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

HISTORY OF THE HARLEM CREEK

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.

FLOOD VULNERABILITY

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.

SEWAGE AND DRAINAGE

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.

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