved waterfront access along Barrett Avenue. The area surrounding Pugsley Creek offers several bus routes and is not encroached by industry or cemeteries, which makes it much more accessible to the public than Ferry Point Park. Because of its accessibility, shallow waters and healthy tidal wetlands, Pugsley Creek offers almost ideal conditions to scale Coastal Green Infrastructure.

The most common ownership type of industrial waterfront lot on the East side of Westchester creek is private development with M-1 zoning. On the other hand, waterfront lots on the west side are mostly city owned as well as owned by state or federal public authority and mostly zoned as M-1. The presence of waterfront parks makes NYC Department of Parks and Recreation a major stakeholder for any potential interventions. Several lots on the West waterfront of the Creek between Lacombe Avenue and Bruckner Expressway are operated by the MTA and Department of Sanitation. The large presence of city or state agencies makes the role of government crucial in the revitalization of the creek. Multi agency collaboration will be required in order to implement any substantial improvements to the area.

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Figure.15: Population density per census track within Westchester Creek watershed. Map by M. Negret

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Figure.16: Land Use at Westchester Creek. Map by M. Negret

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Figure.17: Lot ownership at Westchester Creek. Map by M. Negret

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3.7. Shoreline ConditionsShoreline conditions of Westchester Creek waterfront

used to be a series of interconnected mudflats, tidal wetlands and maritime forests that extended over dozens of linear miles. The present shoreline for Westchester Creek is estimated to be 7.25 miles long, using the southern tips of Ferry Point Park and Shorehaven neighborhood as boundaries. While performing the physical survey, three general conditions along the shoreline where identified: rip-rap revetments, seawalls and remaining tidal wetlands. Rip-rap revetments are made out of boulders and rocks. These structures constitute approximately 4 miles of the shoreline, with significant variations in height and structural robustness, mostly due to boat landings and docks. Sea walls constitute approximately 1.5 miles and are mostly concentrated along industrial and privately owned lots in the upper portion of the creek. The remaining tidal wetlands add 1.75 miles and are located in the lower southern portion of the creek, below Lafayette Avenue (for more detailed distribution of wetlands see previous section).

3.8. Topography and BathymetryThe median elevation of Westchester Creek Waterfront

is approximately 15 feet above sea level. The highest point in the area is the natural mound formation located in the southeast portion of Ferry Point Park with approximately 35 feet above mean water level. The lowest lying areas of the waterfront are the remaining portions within east Ferry Point Park with a range from 0 - 8 feet above mean water level. Other areas of the waterfront with low elevations are the current Multiplex cinemas west to Schuylerville cemetery, portions of castle hill shoreline as well as most of Westchester Square with elevations between 3 – 10 feet.

Urban development has also drastically modified topographical conditions of Westchester creek waterfront. Perhaps the most noticeable alteration has been the

construction of the former landfill on the west portion of Ferry Point Park, currently a public Golf Course operated by Trump Golf Clubs. The southern tip of East Ferry Point Park used to be a much more pronounced peninsula. After the allocation of the landfill in the 1960’s, over 100 acres of Tidal Wetlands were destroyed. The crescent shaped shoreline on the east side of the Whitestone Bridge was built with rip-rap after the closing of the landfill in order to prevent erosion. Elevations at the former landfill oscillate between 15 to 20 feet above median water level, making it several feet above surrounding residential neighborhoods South Ferry Point and West Throgs Neck.

The median depth of Westchester Creek channels is approximately 10 feet below sea level. Bathymetry maps indicates that the deepest areas lie in the Upper east river navigation channel, with portions going as deep as 90 feet below sea level. Navigation channels in Westchester Creek were once highly transited. However, in recent decades sediment accumulation has limited navigation of such channels, with some upper portions of the creek having less than 8 feet of depth. Depths in areas adjacent to Ferry Point Park and Pugsley Creek (outside from the navigation channel) are relatively shallow as well, ranging between 5 and 8 feet below median water level. These shallow areas adjacent to Ferry Point Park and Pugsley Creek, offer promising conditions to restore Tidal Wetlands and creation of ecological breakwaters.

Figure.18: Shoreline typologies at Westchester Creek. Categories by Urban Waterfront Strategies. Diagram by M. Negret

1.75 miles24%

Wetlands SeawallsRevetments

4 miles56%

1.5 miles20%

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Figure.19: Topography and bathymetry at Westchester Creek. Map by M. Negret

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4. RELATED REGULATORY AND PLANNING FRAMEWORK

4.1. Waterfront Revitalization Program

New York City’s Waterfront Revitalization Program (WRP) is the City’s principal coastal zone management tool. The program has the purpose of maximizing benefits derived from economic development, environmental health and public use of the waterfront. The program is authorized by New York State policy (Waterfront revitalization of coastal areas and inland waterway act), which derives from the Federal Coastal Zone Management Act (2012, NYC DCP).

Since the earliest version of the Waterfront Revitalization Program from 1982, coastal zones where established, defining the boundaries of where the policies would be applicable. The coastal zone of the east Bronx includes the entire waterbody of Westchester Creek as well as large sections of Westchester Square, Castle Hill, and Ferry Point neighborhoods. Furthermore, the WRP defines special areas in which policies aimed towards economy,

public access, or the environment would have priority over the others based on the designated area.

Significant portions of Westchester Creek waterfront lie within the Special Natural Waterfront Area, one of the five special coastal zones defined by the WRP. The program defines the SNWAs as “Large areas with significant open spaces and concentrations of the natural resources including wetlands, habitats, and buffer areas” (2013, NYC DCP). The policies that would priority in this area focus on habitat protection and improvement of the coastal ecosystems within the area. On the other hand, such policies discourage activities that interfere with coastal habitat functions, including further fragmentation or loss of habitat areas within the SNWAs. Areas surrounding Westchester Creek that are included within the Special Natural Waterfront Area are Ferry Point Park, Pugsley Creek Waterfront Park and the totality of the waterbody lying south of Randall Avenue. These policies will most likely determine consistency with the Waterfront Revitalization Program, allowing or modifying the scope of future projects within the coastal zone. The overarching regulating policies related to ecological protection and restoration within the SNWAs are the following:

• Protect and restore the ecological quality and

component habitats and resources within the SNWAs.Protect and restore tidal and freshwater wetlands.

• In addition to wetlands, seek opportunities to create a mosaic of habitats with high ecological value and function that provide environmental and societal benefits. Restoration should strive to incorporate multiple habitat characteristics to achieve the greatest ecological benefit at a single location.

• Protect vulnerable plant, fish and wildlife species, and rare ecological communities. Design and develop land and water uses to maximize their integration or compatibility with the identified ecological community.

• Maintain and protect living aquatic resources.

In addition to the policies aimed to improve ecological quality, the Waterfront Revitalization Program also provides regulations on protecting and improving water quality within the coastal areas. The set of policies acknowledges pollution from both point and non point sources: water from wastewater treatment plants, combined sewer overflows and storm water from impervious runoff. This portion of the WRP aims to promote New York’s water quality through infrastructure improvements, greening strategies, and promoting and Figure.20: East Bronx Coastal Zones. Map by NYC DCP

Waterfront revitalization Program

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Figure.21: Special Natural Waterfront Areas in the Bronx. Map by NYC DCP Waterfront revitalization Program

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enhancing biodiversity and ecological functions. Key policies related to water quality are:

• Manage direct or indirect discharges to waterbodies

• Protect quality of waters by managing activities that generate non point source pollution

• Protect water quality when excavating or placing fill in navigable waters and in or near marshes, estuaries, tidal marshes, and wetlands.

• Protect and improve water quality through cost effective grey infrastructure and in water ecological strategies

The Waterfront Revitalization Program and policies regulating the Special Natural Waterfront Areas and water quality improvements will play a crucial role in future development at Westchester Creek. Studies aiming to reduce flood risk, improve water quality and ecological improvements must comply with regulations set by the WRP. Related studies and plans that are underway at Westchester Creek include the NY Rising Westchester Creek Waterfront Study and CSO Long Term Control Plan by DEP, both will most likely be required to comply the WRP policies. Policies from the WRP aim to improve water quality and ecological performance set a robust legal framework where coastal green infrastructure strategies emerge as an outstanding alternative for coastal zones such as Westchester Creek.

4.2. Coastal Green Infrastructure Research Plan for New York City

In January of 2015 the Coastal Green Infrastructure Research Plan for New York City was released. The plan headed by the NYS Department of Environmental Conservation, NYC Department of City Planning and the New England Interstate Water Pollution Control Commission aims to document scientific research and identify knowledge gaps to improve decision making, related to implementation and management of natural based infrastructure. The plan sets a research agenda and lays out specific questions addressing knowledge gaps that will help determine flood resiliency improvements offered by Coastal Green Infrastructure. Ultimately, the goal of the plan is to provide cost benefit analysis and develop specific guidelines for Coastal Green Infrastructure implementation, policy update and decision-making for coastal areas in New York City. The CGI research plan is discussed in further detail during the following chapter.

4.3. Waterbody Classification and Usages

NYS DEC has classified Westchester Creek as class I waterbody. Designated usages for this classification are secondary contact recreation and fishing, also suitable for fish, shellfish and wildlife propagation and survival, but not consumption. According to the NYS DEC the waterbody is stressed or impaired in all water body usage categories: Public bathing, fish consumption, aquatic life, recreation and aesthetics. Types of pollutants that contaminate the water body are oxygen demand, excessive nutrients, pathogens and floatables. The most common sources of such pollutants are combined sewer overflows and urban storm runoff (DEC Bureau of Watershed Assessment and Management, 2011).

The most crucial indicator used to determine waterbody criteria and pollution is the presence of pathogens, currently Fecal Coliform. In the near future it is expected that measurement of pathogen Enterococci will be used to determine a more accurate representation of water quality. In order to reach future primary contact water quality criteria, it is expected for Enterococci levels to remain at least under 110 cfu/100mL for the 90th percentile (the percentile is used to represent the variation of pathogen levels under different weather conditions). In other words, desirable water quality criteria require pathogens levels to remain as low as possible, including after significant wet weather events.

Figure.22: Kayaking activies at Ferry Point Park in Westchester Creek. Photo Credit: Dorothea Poggi

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4.4. Combined Sewer Overflow Consent order

The CSO Order on Consent tasks the DEP to submit and implement watershed facility plans for 11 waterbodies, some strategies include upgrading existing parts of the sewer system and wastewater treatment plans, in year 2012 the consent was amended to include Green Infrastructure as an alternative measure. One of the first steps in mitigating CSO at Westchester Creek was the Watershed and Waterbody facilities plan, approved in 2011 and scheduled for completion by 2019. More recently NYC DEP has embarked on waterbody specific CSO Long Term Control Plans. The main goal of each LTCP is to identify appropriate CSO controls to achieve waterbody specific quality standards.

The current proposals made by the CSO LTCP for Westchester Creek seem unrealistic and far from being cost effective. Since the plan has not been approved and the city is nevertheless required to implement a CSO mitigation strategy, an important opportunity for Coastal Green Infrastructure emerges for Westchester Creek. The CSO LTCP for Westchester Creek specifies that where proposed alternatives set forth will not achieve existing water quality standards, the DEP will include a

use attainability analysis examining whether applicable waterbody classifications, criteria, or standards should be adjusted by NYS DEC. In other words, the plan leaves the possibility for the DEP to negotiate with DEC the water quality criteria or redefine the usage classifications for Westchester Creek. Under this scenario and based on the unrealistic proposals made by the plan, it can be expected that the city agency will attempt to redefine the usage classifications for the creek. If this previous scenario occurs, it would be a vivid example of flawed environmental policy, sentencing Westchester Creek to poor water quality.

Up until May of 2015 the plan has not been approved by the DEC, leaving the possibility for a close reevaluation of the proposed strategies. Under these circumstances an opportunity for demanding the plan not only to incorporate more Green Infrastructure for stormwater management but for encouraging direct pollutant removal through constructed wetlands. Up until spring of 2015 and prior to mitigation efforts the DEP estimates that 791 million gallons of CSO are being discharged annually into Westchester Creek. Discharging outfalls are: HP 014 contributing 442 MGY, HP 013 contributing 204 MGY, HP 016 contributing 76 MGY, HP 012 contributing 55 MGY and HP 033 contributing 13 MGY.

DEP Water Quality Plans for Westchester CreekExpected CSO discharges in million gallons a year after plan implementations and corresponding cost per MGY

Future CSO discharge scenarios791 MGY

289 MGY224 MGY* 181 MGY 97 MGY

The DEP does NOT expect to meet criteria for future primary contact (class SC) even at 100% CSO control

Consent Order WWFP GI Stormwater Plan LTCP Throgs Neck FM Extention

LTCP Inline Storage23 MG Tunnel

Cost per MGY $352,000

Cost per MGYreduced

MGYreduced

Cost per MGY $3,100,000

Cost per MGY $169,000

Cost per MGY $4,100,000$

Figure.23: Cost benefit chart for each CSO mitigation plan at Westchester Creek. Data from DEP, Diagram by M. Negret

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Figure.24: Current outfall discharges at Westchester Creek. Map by M. Negret

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Figure.25: Outfall discharges after WWFP implementation at Westchester Creek. Map by M. Negret

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Figure.26: Outfall discharges after LTCP implementation at Westchester Creek. Map by M. Negret

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4.5. Waterbody Watershed Facilities Plan

The approved Waterbody Watershed Facilities Plan for Westchester Creek consists of two different grey infrastructure interventions: Pugsley creek sewer extension of HP 013 and weir improvements at HP 014 in the upper end of the creek, both projects are estimated to have a cost of $177 million dollars and are scheduled for completion by year 2019. NYS DEC approved the plan in 2011, technical designs are under way by the DDC (Department of Design and Construction) and construction is scheduled to initiate in spring of 2015.

The HP 013 sewer extension will divert over 200 million gallons of CSO from Pugsley Creek, sending the wastewater to Hunts Point Waste Water Treatment Plant and into outfall HP 011 where it will be discharged into the East River. The rationale is that due to the small size of Pugsley Creek, the current CSO volume has an overwhelming impact on the waterbody, thus by extending the sewer and discharging into the East River (outfall HP 011) the wastewater will be effectively diluted into the much larger waterbody. It can be argued that this intervention is not improving water quality, but only externalizing the problem into a different system. The previous becomes evident when preliminary observations by the CSO LTCP for the Bronx River are predicting an increase of CSO discharges in the lower portion of the river. On the other hand improvements at HP 014 will rely on the wet weather capacity from Hunts Point Waste Water Treatment Plant. This relative simple intervention consists on increasing the height of the outfall weirs (a small-scale dam that regulates water flow). With this improvement, the volume of water from the combined sewer that is sent to Hunts Point WWTP will significantly increase. Under most wet weather events, wastewater will bypass the outfall and be transported to Hunts Point for treatment.

The DEP estimates that the implementation of WWFP will reduce CSO discharges from 791 MGY to 289 MGY by 2019 at a total cost of $177 million. The cost for the interventions is $352,000 dollars per avoided MGY of combined sewer overflows. Because of this, the previous interventions can be considered as cost effective grey infrastructure for CSO mitigation.

4.6. CSO Long Term Control PlanWestchester Creek LTCP was submitted in June 2014

for review to NYS DEC. Based on published correspondence between the state and city agencies,

the DEP has committed to revise models used to determine ratios between CSO volume and pathogens, setting a deadline to resubmit the plan by late February of 2015 (correspondence between DEP and DEC, 2014). As to April of 2015 the plan has not been published or approved by the DEC and without further due date. For this paper I examined the latest available document published in June of 2014.

The DEP planned their monitoring system in order to create a baseline model to predict future scenarios and potential impact from interventions. Between December 2013 and April 2014 the DEP collected water samples to determine amounts of Enterococci and Fecal coliform bacteria. Results from the sampling period showed high-elevated concentrations, especially after wet weather events and within the inner creek area (single wet weather sample excursions reach 30,000 cfu/100mL for enterococci 50,000 cfu/100mL for fecal coliform). Even though water quality meets existing criteria for Class 1, the inner area does not meet primary contact criteria (class SC) failing to reach the 90th percentile limit of Enterococci statistical threshold value.

By modeling future scenarios from their baseline, the plan recommends strategies using gray infrastructure solutions; it highlights the Throggs Neck PS force main extension and the creation of a deep inline storage tunnel to capture outfall from HP-014, with ranging capacity between 24.5 and 50 MG. In spite of the improvements the plan acknowledges that Future Primary Contact criteria will not be met, especially in the inner portion of the creek. In the plan the DEP recommends implementing a use attainability analysis, suggesting the DEC to consider adjusting waterbody classifications or water quality criteria based on the potential of the suggested alternatives. In other words, DEP is suggesting implementing less stringent water quality criteria or as an alternative downgrading Westchester creek usage classification to class SD. In both cases water quality at Westchester creek will remain stressed or impaired in most usages.

The expected improvements from Westchester Creek CSO LTCP are not encouraging when comparing the cost benefit analysis with the preceding of the Waterbody Watershed Facilities Plan. Depending on the selected strategy estimated costs range from $137 million dollars to $530 million dollars and expected CSO reductions range from a modest 43 MGY to 127 MGY. Under this scenario, the cost for the interventions could be up to $4,170,000 dollars per avoided MGY of combined sewer

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overflows, making it eleven times more expensive than the WWFP interventions. Perhaps even more discouraging about the plan is that in spite of such costly interventions, the DEP models indicate that future water quality criteria would still not be reached, providing the argument to pursue a use attainability analysis and downgrading Westchester Creek even further from class I to class SD.

4.7. Green Infrastructure Plan for stormwater management

The CSO LTCP for Westchester creek acknowledges the implementation of Green Infrastructure as a way to improve water quality; unfortunately it is not included in the cost performance analysis, thus fails to propose interventions beyond the goals established by the city wide Green Infrastructure Plan. According to the Long Term Control Plan, the goal for Green Infrastructure is to manage storm water for 14 percent of the CSO tributary impervious areas. Since DEP estimated total impervious surface for Westchester Creek watershed to be 3,480 acres, Green infrastructure will manage tributary storm

water from 487 acres. By 2030, the DEP expects to reach their goal by implementing Green Infrastructure in the following way: 10 percent (corresponding to 348 acres) to be managed using green infrastructure right-of-way-bioswales (ROWBs), 3.5 percent (122 acres) to be managed in onsite private properties through new development and compliance with the Stormwater Performance Standard and 0.5 percent (17 acres) to be managed in onsite public properties.

None of the modeled scenarios for Westchester creek included green infrastructure for stormwater to evaluate cost performance and water quality improvements based on pathogen reduction. The document explains that green infrastructure was approved as an alternative solution only after the renewal of the CSO consent order in 2012, arguing that the Waterbody/Watershed Facility Plan (WWFP) had been completed before this, hence its limitation to include green infrastructure in modeled scenarios. However, this argument is objectionable since the plan was produced two years after (June, 2014) and most of sampling period was realized in early 2013.

The milestones set by the citywide Green Infrastructure Plan aim to manage 1.5% of the impervious tributary area by 2015. Based on the previous, 7.3 acres of Westchester creek tributary impervious surfaces should be managed by Green Infrastructure by 2015. Unfortunately, the only two green infrastructure projects that have been completed within Westchester Creek watershed are Falk Building Green Roof for Einstein Medical College (with a built space of 0.39 acres and within drainage area of HP 014) and a public retrofit within drainage area of HP 033, with unknown water

Figure.28: Green Roof at Einstein College of Medicine within Westchester Creek watershed. Photo credit: Gaia Institute

Figure.27: Proposed deep inline storage tunnel for Westchester Creek. Image source: DEP LTCP

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management capacity. Based on the previous, it is clear that the 2015 milestone will not be achieved and missed by far. In face of the costly proposals made by the LTCP for Westchester Creek, Green Infrastructure for stormwater should not only be achieving goals set by the citywide plan but going beyond than the established 487 acres. Even tough Green Infrastructure for stormwater management is not the focus of this paper; it is evident that the proposed scale should be reconsidered to managing a much larger area.

4.8. Stormwater Outfalls and Direct Storm Runoff

Westchester Creek tributaries from separate sewered areas and direct stormater runoff have a combined area of 680 acres. The DEP estimates that approximately 327 MG are discharged annually into Westchester creek from such sources. The separate sewer areas discharge into nine outfalls (also known as MS4 or municipal separate sewers). Stormwater runoff on the other hand comes from waterfront parks and open space discharging directly into the water. Information indicating drainage areas for individual direct outfalls and storm runoff is not specified in DEP documents. The maps from the CSO LTCP illustrate drainage areas from direct outfalls and storm runoff as a single tributary, as opposed to individual and separate sources. Because of this, identifying scale and defining management capacity of potential green infrastructure interventions will be challenging. Estimations to define drainage areas should be then based on topography and imperviousness.

By carrying garbage debris as well as oil and heavy metals from parking and industrial lots, rainwater from separate sewer areas and direct storm runoff has significant negative impacts on the water quality of the creek. The importance of mitigating these impacts will become more evident once CSO reduction efforts from the DEP have been implemented. The Westchester Creek CSO LTCP acknowledges that these tributary areas as well as incoming flow of water from the East River, have an important role in degrading water quality at Westchester Creek. DEP models predict that even with 100% CSO reduction, water quality is not expected to meet primary contact criteria, arguing that discharges from separate sewers and direct storm runoff contaminate water with pathogens and other pollutants. Unfortunately, at the moment there is no consent order in place that would force the DEP to mitigate discharges from separate sewers. Once again this offers a promising opportunity for considering Coastal Green Infrastructure as a viable alternative. Since coastal green infrastructure has the

ability of rmoving pollutants on site, it will improve water quality equally without regards of origin, pervious runoff, CSO or a MS4. Even without a specific consent order to address MS4 areas, coastal green infrastructure will be improving quality of water from pollutants originated in these areas.

4.9. Future Flood plains projections by NPCC

To estimate the potential impacts of sea level rise on the 100 and 500 – year flood zones, the NYC Panel on Climate Change (NPCC) developed maps that incorporated projections of sea level rise with FEMA’s 2013 Preliminary Work Maps, illustrating trends of future flooding for these events. These maps indicate that large portions of the East Bronx are within the floodplains including: coastal areas, waterfront parks, and even inland neighborhoods such as Westchester Square and portions of Co-Op city. Furthermore, over 50% of the area within Bronx Community Board #10 is considered to be at flood risk according to the NY Rising Coastal Inundation Risk Assessment. Both maps delineate very similar flood and risk zones, however the NY Coastal Inundation map incorporates larger areas into moderate risk zones, such as: Eastchester Bay, Westchester creek (Ferry Point) and Hutchinson River (Co-op City).

Hurricane Sandy exposed New York City’s vulnerability and helped initiate important processes to address flood risk. However, it is a mistake to base long term plans in response to a single event. Certain areas of the city have received little to no attention in such matters; one of them is the east Bronx. Flooding from hurricanes, nor’ easters and storm surges are hazards that will continue to increase in the coming decades as sea level rises and weather becomes more erratic. If plans and new infrastructure fail to materialize, it is very likely that increasing exposure to flood risk will make the area less attractive for investment. As flood hazards increase both in frequency and in magnitude, disinvestment will degrade the existing communities. Moreover, as rising seas displace tidal wetland ecosystems, the waterfront will become even more vulnerable to flood risk, and the surrounding neighborhoods would be entering a cycle of urban deterioration. The east Bronx urgently requires planning and infrastructure inputs, in order to reduce exposure and vulnerability of economic assets, communities and ecosystems. The presence of Tidal Wetlands and waterfront parks in the east Bronx offer opportunities for scaling Coastal Green Infrastructure and substantially mitigating coastal flooding.

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Figure.29: 100 year floodplains + projected sea level rise by year 2050. Map by Marcel Negret

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Figure.30: 100 year floodplains + projected sea level rise by year 2050. Map by Marcel Negret

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4.10. East Bronx Resiliency PlanningAfter Hurricane Sandy, the City of New York initiated

multiple efforts to improve its resiliency: comprehensive planning efforts, the creation of the special initiative for rebuilding and resiliency (SIRR), resilient neighborhoods program by the Department of City Planning and over $4 billion dollars have been awarded by the Department of Housing and Urban Development (HUD) through the Community Development Block Grant Disaster Recovery program (CDBG-DR). However, such efforts have not been equally developed throughout the city. Waterfront communities at Westchester Creek have had little to no participation in these important planning processes.

The plan proposed by the Special Initiative for Rebuilding and Resiliency also known as the SIRR report, is perhaps the most relevant document regarding coastal flood planning for New York City. In the first iteration of the SIRR the east Bronx is not included in Phase 1 of the implementation and mentioned only a few times throughout the document. Proposed strategies for the east Bronx are very general and only suggest non-specific locations of potential strategies:

• Wetlands with wave attenuation along Hutchinson River, Pelham Bay Landfill, Edgewater Park and Westchester Creek.

• Offshore breakwaters along Eastchester bay and west of Hart Island.

• Raising bulkheads at Throggs Neck

• Edgewater Park study (part of DCP resilient neighborhoods program)

In spite the fact that the initial SIRR report provides few details to the coastal strategies, it supports the idea of using wetlands and breakwaters to mitigate flooding in the east Bronx. It is expected that the upcoming iteration of the SIRR report to incorporate coastal green infrastructure as a highlighted alternative and examine opportunities for site-specific interventions in greater detail.

4.11. East Bronx Waterfront: NY Rising Community Reconstruction Program

Five water bodies surround the northeast Bronx Community. As a result, over 50% of the area is at flood risk (NY Rising, 2014). Additional to this, sea levels will rise over time, and will very likely increase the incidence of coastal flooding during storms (NPCC, 2013). The NY

Rising Community Reconstruction Program for the East Bronx waterfront is a positive step towards implementing flood mitigation strategies for the community. This program is envisioned towards short-term projects and awards of up to $3 million dollars to initiatives that will address resiliency.

New York State governor Andrew Cuomo initiated this program as a way to empower communities with technical expertise to develop implementable reconstruction plans aiming to build resilient and sustainable communities. Each area is eligible between $3 and $25 million dollars. So far over 45 communities have gone through the process. Parsons Brinkerhoff was the consultant firm providing technical expertise for the East Bronx waterfront study. The development of the plan lasted over 8 months, with the final report and process of selecting funded projects completed in January 2015. It is expected that funded projects will initiate implementation phase during the second semester of 2015.

One of the proposed projects in the area is the Westchester Creek waterfront study; it has been allocated with $200,000, with a total cost estimated at $400,000. Matching funds are expected to come from other government programs or private institutions. Aligned with other planning efforts, the waterfront study offers and opportunity to identify feasible strategies and develop a pathway for their implementation. The first two elements of this study are closely related to the issues discussed in this paper: flood mitigation and water quality. The waterfront study offers an opportunity to validate Coastal Green Infrastructure at Westchester Creek for flood mitigation and water quality improvement.

Figure.31: Potential redevelopment areas at Westchester Creek. Image Credit: Parsons Brinckerhoff

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In collaboration with other planning efforts Westchester Creek waterfront study could provide technical support to validate water quality improvements from CGI and facilitate pilot projects in the area for data collection. Preliminary elements of the Westchester Creek waterfront study are the following:

• Identify and address local areas that are prone to flooding

• Identify areas where new land uses would increase the amount of pervious surface along the creek

• Design future public amenities that incorporate waterfront access and establish a multi-use path to connect existing parkland

• Create a better sense of place by reconnecting neighborhoods to the waterfront and strengthening connections to neighboring areas.

It is imperative to bring attention to the Westchester Creek waterfront study to a broader audience and encourage institutions to provide the additional required funding to initiate technical studies. It is crucial that local government and civic groups become informed about the issues regarding Westchester Creek and improve their ability to engage in an effective planning discussion regarding water quality and flood mitigation.

Figure.32: Rendering of Westchester Creek improvements. Image Credit: Parsons Brinckerhoff Figure.33: Existing Pervious and Impervious surfaces at

Westchester Creek. Data from Pluto V13.1 - Map by M. Negret

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5. COASTAL GREEN INFRASTRUCTURE

5.1. Definition and typologies of Coastal Green Infrastructure

Coastal Green Infrastructure can be defined as designed and engineered landscapes that restore or imitate natural coastal conditions, while providing services to communities and the environment. Such strategies are commonly referred as to living shorelines, ecological engineering, or nature-based features (Mitsch and Jørgensen, 2004).

The Coastal Green Infrastructure Research Plan for New York City is a joined effort between NYS Department of Environmental Conservation and NYC Department of Urban Planning. According to the Plan there are six relevant strategies for the city’s coastal conditions. The following descriptions are literal definitions provided by the plan:

• Constructed Wetlands and upland maritime forests are restored tidal wetlands located at protected and low elevation areas from mean water level. Upland maritime forests are restored forests that can tolerate high salinity and sandy soils and are usually at an elevation above the spring high tide level. Maritime forest may be sheltered behind dunes. The crucial factor for both strategies is vegetation; hence they are grouped in a single category.

• Constructed reefs or breakwaters are artificially constructed reefs and can be emergent or fully submerged below water. They are designed for a variety of uses including wave attenuation, fish habitat and bivalve restoration.

• Constructed breakwater islands are artificial islands that imitate sand bars, wetland islands, or structured rocky habitat and protect coastal areas from wave action.

• Channel shallowing is a strategy of reducing estuary or inlet depths to reduce the inland penetration of storm tides and can be a form of restoration in dredged systems that were historically shallower.

• Ecologically enhanced bulkheads and revetments are hardened shore armoring structures with ecological elements

Figure.34: Living Shoreline in North Carolina. Image credit: www.coastalreview.org/2014/11/challenge-living-shorelines/

Figure.35: Constructed Wetlands. Image source: NYC DCP Urban Waterfront Adaptive Strategies.

Figure.36: Constructed reefs. Image source: NYC DCP Urban Waterfront Adaptive Strategies.

Figure.37: Constructed breakwater islands. Image source: NYC DCP Urban Waterfront Adaptive Strategies.

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• Living shorelines, specifically sill-type, are soft stabilization treatments that require sediment fill, sill and planting. Living shorelines can be considered a combination of several of the previous strategies. (NYS DEC et al, 2015).

Traditional costal protection approaches such as bulkheads and revetments, do not provide ecological benefits or recreational functions, and due to their costly maintenance are not considered resilient or sustainable (van Slobbe et al. 2013). On the contrary, Coastal Green Infrastructure has the potential of providing multiple services at much lower maintenance cost, the most widely accepted functions are:

• Reducing coastal erosion

• Mitigating storm surge, wave actions and flooding associated with coastal storms (hurricanes and northeasters)

• Nutrient removal and water filtration

• Creating habitat for aquatic, terrestrial and avian species

Protective functions and ecological services will vary significantly among each Coastal Green Infrastructure typology. New York City Coastal Green Infrastructure Research Plan lists and classifies coastal hazard mitigation and ecological benefits from each of the six strategies. The classifications are summarized in the following table (figure 38).

5.2. Coastal Flood MitigationResearch from academic and government entities are

investigating the complexity on how waves and surge interact with natural coastal landforms (NYS DEC et al, 2015). In spite of the dynamic state of science related to the flood mitigation capabilities of natural defense systems, research provides strong evidence that coastal ecosystems perform protective functions by reducing wave action and buffering storm surge, while providing ecological services (Day et al. 2007).

Wave action reduction can be measured using the Gauckler-Manning coefficient, a flow formula used to estimate the average velocity of liquid flow. At tidal wetlands, the manning coefficient depends on surface roughness and vegetative drag of the wetland species. Vegetation, bivalve species, sediments and breakwaters can significantly reduce flow velocity by increasing surface roughness. Moreover, to predict velocity reduction of constructed wetlands, it is required to estimate vegetal drag of predominant species in the environment (J. Chapman, 2014). Vegetal drag is a coefficient used to estimate the level of rigidity or flexibility (biomechanical characterization) of a particular wetland species. Accurate identification of vegetal drag will allow to appropriately selecting species that will perform better under certain flow conditions. In other words, Coastal Green Infrastructure increases surface friction that reduces wave action. Such reduction rates depend on wetland vegetation and materials with biomechanical characteristics that dissipate energy under storm conditions.

Additional factors that determine wave attenuation from restored wetlands are vegetation density, maturity, wetland area and seasonality (NYS DEC et al, 2015). A dense, large and established wetland will be much more effective in reducing wave action than a less populated, small and recently restored wetland. Constructed wetlands tend to reach ecological maturity between 5-10 years (L. France, 2003), thus having improved chances

Figure.39: Living Shorelines. Image source: NYC DCP Urban Waterfront Adaptive Strategies.

Figure.38: Channel shallowing. Image source: NYC DCP Urban Waterfront Adaptive Strategies.

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Figure.40: Benefits table per strategy. Image source: NYC Coastal Green Infrastructure Research Plan

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of withstanding and reducing wave action during storm events. On the contrary, wetlands that have not been fully established are more vulnerable to coastal erosion and vegetation uprooting during storm events. Additional to this, seasonality plays an important role in determining wave attenuation from wetland populations. Northeasters usually occur during winter months, a season in which surface roughness and vegetative drag in wetlands is expected to be lower. Because of this, it can be assumed that Coastal Green Infrastructure will be less effective in mitigating flooding from northeasters. On the other hand, during the growing season (early spring through fall) surface roughness and vegetative drag is expected to increase due to leaf presence and larger surface area, hence having greater flood mitigation capacity. Since New York City’s highest probability of flood risk occurs between August and October during hurricane season, it can be argued that Coastal Green Infrastructure will provide the maximum expected protection during the most critical time frame. Further studies are expected to be conducted through the Coastal Green Infrastructure research plan and help determine biomechanical characteristics under different factors, including density, maturity and seasonality.

The infamous Phragmites australis, a non-native plant that is aggressively invading large areas of wetlands in the U.S, presents an interesting case of ecological tradeoff. With mixed results, restoration efforts in New York City have traditionally focused in eliminating invasive species and replacing them with native vegetation. However, the invasive reed plays an important role (and most likely will continue to do so) in providing ecosystem services such as: preventing erosion, wave dissipation and water purification. Due to its rigidity and population density, Phragmites could have a higher potential to

reduce wave action than native species Cordgrass. Moreover, recent studies have documented important ecosystem services of Phragmites in habitat creation (NYS DEC et al, 2015). It becomes crucial that future studies focus on measuring biomechanical characteristics, as well as other ecosystems services provided by Phragmites in order to reach a scientific conclusion that supports wetland restoration strategies.

Since the devastating effects of recent flood events: the tsunami in the Indian Ocean (2004), Hurricane Katrina (2005) and Hurricane Wilma (2005) in the Gulf of Mexico and Hurricane Sandy (2012) in the Northern Atlantic, research in this field has been active, releasing many numerical based studies. While it is widely accepted that Coastal Green Infrastructure can slow and reduce storm surges, protecting communities and infrastructure from coastal flooding, further research is required to determine expected performance in New York City. In contrast to the available documentation for water quality improvement provided by nature-based features, studies focusing on coastal hazard mitigation by green infrastructure still have not been able to provide numerical models specific to the area. Significant knowledge gaps and performance guidelines that accurately predict performance of wave reduction and storm surge mitigation are still not in place for wide scale implementation in New York City (NYS DEC et al, 2015).

The Coastal Green Infrastructure Research Plan for New York City is a positive step towards developing flow models that accurately represent vegetative mechanical characteristics of the area. Through laboratory experimentation, pilot projects and field research it is

Figure.42: Phragmites covering the landscape at Westchester Creek near Schuylerville. Photo by M. Negret

Figure.41: Vegetative Drag Lab test. Image source: www.tu-braunschweig.de/lwi/wasserb

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Constructed Wetlands Guidelines

Geometry for ecological productivityCreating irregular shorelines can increase their length by up to 10-30 p ercent per unit of wetland area. Maximizing shoreline lenght will provide benefits to wildlife by increasing nesting and resting areas and for water quality by increasing contact sites for contaminant removal (L. France, 2003).

Depth and WaterflowDeep zones should be arranged perpendicular to flow direction. Intersections o f shallow and deep w ater a reas will i ncrease t he e fficiency o f contaminant removal and attractiveness of wildlife. (L. France, 2003).

poor good

water flow

wildlifehabitat

shallow marsh deep water zones

contaminantremoval

ww

Planting ZonesHigher biodiversity throught all planting zones can translate into increased ecological productivity, reducing coastal hazards and improving water quality (L. France, 2003).

Growth formsFive major growth forms of vegetation are available for use in created wetlands in relation to their suitability for particular planting zones (L. France, 2003).

woody

emergent

submergedfloating

anchoredfree

floating

shrub wetland

wet meadow

shallow marsh

deep marsh

open water

forested wetland

Figure.43: Geometry and depths for Constructed Wetlands. Source: L. France Wetland Design, redrawn by M. Negret

Figure.44: Bioiversity at planting zones and growth forms. Source: L. France Wetland Design, redrawn by M. Negret

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expected that knowledge gaps will be resolved and predictive models developed. Under such scenario, current regulatory framework related to wetland restoration should be updated, allowing for large-scale implementation of Coastal Green Infrastructure in New York City.

5.3. Pollutant Removal and Water Filtration Performance Variability

Wetlands help remove or transform pollutants and sediments by acting as natural filters. Wetlands help improve water quality by removing nutrients, biochemical oxygen demand, suspended solids, metals and pathogens (EPA, 2013). Constructed wetlands recreate such filtration capacity and improve water quality. Perhaps the best-known example of a constructed wetland is Frederick Olmstead’s Back Bay Fens Park in Boston, Massachusetts. The park was completed in 1900 and was designed to alleviate health risks from sewage discharges and mitigate seasonal flooding. Ever since then, hundreds of wetlands around the country have been restored and created to improve water quality (France, 2003).

A study conducted by professor L. France at Harvard School of Design, summarized 226 input-output differences in bacteria and chemical concentrations from studies on created wetlands. Three quarters of all analyses indicated that contaminant removal performances of 75% or greater is possible in all pollutant categories. However, considerable variability exists among the removal efficacy for each pollutant category (France, 2003). Bacteria removal has the highest efficiency rate, with over 60% of analyzed studies indicating removal performances over 90%. The NYS DEC determines water body classification and usage based in the amount of pathogens found in water (fecal coliform and enterococci bacteria). Based on the documented removal rates by wetlands and the water quality indicators used by DEC, constructed wetlands emerge as a viable alternative to improve water quality at Westchester Creek.

In order to achieve such removal rates, it is paramount that transport ratio of time and distance are evaluated to estimate removal effectiveness of the constructed wetland. The same study conducted by L. France, analyzed information from 52 surveys of changes in the temporal and spatial concentration of chemicals during transit through treatment wetlands. As a rule of thumb, longer distances and time frames of contaminated water transported through wetlands result in higher removal rates. For retention ponds or freshwater wetlands filtering

stormwater runoff, the recommended transport time for optimal removal effectiveness of bacteria is 10-15 days of continuous water flow. Moreover, the recommended transport distance to reach optimal bacteria removal is 330 linear feet (L. France, 2003). Based on the previous guidelines it can be calculated that the ideal flow rate for maximum pathogen removal capacity is approximately 1.15 feet per hour. This metric is especially important to determine scale and location of potential retention ponds or freshwater wetlands.

Landform alterations can provide conditions that augment transport time and distance, reaching recommended parameters. Creating irregular shorelines can increase their length by up to 10-30 percent per unit of wetland area. Maximizing shoreline length will provide benefits to wildlife by increasing nesting and resting areas and for water quality by augmenting contact sites for contaminant removal. A second alternative to increase treatment distance is by modifying the depth and waterflow of the wetland. Deep zones should be arranged perpendicular to flow direction, intersections of shallow and deep-water areas will increase the efficiency of contaminant removal and attractiveness to wildlife (L. France, 2003). The following diagrams illustrate landform alterations that increase length per unit of wetland area and maximize waterflow distance.

Additional to the treatment capacity of freshwater wetlands, bivalve species offer excellent water filtering volume at saltmarshes. Shellfish such as mussels and oysters feed from plankton and incorporate into their shells and tissue nutrients that are in excess in the urban waters. As mentioned previously, the largest sources of such excessive nutrients at Westchester

Figure.45: Cordgrass and Ribbed Mussels at Westchester Creek. Photo by M. Negret

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Future CSO discharge option A: 181 MGY

Stormwater discharge: 327 MGY

Mussel filtration4300 sqf : 693 MGY

Future CSO discharge option B: 97 MGY

Transport Time EffectivenessTo ensure effective removal of most pathogens, water should take 10-15 days t o transit through t reatment w etlands ( L. France, 2003).

bacteria

05 10 15 20

phosporus

BOD

time (days) to removal plateau

nitrogen

suspendedsediments

bacteria

06 5 130 195 260 330

phosporus

BOD

Distance from inflow (ft) to removal plateau

nitrogen

suspendedsediments

color

Figure.46: Expected pollutant removal performances by constructed Wetlands. Data by L. France

bacteria

Proportionof studies

>60%

50-60%

30-50%

<30%

metals

organics

phosporus

BOD

nitrogen

Poor<50%

Moderate50-75%

Good75-90%

V. Good>90%

suspendedsediments

Figure.47: Ribbed mussel water filtration capacity. Data by NOAA diagram by M. Negret

Figure.48: Transport time effectiveness for pollutant removal by constructed Wetlands. Data by L. France

Figure.49: Transport time effectiveness for pollutant removal by constructed Wetlands. Data by L. France

Wetland Treatment Capacity

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creek are stormwater runoff and combined sewer discharges. By harvesting the bivalves, the excess nutrients would also be removed from the environment, thus improving water quality; this process is defined as Bioextraction (LISS, 2013). Bioextraction use with shellfish species could be an additional strategy to improve water quality at Westchester Creek. However, Bioextraction with shellfish harvesting is not considered as a component of a coastal green infrastructure strategy. Studies conducted in the Bronx River estuary are relevant since they provide insight into implementing ecologically enhanced revetments and breakwaters with bivalve species.

Between 2012 and 2013 the study conducted near Hunt’s point in the East River/Bronx River estuary documented the filtering capacity of Geukensia demissa  (ribbed mussels). The study consisted on harvesting ribbed mussels from Jamaica bay, seeding them to pegged ropes and then attaching them to a 20 x 20 feet raft boat located in the Bronx river estuary. The metrics indicated that one acre of surface area of a ribbed mussel culture operation would be expected to filter 19 million gallons per day, and remove 616 kg per day of suspended particulate matter (LISS, 2013). According to this, an individual mussel with an average weight of 7.5 grams and permanently submerged should filter 1.14 gallons per day and remove 35.3 grams of suspended particulate matter.

Because humans commonly consume shellfish, especially oysters, a valid concern about using this bioextraction method would be the potential health risk of harvesting contaminated specimens that might be introduced illegally into the food market. However, in the case of ribbed mussels such risk can be discarded based on the fact that humans do not consume their meat due to its poor taste. The appropriate use for the harvested mussels is a key component for large-scale implementation of bioextraction. The Alternative Feeds Initiative for aquaculture, a program funded by The National Oceanic and Atmospheric Administration (NOAA), is identifying the potential use for the harvested mussels as fish feed. Other potential uses for harvested mussels include chicken feed and compost (LISS, 2013).

Shellfish seeded on coastal green infrastructure (ecologically enhanced revetments and breakwaters) will not be permanently submerged and exposed to tidal action. Because of this, it is expected for bivalve species in this environment to have lower filtration capacity than the documented volumes from the Bronx River study. Nevertheless, documented filtering capacity from the

pilot project can be used as a reference point. For the purposes of this paper it will be assumed that the filtering capacity of ribbed mussels on ecologically enhanced revetments and breakwaters to be 50% less than the pilot project: an individual mussel with an average weight of 7.5 grams and exposed to tidal action is assumed to filter 0.6 gallons per day and remove 17 grams of suspended particulate matter. By seeding mussels in breakwaters and shorelines at a large Coastal Green Infrastructure installation, hundreds of kg of particulate matter will be removed and millions of gallons of water filtered per day. Under this scenario it can be expected that Ribbed mussel tissue will most likely return safely to the food chain, serving as feed for fishes and aquatic birds.

Since grey infrastructure strategies for water quality improvement at Westchester Creek are no longer considered to be cost effective, examining potential water quality improvements from nature based features becomes crucial. By scaling coastal green infrastructure and its filtration capacity, water quality at Westchester Creek will significantly improve. Through strategically placed bioswales, treatment wetlands, marshlands, and bivalve reefs, pathogens in the waterbody will decrease, potentially reaching criteria for primary contact. It is paramount that future waterfront studies for Westchester Creek include within their research agenda water quality improvement from coastal green infrastructure.

5.4. Case studies in the region and around the world

The concept of using nature based features at coastal areas for erosion control, flood mitigation and water quality improvement has been implemented since the late 19th century. In the face of increasing flood risk and water quality degradation, coastal green infrastructure is beginning to emerge as a viable alternative to resolve many of these challenges. Coastal Green Infrastructure is being implemented at large scale operations, ranging from China to the northeast coast of the United States.

Many consider the Back Bay Fens of the Muddy River in Boston, designed by Frederick Law Olmstead, as the worlds most famous and beautiful constructed wetland created for urban water treatment. As part of the Emerald Necklace, Back Bay Fens Parks is also part of the oldest park system in the United States. Olmstead’s plan focused on restoring a pre-colonial saltmarsh, mitigating potentially dangerous seasonal flooding, and alleviating health risks from sewage discharges. Through an ingenious linear park his vision would provide recreation

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opportunities and link the historic city with newer outlying neighborhoods (France, 2003). Because of increased urban development, the project currently does not provide the same functions it did over a century ago. However, the basic principles laid by Olmstead, are still valid to address modern challenges.

The states of Rhode Island, Maryland, Virginia and North Carolina have successfully updated policy regarding wetland restoration and are promoting the protection of shorelines with coastal green infrastructure. Perhaps Virginia stands out as being the most active state in promoting coastal green infrastructure. Through the Virginia Coastal Zone Management Program, the Virginia Institute of Marine Science has published a series of living shoreline design guidelines (VIMS, 2010). Moreover, the institute has promoted and hosted summits aiming to improve knowledge and create consensus regarding tidal wetlands restoration and construction. The report highlights over a dozen successful case studies of Living Shoreline implementation at Chesapeake Bay, Virginia. Case studies describe site sitting, design and construction elements and documented performance from projects built since the early 1980’s and going as recently into 2008. Projects described are categorized into marsh management, marsh revetment projects, sills and breakwaters (VIMS, 2010).

Turenscape is one of the largest architectural and landscape architectural firms in China. The firm is recognized for designing social and environmentally sound landscapes and it has received hundreds of awards, including dozens by the American Society of Landscape Architects. It can be argued that Turenscape is a major international player in this generation of urban design. Within their portfolio, dozens of projects are

highlighted for utilizing constructed wetlands and other variations of coastal green infrastructure to improve water quality and mitigate flooding. The rehabilitation of the Shuicheng River stands out as project that effectively implemented a series of interconnected wetland parks to improve ecological services. By utilizing landscape approaches at both macro and micro scales, the ecological, recreational and social value of the Shuicheng River has been revitalized and upgraded. The wetland system, successfully improved water quality, and mitigates both erosion and flooding during the rainy season.

As indicated by the Coastal Green Infrastructure Research Plan, many specific conditions relevant to New York City still require further analysis. However, the successful implementation of coastal green infrastructure throughout the region and world provides strong evidence to champion this strategy in New York City. While it is true that existing knowledge gaps should be resolved, the similarity of the environmental challenges stressing Westchester Creek and those at Chesapeake Bay and

Figure.50: Back Bay Fens Wetland Park in Boston Massachusetts. Photo by M. Negret

Figure.51: Living Shoreline at Chesapeake Bay, Virginia. Image credit: VIMS Guidelines

Figure.52: Shuicheng River Wetland Park in China. Photo source: Turenscape Architecture

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the Shuicheng River, give indication of high success potential for living shorelines and other varieties of Coastal Green Infrastructure.

5.5. Scaling Coastal Green Infrastructure at Westchester Creek

Shoreline conditions, bathymetry, land use and lot ownership at Westchester Creek waterfront, suggest that scaling Coastal Green Infrastructure to be a feasible solution. By restoring an area between 150 and 200 acres into tidal wetlands, forests and breakwaters, ecosystem services will be substantially increased; not only protecting the area from coastal flooding, but also improving water quality.

Based on the Urban Waterfront Adaptive Strategies report by DCP, required capital costs for scaling Coastal Green Infrastructure to this magnitude would range between $120 and $220 million dollars. Even tough it is a substantial amount; it comes much lower than traditional coastal protection strategies and has the added value of mitigating the risks from several hazards. As a comparison, building levees and dikes all around Westchester Creek would have a cost between $130 million and $1,5 billion dollars, a very unlikely capital project to take place in the following decades. Additional to this, the proposed grey infrastructure projects by DEP in the CSO LTCP come to a range between $137 and $530 million dollars, another unlikely capital project to occur in the following decade. By pairing two risks and considering a single solution that addresses them simultaneously, Coastal Green Infrastructure emerges as strong and reasonable alternative.

Most of the marshland restoration efforts can be achieved at the lower and widest section of the creek, with relatively shallow depths between 5 – 10 feet below

median water level. By using channeling shallowing strategies in those locations, area for marshland creation could reach between 110 and 140 acres. Furthermore, breakwaters should be implemented to reduce wave action from fetch distances greater than ½ mile and reduce coastal erosion. Estimated area for breakwaters ranges from 10 – 20 acres, stretching approximately 5 linear miles and located between 100 feet and 300 feet from the shoreline. Econcrete units or equivalent material with low ph levels and textured surfaces that attract aquatic life should be used as main building material to create living breakwaters. Freshwater wetlands, built inland could reach between 15 to 20 acres and a linear distance of approximately 6 miles. Under this scenario up to 200 acres of coastal green infrastructure would have been created. Finally, remaining shallow areas in the lower section of the creek could be left for future development of tidal mudflats, with approximately 110 acres suitable for this condition.

Westchester creek waterfront is characterized by having a considerable amount of open space, such as Pugsley Creek and Ferry Point Park. For those areas, larger concentrations of Coastal Green Infrastructure are expected to be feasible, having average distances from shoreline to breakwaters between 200 and 300 feet. Additionally, most of the highland forest areas and freshwaters can be located where open space exists. In general terms, the expected condition for most of the east bank section and Ferry Point Park is illustrated in the following section drawing.

In other areas, existing urban development limit available space for highland forests and freshwater wetlands, this is especially true along most of the west bank section of Westchester Creek. In replacement of freshwater wetlands, bioswales and other measures

Figure.53: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies

Figure.54: Ferry Point Waterfront Park. Photo by M. Negret

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Figure.55: Proposed Coastal Green Infrastructure at Westchester Creek. Map by Marcel Negret

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MHW + SLR = 5.84'MHW = 3.34'

MLW = -3.83'MSL = -0.22'

LIVINGBREAKWATERS

LOWMARSH

HIGHMARSH

RANGES BETWEEN 1,200ʼ - 400ʼ

STORM SURGE

VEGETAL DRAG

POLLUTANT REMOVAL

STORM RUN OFF

INFILTRATION

FRESHWATERWETLAND

OPENSPACE

HIGHLANDFOREST

TIDALMUTFLATS

Westchester Creek East Bank Typical SectionProposed scale of Coastal Green Infrastructure

Open space, bathymetry and ecological conditions a llow for a variety o f Coastal G reen Infrastructure interventions. O ptions r ange f rom highland f orest r estoration, f reshwater w etland construction for runoff capture, channel shallowing for marsh creation and breakwaters with ecological features.

Figure.56: Proposed Coastal Green Infrastructure at Westchester Creek East Bank. Section drawing by M. Negret

Figure.57: Proposed Coastal Green Infrastructure at Westchester Creek East Bank. Map by M. Negret

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MHW + SLR = 5.84'MHW = 3.34'

MLW = -3.83'MSL = -0.22'

STORM SURGE

LIVINGBREAKWATERS

LOWMARSH

HIGHMARSH

BIOSWALE OPENSPACE

FLOODWALL

TIDALMUTFLATS

RANGES BETWEEN 600ʼ - 200ʼ

VEGETAL DRAGPOLLUTANT REMOVAL

INFILTRATION

Westchester Creek West Bank Typical SectionProposed scale of Coastal Green Infrastructure

Figure.58: Proposed Coastal Green Infrastructure at Westchester Creek West Bank. Section drawing by M. Negret

Figure.59: Proposed Coastal Green Infrastructure at Westchester Creek West Bank. Map by M. Negret

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Figure.60: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies

Figure.61: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies using low range estimates

Figure.62: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies using high range estimates

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could be implemented to reduce stormwater runoff. Moreover, additional protection measures such as deployable floodwalls might be feasible. In these sections it can be expected that distances from shoreline to breakwaters range between 50 and 150 feet, such conditions are represented in the following section drawing.

5.6. Shallowing and dredged sediments usage for marshland creation

In a report by the Gaia Institute from 1998, the concept of using dredged material for marshland creation at the East Bronx was introduced. In order to maintain navigability for larger boats at the Royal Marina, dredging operations where being required. The plan proposed using the dredge sediments for salt marsh creation along Pelham Bay Landfill, which at the moment was discharging leachates into Eastchester Bay. By using dredged materials for ecological restoration projects and maintaining local scale, water based industries would be then benefited by lowering operations costs, as well as having improved water quality and increased fisheries production (Mankiewicz, 1998).

A similar situation is presented today at Westchester Creek, navigability of the channel has been compromised. Some local residents argue that the DEP should be responsible for restoring channel depth. The rationale used to support this is that sediments from the sewer discharges have significantly accumulated and altered the bathymetry. However, further analysis should be concluded to validate the previous hypothesis. Nevertheless, the use of locally dredged sediments for shallowing areas along the navigation channel of

Westchester Creek, provides tremendous opportunities, not only for wetland restoration but for economic incentive.

Future studies, including the NY Rising Westchester Creek Waterfront study, should explore and validate the idea of using local dredged sediments for marshland creation along areas with depths between 5 and 8 feet below median water level. By decreasing the depth of these areas to a few feet, hundreds of acres would become suitable for implementing Coastal Green Infrastructure.

5.7. Coastal Green Infrastructure as a research factor for upcoming studies

As discussed during the planning framework chapter, several waterfront planning and water management processes relevant to Westchester Creek have been recently initiated. The most relevant planning efforts are:

• Long term control plan for combined sewer overflows for Westchester Creek. Developed by NYC Department of Environmental Protection. The plan has been submitted but not approved by the Department of Environmental Conservation.

• Waterfront study for Westchester Creek, proposed through the NY Rising Community Reconstruction Program. The study aims to identify mitigation flood alternatives and strategies to improve waterfront access. The study has been allocated with $200,000, but is estimated to cost $400,000. The plan is yet to be developed, and as by May of 2015 the scope of the study remains somewhat flexible.

Figure.63: Dredging operation. Image credit: Union Dredgers

Figure.64: Tidal Wetlands at Pugsley Creek. Photo by M. Negret

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• The Coastal Green Infrastructure Research Plan for New York City is a joined effort between the Department of City Planning and the Department of Environmental Conservation. The plan is designed to advance the understanding of the costs and benefits of CGI and facilitate its implementation in NYC.

The outcomes of such plans will determine water quality improvements and developed strategies to mitigate flooding. However, these efforts are isolated from each other. Coastal Green Infrastructure could be the element that brings cohesion among these planning efforts. One possible scenario on how to integrate them would be having the partially funded NY Rising Waterfront study provide technical support to help validate Coastal Green Infrastructure implementation at Westchester Creek. Moreover, in the face of the Long Term Control Plan inability to propose cost effective strategies that reach desirable water quality criteria, the department of environmental protection should provide further assistance and resources to the waterfront study, adding water quality as a research factor. This new adaptation of the NY Rising waterfront study, could even facilitate a pilot project through the Coastal Green Infrastructure research plan for New York City. Under this scenario, the new waterfront study will be aligned with the research agenda for Coastal Green Infrastructure in NYC and able to determine the feasibility for implementation at Westchester Creek.

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6. CONCLUSION

Based on the environmental conditions of Westchester Creek, increasing the existing 42 acres of Coastal Green Infrastructure into approximately 250 acres is likely to be feasible and cost effective. The use of local dredged sediments for channel shallowing and marshland creation is highly recommended for reaching this scale of Coastal Green Infrastructure. Under such scenario water quality will significantly improve, potentially reaching criteria for primary contact. Moreover, the 250 acres of Coastal Green Infrastructure will substantially reduce coastal flooding from sea level rise and future storm events. Additional to this, by encouraging an integration of the existing planning efforts related to Westchester Creek, feasibility can be accurately be determined and chances of large-scale implementation of Coastal Green Infrastructure will substantially increase.

Accomplishing such goals will be a challenging task. As with most major infrastructural projects, political climate and financial limitations will often override long-term efforts. In order to maintain and strengthen the self-sufficient community that defines the East Bronx it is crucial that engaged citizens continue to participate in resiliency planning efforts, encouraging decision makers and elected officials to take action towards an environmentally sound and resilient Westchester Creek.

Figure.65: Westchester Creek from Ferry Point Park. Photo by M. Negret

7. REFERENCES

• New York City Department of Environmental Protection, NYC DEP. 2014. Combined Sewer Outfall Long Term Control Plan for Westchester Creek.

• New York State Department of Environmental Conservation, NYS DEC. 2011. The Atlantic Ocean/Long Island Sound basin Waterbody inventory and priority waterbodies list.

• The New York Times, Lisa W. Foderaro. 2015. Luxury Public Golf Course Run by Trump Opens on Former Bronx Dump.

• New York City Department Of City Planning, NYC DCP. 2013. Waterfront Revitalization Program.

• John E. Virden. 2005. Old Westchester: The Bronx County Historical Society Journal Volume XLII. Pages 100 – 101.

• New York City Mayor’s Office. 2012. PlaNYC, New York City Wetlands Strategy. Pages 10 – 33.

• A. Randall Hughes, Althea F. P. Moore and Michael F. Piehler. 2013. Independent and interactive effects of two facilitators on their habitat-providing host plant, Spartina alterniflora” Pages 1-3.

• Andrew H. Altieri, Brian R. Silliman and Mark D. Bertness. 2006. Hierarchical Organization via a Facilitation Cascade in Intertidal Cordgrass Bed Communities. Pages 1-2.

• Peter Del Tredici. 2010. Wild Urban Plants of the Northeast. Pages 17 – 18.

• Environmental Protection Agency (EPA) Region 5 Wetlands Supplement. 2013. Incorporating Wetlands into Watershed Planning.

• Keith Beckmann, LTCP Program Director, Bureau of Wastewater Treatment. 2014. DEP response letter to DEC regarding Westchester Creek CSO LTCP.

• NY Rising Community Reconstruction Committee. 2014. East Bronx Waterfront Plan

• D.M. Bilkovi and M.M. Mitchell. 2013. Ecological tradeoffs of stabilized salt marshes as a shoreline protection strategy: Effects of artificial structures on macrobenthic assemblages. Pages 2 -3.

• Day, J. W. J., D. F. Boesch, E. J. Clairain, G. P. Kemp, S. B. Laska, W. J. Mitsch, K. Orth, H. Mashriqui, D. J. Reed, L. Shabman, C. A. Simenstad, B. J. Streever, R. R. Twilley, C. C. Watson, J. T. Wells and D. F. Whigham. 2007. Restoration of the mississippi delta: Lessons from hurricanes Katrina and rita” Pages 1679-1684.

• Van Slobbe, E., H. J. de Vriend, S. Aarninkhof, K. Lulofs, M. de Vries and P. Dircke. 2013. Building with nature: In search of resilient storm surge protection strategies, Natural Hazards” Pages 1461-1480.

• John A. Chapman. 2014. Selection of Vegetation and Flexible Vegetal Drag Coefficients for Erosion Control in Lacustrine Wave Environments. Pages 31-55.

• Robert L. France. 2003. Wetland Design: Principles and Practices for Landscape Architects and Land-Use Planners” Pages 15-80.

• Long Island Sound Study. Ribbed Mussel Pilot Study in the Bronx River, New York City. 2013. Mussel Bioextraction Final Report. Pages 1-4.

• New York State Department of Environmental Conservation, NYS DEC and The New England Interstate Water Pollution Control Commission NEIWPCC. 2015. Coastal Green Infrastructure Research Plan for New York City. Pages 15 – 93.

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• Virginia Institute of Marine Science. 2010. Living Shoreline Design Guidelines for Shore Protection in Virginia’s Estuarine Environments. Pages 23 – 32.

• New York City Department of City Planning, NYC DCP. 2013. Urban Waterfront Adaptive Strategies. Pages 76 - 103.

• Paul Mankiewicz. 1998. Beneficial Use of Dredge Materials for the Improvement and enhancement of Eastchester Bay Wetlands and the Water Based Economy of the Eastern Bronx. Pages 7 – 14.

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8. LIST OF FIGURESFigure.1: Westcheter Creek. Photo by M. Negret 4Figure.2: Historical Map of Westchester and Pelham Towns. 5Figure.3: Poor water quality at Westchester Creek 6Figure.4: Coastal flood risk in the east Bronx 7Figure.5: Project clients: East Bronx Coastal Working Group and Bronx Community Board 10 8Figure.6: Westchester Creek study area 9Figure.7: Geotagged photos from first hand analysis. Image source: www.instagram.com/east_bronx_coast/ 10Figure.8: Digital interface of WCCW Plannning Tool. Image source: www.arcg.is/1ySmSG5 10Figure.9: Westchester Creek historical watershed and wetlands. Map by M. Negret 13Figure.10: Westchester Creek existing watershed and outfalls. Map by M. Negret 14Figure.11: Westchester creek NYS DEC designated tidal wetlands. Map by M. Negret 16Figure.12: Spartina Alterniflora, Honey Locust and Ailanthus Altissima at Westchester creek. Photos by M. Negret 17Figure.13: Phragmites Australis and Ribbed Mussels at Westchester creek tidal wetlands. Photos by M. Negret 17Figure.14: Cordgrass Spartina Alterniflora at Westchester creek tidal wetlands. Photos by M. Negret 17Figure.15: Population density per census track within Westchester Creek watershed. Map by M. Negret 19Figure.16: Land Use at Westchester Creek. Map by M. Negret 20Figure.17: Lot ownership at Westchester Creek. Map by M. Negret 21Figure.18: Shoreline typologies at Westchester Creek. Categories by Urban Waterfront Strategies. Diagram by M. Negret 22Figure.19: Topography and bathymetry at Westchester Creek. Map by M. Negret 23Figure.20: East Bronx Coastal Zones. Map by NYC DCP Waterfront revitalization Program 24Figure.21: Special Natural Waterfront Areas in the Bronx. Map by NYC DCP Waterfront revitalization Program 25Figure.22: Kayaking activies at Ferry Point Park in Westchester Creek. Photo Credit: Dorothea Poggi 26Figure.23: Cost benefit chart for each CSO mitigation plan at Westchester Creek. Data from DEP, Diagram by M. Negret 27Figure.24: Current outfall discharges at Westchester Creek. Map by M. Negret 28Figure.25: Outfall discharges after WWFP implementation at Westchester Creek. Map by M. Negret 29Figure.26: Outfall discharges after LTCP implementation at Westchester Creek. Map by M. Negret 30Figure.27: Proposed deep inline storage tunnel for Westchester Creek. Image source: DEP LTCP 32Figure.28: Green Roof at Einstein College of Medicine within Westchester Creek watershed. Photo credit: Gaia Institute 32Figure.29: 100 year floodplains + projected sea level rise by year 2050. Map by Marcel Negret 34Figure.30: 100 year floodplains + projected sea level rise by year 2050. Map by Marcel Negret 35Figure.31: Potential redevelopment areas at Westchester Creek. Image Credit: Parsons Brinckerhoff 36Figure.32: Rendering of Westchester Creek improvements. Image Credit: Parsons Brinckerhoff 37Figure.33: Existing Pervious and Impervious surfaces at Westchester Creek. Data from Pluto V13.1 - Map by M. Negret 37Figure.34: Living Shoreline in North Carolina. Image credit: www.coastalreview.org/2014/11/challenge-living-shorelines/ 38Figure.35: Constructed Wetlands. Image source: NYC DCP Urban Waterfront Adaptive Strategies. 38Figure.36: Constructed reefs. Image source: NYC DCP Urban Waterfront Adaptive Strategies. 38Figure.37: Constructed breakwater islands. Image source: NYC DCP Urban Waterfront Adaptive Strategies. 38Figure.38: Channel shallowing. Image source: NYC DCP Urban Waterfront Adaptive Strategies. 39Figure.39: Living Shorelines. Image source: NYC DCP Urban Waterfront Adaptive Strategies. 39Figure.40: Benefits table per strategy. Image source: NYC Coastal Green Infrastructure Research Plan 40Figure.41: Vegetative Drag Lab test. Image source: www.tu-braunschweig.de/lwi/wasserb 41Figure.42: Phragmites covering the landscape at Westchester Creek near Schuylerville. Photo by M. Negret 41Figure.43: Geometry and depths for Constructed Wetlands. Source: L. France Wetland Design, redrawn by M. Negret 42Figure.44: Bioiversity at planting zones and growth forms. Source: L. France Wetland Design, redrawn by M. Negret 42Figure.45: Cordgrass and Ribbed Mussels at Westchester Creek. Photo by M. Negret 43Figure.46: Expected pollutant removal performances by constructed Wetlands. Data by L. France 44Figure.47: Ribbed mussel water filtration capacity. Data by NOAA diagram by M. Negret 44Figure.48: Transport time effectiveness for pollutant removal by constructed Wetlands. Data by L. France 44Figure.49: Transport time effectiveness for pollutant removal by constructed Wetlands. Data by L. France 44Figure.50: Back Bay Fens Wetland Park in Boston Massachusetts. Photo by M. Negret 46Figure.51: Living Shoreline at Chesapeake Bay, Virginia. Image credit: VIMS Guidelines 46Figure.52: Shuicheng River Wetland Park in China. Photo source: Turenscape Architecture 46Figure.53: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies 47Figure.54: Ferry Point Waterfront Park. Photo by M. Negret 47Figure.55: Proposed Coastal Green Infrastructure at Westchester Creek. Map by Marcel Negret 48

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Figure.56: Proposed Coastal Green Infrastructure at Westchester Creek East Bank. Section drawing by M. Negret 49Figure.57: Proposed Coastal Green Infrastructure at Westchester Creek East Bank. Map by M. Negret 49Figure.58: Proposed Coastal Green Infrastructure at Westchester Creek West Bank. Section drawing by M. Negret 50Figure.59: Proposed Coastal Green Infrastructure at Westchester Creek West Bank. Map by M. Negret 50Figure.60: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies 51Figure.61: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies using low range estimates 51Figure.62: Cost benefit comparisson chart. Data from NYC DCP Urban waterfront strategies using high range estimates 51Figure.63: Dredging operation. Image credit: Union Dredgers 52Figure.64: Tidal Wetlands at Pugsley Creek. Photo by M. Negret 52Figure.65: Westchester Creek from Ferry Point Park. Photo by M. Negret 54

Coastal Green Infrastructure for Westchester CreekMarcel NegretM.S. Candidate In Urban Environmental Systems Management