Map of proposed Right-of-Way Green Infrastructure Sites

Map of proposed right-of-way Green Infrastructure sites within green corridors, with 10-foot buffer highlight around each site for visibility.

In the above map, also note the blue rectangle shown just south of 111th Street. This is the sample “parking lot infiltration swale” modeled by the studio based on runoff calculations for a 1″ rain event. Approximately 90% of rain events in New York City are 1″ or below according to estimates from the NYC Department of Environmental Protection.

There a numerous mid-to-large parking lots in the study area that are mapped by NYC DOITT, belonging to city agencies such as NYCHA or to private entities. This parking lot between 110th Street and 111th Street happens to be one of the largest, at 71,492 square feet or nearly 1.64 acres. It is used by Con Edison, and provides a wonderful opportunity to capture runoff from a single large paved area that would otherwise flow directly into the combined sewershed of WI-024 and overflow into the Harlem River during all significant rain events. The map below shows the suggested area of the infiltration bioswale for this non-right-of-way area, to capture all runoff from the parking lot for rain events of 1″ and below. This would complement the suggested green infrastructure sites along the sidewalk and roadbed of 111th Street.


Map of sewersheds and combined sewer lines in East Harlem Study Area

The map below shows the individual Combined Sewer sewersheds (in purple- click for designation) within the study area, overlaid with the individual combined sewer lines that carry sewage and rainfall through the area. In dry weather, all flow is routed to the Wards Island Treatment Plant, but when it rains heavily the wet-weather flow overflows through the numerous individual outlets into the Harlem River.

Community Visioning Session Follow Up

Our February “Re-imagine the East Harlem Waterfront” session was a great success! Thanks to all Advisory Committee members who attended and helped spread the word of the event. Extra special thanks to Ethel Velez for arranging use of the Johnson Community Center and Rob Bennaton for his tireless outreach to area NYCHA residents.
Almost 100 participants circulated through our multiple stations, providing fantastic input and direction for our work. We’re busy analyzing all the information and combining it with our observational study and early survey results, but so far we know that:
1) Residents desire more greening of the East Harlem waterfront and neighborhood;
2) Safety concerns affect community members’ perceptions of the esplanade; and
3) There is a strong desire for increased waterfront programming and a physical connection to the water.
Our photo booth activity not only allowed us to capture a tally of desired waterfront activity, but was also a lot of fun. You can see the photos – and other shots from the event – at
Our largest engagement event may be behind us, but we’re not done with our outreach! Despite great success tabling in the community, we still need many, many more surveys completed – and need your help spreading the word about it! Please feel free to copy and paste the info below to send to your friends, colleagues and organizational contacts. Survey participants are still eligible for the $100 drawing for a few more weeks!

Harlem Creek: Past & Present

The Harlem Creek and the wetlands around it shaped Harlem’s historical development. This naturally fertile area influenced settlement, fueled rapid urbanization, and affected the landscape through infrastructure. While the present East Harlem landscape has changed from its historic origins, the historic characteristics of the Harlem Creek and the low wetland area reassert themselves even in today urbanized landscape.

The Harlem Creek and the wetlands around it shaped Harlem’s historical development. This naturally fertile area influenced settlement, fueled rapid urbanization, and affected the landscape through infrastructure. While the present East Harlem landscape has changed from its historic origins, the historic characteristics of the Harlem Creek and the low wetland area reassert themselves even in today urbanized landscape.

TM Catalog of Charecteristics


Two principal tributaries fed into the Harlem Creek. One originated just west of Central Park around 90th Street and flowed northeast, through McGown’s Pass [also spelled as McGowan’s]. McGown’s Pass was a gap in the steep slopes and rocks up into the higher lands south of 106th Street. This southern tributary also received the flow from a freshwater spring known as “Montanye’s Fonteyn” [also spelled as Montayne’s Fountain], that was also located within the bounds of today’s Central Park. This tributary of Harlem Creek is still visible today in Central Park, where the stream flows along “The Loch” on its way to the Harlem Meer lake.

The second tributary flowed from the north-west and was the principal waterflow that formed the Harlem Creek. The main route of this stream was from approximately the intersection of 121st Street and St Nicholas Ave (at 8th Avenue), then south-east to approximately 110th Street and 5th Ave (now the corner of Central Park and the Harlem Meer).

The combined streams then flowed eastward in a very wide channel toward the Harlem River. This wide channel between Fifth Avenue and the Harlem River was the largest portion of the Harlem Creek. The creek’s outlet into the Harlem River was at approximately 107th Street, and at high tide the saltwater from the Harlem River would also flow inland along the same route.

The former Harlem Creek and its watershed were covered and drained by combined sewers within the sewershed of the Ward’s Island Water Pollution Control Plant (WPCP) in the 19th and 20th centuries.With the shoreline extended through landfill, and the channel of the stream filled in, little visible evidence of the old Harlem Creek exists today. Its watershed, salt marshes, and meadows, which originally attracted settlers to the area, have been deeply altered by urbanization.


One way that the historic Harlem Creek and wetlands still affect the area today is the susceptibility to flooding. Despite the landfill in the 19th century, the area’s elevation is still very low, especially along the old wetlands areas. This occurred in 2012 during Hurricane Sandy, when flooding occurred along the FDR and the Esplanade and came inland several blocks along the former route of the Harlem Creek.

Overall, most of the land between the Harlem River and Park Avenue is less than 15 feet above Mean High Water (MHW), meaning that much of it is susceptible to flooding according to FEMA Flood-Risk maps for 100 and 500-year storms. This will only become more commonplace a risk as climate change causes a more rapid recurrence of strong storms, and so environmental resilience is a particularly important consideration for this low-elevation region.


New York City, like many older cities in the United States and Europe, has a combined sewer system in which sanitary sewage is mixed with rainwater runoff and groundwater flow. Originally, in the 19th century, these combined sewer lines were designed to outlet directly and without treatment into the Harlem River. Today, “interceptor” sewers divert the sewage to treatment plants before it can flow into the river. However, when it rains, the volume of the mixed sewage and rainwater runoff is too much for the treatment plants or interceptor sewers. This leads to “Combined Sewer Overflows” or CSO events. There are many CSO overflow points into the Harlem River, and these let untreated sewage out whenever there is significant rain. An important priority for New York is to reduce or eliminate these CSO events, which will improve water quality and environmental health. One way to do this is to create more permeable (un-paved) areas that can absorb rainwater that would otherwise run off the streets and into the combined sewers. Large treepits, for example, can absorb some of this water, as do other forms of green infrastructure.

The first major sewers in East Harlem were built in 1871, along the former above-ground route of the Harlem Creek. That year the city opened East 106th and 107th Streets from 5th Ave to the Harlem River, covering over most of the area that had formerly been the Harlem Creek and wetlands.Beneath the streets were the sewers, which carried both the water from the creek as well as the area’s sewage.

The largest of these sewers is underneath 110th Street, with a diameter equivalent to a circular cross-section of ten feet. It is one of the three largest sewers in Manhattan. Not only was the tunnel huge— carrying a large load of sewage from location populations into the Harlem River– but it was also draining an exceptionally large “sewersshed” area of 700 acres, making it by far the second largest drainage area of any Manhattan sewer at the time.

The sewers helped make it possible for the area to develop, but they also led to pollution of waterways like the Harlem River. In 1849, there had been only 69 miles of combined sewers in Manhattan; by 1908 there were 522 miles, all carrying untreated sewage into the water around the island. In 1910, an extensive examination of the city’s sewerage system concluded that: “The Harlem river, particularly at its southern end, is, at times, little else than an open sewer” due to the waste from the huge populations of Harlem, upper Manhattan, and the Bronx.

In the 20th century, the city began to construct sewage treatment plants. The treatment plant for East Harlem’s sewage is on Ward’s Island, which was the largest in the city when it was built in the 1930s. Near the outfall of the 110th Street sewer into the Harlem River, a new system of “interceptor” sewers was completed in 1937 to carry the combined sewage to the new treatment plant.

However, regardless of these interceptor sewers and treatment plant, there are still events when the untreated sewage is released into the Harlem River because rainfall has put more volume into the system than it can hold. Separating out these relatively “clean” waters– in the form of a re-created “daylit” streams, for example– has the potential have a profound impact on the quality not just of the estuary water but on urban environmental health as well.

Water Quality and the East River

The East River is a narrowly defined tidal strait about 25 km long, connecting the Harlem River, the Long Island Sound and the New York Harbor. The mean depth of the river is roughly 10 meters, with depths of more than 20 meters immediately north and south of Hell’s Gate. The Harlem River is also a narrow strait of roughly 12 km long, which connects directly to both the Hudson River and the East River at Hell’s Gate. The average depth of the Harlem River is 6.8 meters and the topography of the sea floor is relatively uniform. The tides of the East River are typically semidiurnal, or occur approximately every 12 hours. These tides create such water surface elevation that the strongest currents in the region occur in the river.Study Area

The history of water quality issues in the East and Harlem Rivers parallels the history of urbanization and wastewater.  When European settlers first colonized the land surrounding the New York Harbor, the population increased so much that the watershed, a convenient place for sewage and refuse disposal, soon became severely degraded. The abundant fishing and oyster harvesting that the Canarsie Indians and the Dutch had previously reveled in quickly dissipated, and by the early twentieth century typhoid outbreaks from bacteria contamination coupled with dredging and industrial pollution effectively shut down the entire oyster industry. Similarly, the waters were so polluted that very few fish could survive.

Watersheds all over the country were equally as degraded as the New York Harbor. To rectify this, congress passed an amendment to the Federal Water Pollution Control Act called the Clean Water Act (CWA).  The CWA established permitting requirements for discharging pollution into waterways.  The goal of the CWA is to make all waters in the US swimmable and fishable.  While waters in the US, including those of New York Harbor, have greatly improved from the 1970s, some have criticized the CWA for unsuccessfully dealing with the problem of urban stormwater runoff and other causes of water quality impairment such as combined sewer overflows (CSOs).Water Cycle

Water quality indicators that are often looked at by the Environmental Protection Agency (EPA) or other state environmental departments such as the NYS Department of Environmental Conservation (DEC) include fecal coliforms, which can indicate the presence of pathogens that can make people sick if ingested; dissolved oxygen, which is necessary for fish survival and is often impeded by nutrient loading; nutrients, such as nitrogen or phosphorus, which can cause algal blooms and low oxygen levels; and water clarity, which can be impeded by solids in the water such as sediment or algae and can also lower oxygen levels.

Water quality in the East and Harlem Rivers has improved dramatically since the 1970s.  Most importantly, dissolved oxygen levels have risen, which means aquatic life is in better shape than it used to be.  However, the East and Harlem Rivers still do not meet all of the water quality standards, mostly because of stormwater runoff and CSOs.

One of the most prolific pollutants in the East and Harlem Rivers is mercury, a heavy metal that is a serious human health risk, especially to pregnant women and young children.  Mercury is transferred to our waterways via stormwater runoff, CSOs, and can even be deposited from the atmosphere.  Fish ingest mercury and the metal becomes stored in the fatty tissue of the fish, thus creating a hazard for those who may fish in New York City waters.

To deal with the mercury issue, New York City, in collaboration with the EPA, developed what is known as a Total Maximum Daily Load (TMDL), which is essentially a pollution budget meant to lower loading levels of mercury in the water.  To date, mercury is still problematic in the East and Harlem Rivers, as well as all of New York Harbor.  Some have criticized the TMDL program for not being able to effectively deal with the issue of nonpoint source pollution.  Nonpoint source pollution is pollution that does not come from a fixed point, i.e. the end of a pipe, but rather it comes from water runoff during wet weather events that picks up pollutants from roadways and roofs and deposits them into the waterway.

Oyster BedMany organizations are deeply involved in resolving the water quality issue of the New York City Harbor. A few are as follows:

  • The DEP is investing in grey or engineered infrastructure to reduce nitrogen in the wastewater effluent, or the filtered water that is put back into the water cycle after passing through the water treatment facility.
  • The DEP is also investing in green infrastructure, such as enhanced tree pits and bioswales, and is working with many different organizations in New York to implement this technology which will assist in the capturing and filtration of stormwater.
  • Partnerships such as the Oyster Restoration Feasibility Study, are multi-organizational programs that are investing in education, outreach and technology concerning the future of the ecosystem in the New York Harbor.

Waterfront Design and the East River Esplanade

Foundational Concepts

As part of the greater Hunter East Harlem Studio, we are looking at what principles of waterfront design can address the long standing financial and ecological disinvestment along the Harlem River. Alongside ideas for updating a neglected riverfront, this project acknowledges that our changing climate and significant weather events require ever more vigilant recognition, and for waterfront cities this begins by taking a more holistic approach, by thinking of the water’s edge instead as something more graduated and alive.

There are three components that are important elements of a sensible redesign for the EH waterfront: The shoreline, the public pathway and the ability for the community and public at large to be able to access the space.

The Shoreline

One of the major challenges to the redevelopment of urban shorefronts is addressing vestiges of industrial city era design. Seawalls and bulkheads allowed for the ease of shipping and trade, but wreaked havoc on both the ecosystem and on the public’s ability to genuinely access the waterfront. Compounding the environmental loss caused by “hard” bulkhead edges, wear and tear on waterfront infrastructure requires frequent maintenance and replacement of bulkheads, seawalls, and stabilized shorelines.

A solution promoted today is to “soften” these hard industrial waterfront edges.   “Soft edges,” or graduated edges [created where possible], combined with staggered or curvilinear shorelines, reduce the speed and force of tidal action and waves, limiting erosion, damage and long-term maintenance costs. Replacing straight shorelines, particularly in places where inlets and coves can be reestablished, can create conditions more similar to natural shorelines and encourages bioremediation.  This is often accomplished with terraced shores, which can absorb wake energy and reduce scouring and erosion. Similarly, segments of unadorned shorelines, in the form of earthen banks, do not exacerbate wave action, and with their layers of plants, roots, soil and rock, can clean polluted runoff.

Varied surfaces encourage the return of strong and diverse habitats and encourage algae and filter feeders to attach. Additionally, living water filtration systems, which filter water pollutants and excess unwanted organisms, can either be grown naturally through the colonization of bivalves (oysters and mussels), or can be introduced as a more visible man-made design element, such as gabions – wire baskets filled with oyster shells and rocks that encourage filter feeding shellfish and grasses to attach.

The Public Pathway

An esplanade’s pathway is the critical bit of usable infrastructure for most visitors. Allowing for harmonious cooperative use of the passage by runners, walkers, bicyclists, and those passively enjoying the space requires design that acknowledges both the intended uses of the esplanade and the site’s space limitations. The pathway should promote safety, allow for mobility of all users, be contextual (a meeting of the neighborhood and the water), be visually coherent, reasonable in cost, and promote sustainability in materials and function.

The division of pathway space on the esplanade should accommodate amenities that promote both the passive and active uses in ways reflective of community needs and activity patterns. Pathway design and use of surface materials can help delineate spaces along the recreational thoroughfare where necessary (for safety) as well as integrating space into the broader landscape created for overall enjoyment. Where possible, the paths can bifurcate, typically keeping the bicycle path closer to the adjacent roadway, and allowing the separated pedestrian path to meander closer to the shore. In instances nearer to the water [non-seawall sections], the pedestrian path can be purposefully “broken,” so that it integrates with the shoreline more harmoniously and encourages interaction with the water.

Site Specific Practices

Fishing is a favorite pastime among many esplanade users, and should be supported by learning what sort of on-site amenities can be used by the fishermen – such as cleaning tables, rod holders, and even restrooms.

Many people choose to bicycle along the East River Esplanade, and while the majority pass through in transit, there are noted examples of bicyclists using lampposts or other available surfaces to lock their bikes while exercising nearby. Bicycle racks should be located near all entrances and places of interest along the esplanade [such as the pier] to encourage multi-modal enjoyment of the space and improve it as a destination for those beyond a short walk away.

A variety of seating should be staggered at regular intervals along the waterfront for both groups and individuals. Because the waterfront is inherently a destination, both in purpose and in practicality [particularly in the study area], these passive recreation spaces should be plentiful. Seating areas and types include chess tables and seats; benches along the waterfront; benches along the path [street-side]; picnic tables and other small seating areas that encourage interaction; stone and concrete ledges and blocks; stairs to nowhere [mini stadium areas]; and staggered getdowns at the water’s edge.

In the context of design, purposeful greening should complement these spaces for passive and active recreation. This can entail a variety of shrubs and groundcover for aesthetic, ecological, and functional benefit. Deliberate selections and placement of flora can give visual cues to trails, exits and entrances, act as a sound barrier against traffic, and imbue visitors with a sense of calm.

Community Access

Access refers to both the ways of approaching the site as well as the ability for all to enjoy opportunities to get to the water’s edge. This is enabled by obvious and usable upland connections and clearly illustrated open spaces and their entrances. One of the most efficient tools to promote wayfinding is through well oriented signage. Best practice calls for uniform design elements including matching fonts, size, coloring, and universal recreational symbols, all easily read and provided in multiple languages. Signage may also warn of safety hazards, identify plant species, or highlight the sponsorship or patronage of an individual, group, or agency to promote ownership of the space.


A discussion on safety along the esplanade must highlight the very real highway obstacle standing between the shore and the upland neighborhood. Clear, unobstructed, pedestrian-friendly connections to the waterfront through red light crossings along the FDR at several points would provide a common sense way of improving pedestrian safety and improving access – and getting people to the edges comfortably.

Public Art

Art installations can be used to promote both wayfinding and destination building. Public art can find unity at the meeting point of function and form, positively defining a site by improving association with an avenue of entry. Because the goal of revitalizing a waterfront is to encourage new and greater interaction with that space of interchange, art can be used to educate and direct the public through [for example] signage that is produced not only to help wayfinding but to reflect a sense of the community, or creative application of necessary markings [bicycle lane indications, wayfinding arrows] that enliven space while simultaneously informing and instructing.

Moving Forward 

The waterfront esplanade offers many opportunities for a dramatic makeover. Looking at the present openings, areas where the seawall and pilings are crumbling beneath the esplanade offer opportunity in that they require very immediate attention and physical work to be done. By undoing the seawall in these areas and beginning the inevitably piecemeal process of reconstructing the esplanade, one could learn from each step what can and should be done, one crumbling section at a time.

Practically, this studio should begin by identifying the ways that the Esplanade does not conform to proposed design guidelines and standards. A redevelopment of the Esplanade may not grossly change the totality of space from 103rd Street to 125th Street. However, it should, in every stretch, address the widths and surfaces of walkways, how remaining hard edges should look and feel, and how to smartly use the space’s finite width and deal with the noise and traffic directly to the west – how to insulate the area, where should planted areas be, and what sight lines to preserve or create.

Additionally, we can look at how TreesNY might temporarily or permanently fill these gaps, how to advocate for their resolution, and how to engage the community in the process. To gauge how realistic these efforts could be, we must identify where the jurisdictional overlaps are, what agency standards are chief, and how to fit the various requirements into our design plan.

A History of Physical Changes with Little Social Benefit

During the 19th century, Randall’s and Ward’s Island were used primarily as garbage dumps, cemeteries and poorhouses, as well as to process immigrants until the operation was transferred to Ellis Island at the end of the century. As the century wore on, the islands also became known for their hospitals. The earliest was built in 1843, followed by the Manhattan State Hospital in 1890, and by two ten-story military hospital buildings in 1918.

As Randall’s Island became dedicated to health facilities East Harlem was beginning a socioeconomic descent into a troubled area with a concentrated number of health issues. At this time, the idea to build a hospital on an island was regarded as a way to keep population out of diseases and infections. Yet, it served to build the gap (at least a functional gap) between the Island and East Harlem.

After the Great Depression, the proffered solutions to the health and social issues of neighborhoods such as East Harlem increasingly came to focus on slum clearance and the construction of modern housing. With the 1937 National Housing Act, cities were free to establish their own housing authorities to build public housing. In 1938, the New York City Housing Authority began clearing the neighborhood’s slums and in 1941, the East River Houses were built, the first modem high-rise housing projects in East Harlem.

At the same time, while erecting the Triborough Bridge, Parks Commissioner Robert Moses set about converting the surplus area on Ward’s and Randall’s Islands into parks. Joining with landfill and an additional 46 acres, the built out island would have see the introduction of 22,000 seat Downing Stadium, numerous athletic fields and a parking lot for 4,000 vehicles.

This intervention on the urban fabric intensified across the Harlem River with Title 1 of the U.S. Housing Act of 1949. Robert Moses, now chairman of the New York Committee on Slum Clearance, designated all of East Harlem for demolition. Though in the end one third only was destroyed the intent was clear: The physical order of East Harlem was deemed responsible for many of the issues that plagued it. The proponents of Urban Renewal had believed that clearing the slums and replacing defective housing by modern high rises would solve the health and social problems of East Harlem. However, the radical transformation of the neighborhood would instead negatively affect the social fabric of East Harlem as well as its economy. Low-rise buildings continued to be replaced by massive public housing developments, and by 1967 15,657 units had been built. The housing projects cut across old neighborhoods and communities and created physical barriers to travel even as they created unappealing or off-limits “green belts” of air, space and playgrounds within East Harlem.

Population Trends

After an all time population high of over 200,000 in 1950, numbers in East Harlem declined significantly through 1980 before finally slowing during that decade and ultimately picking up again in the last two decades to reach 120,511 in the 2010 Census. The last decade’s 2.4% population increase has been accompanied by a 9.3% increase in the total number of housing units.

Within East Harlem, the areas that saw the biggest increases between 2000 and 2010 are at the neighborhood’s edges. In particular, two census tracts in the southern part of the neighborhood, near Central Park and East 96th street, have seen their population increase by over 35%, while three other areas – all along Park Avenue – have increased by over 20%.