Nothing has had a more powerful impact upon the course of New York City’s history and prosperity than its natural position on the water at the confluence of the Hudson River and the Atlantic Ocean. Each borough has extensive stretches of shoreline. Except the Bronx, all are either islands (Manhattan and Staten Island) or part of a larger island (Brooklyn and Queens are part of Long Island).
New York City not only abuts the Hudson River and the Atlantic Ocean, it also borders numerous bays, rivers, and tidal straights including New York Harbor, Long Island Sound, the East River, Jamaica Bay, and the Harlem River.
Perhaps nothing has more powerfully shaped the city than the relationship between its land and water.
Over the centuries, New York City’s shoreline has been altered dramatically. Waterways have been dredged to accommodate increased shipping and larger ships, piers and bulkheads have been built, and landfills have been used for centuries to increase the acres of shoreline land that could be developed.
Throughout the city’s history, shoreline alterations helped New York City’s economy to flourish, but some natural features that keep marine ecosystems healthy and buffer shorelines were lost in the process of these alterations.
As a result, New York City’s people and assets are exposed to greater risk today than in the past.
New York City’s topography varies greatly across the five boroughs. The natural elevation, for example, ranges from less than 50 feet for most of Manhattan, Brooklyn, and Queens, to nearly 300 feet in northern Manhattan and the Bronx. This topographical map provides an overview of New York City’s topography and the highest point in each borough.
Staten Island’s Todt Hill is the highest point in New York City, rising 412 feet above New York Harbor.
Along New York City’s waterfront, human intervention and land reclamation have altered the city’s topographic landscape. The extent of reclamation is significant in Lower Manhattan, where landfill was used to provide the many acres needed to build Battery Park City and other large-scale developments.
Many areas that are built upon landfill are very low-lying — an important feature of New York City’s risk profile, which amplifies preexisting vulnerabilities in coastline neighborhoods, particularly during coastal storms and other severe weather events.
Geomorphology is the study of landforms and other geographic features and the processes that shaped them over time. Understanding New York City’s geomorphology — is critical to understanding why the city is vulnerable to coastal storms and earthquakes. New York City sits on land shaped thousands of years ago by a giant glacier known as the Wisconsin Ice Sheet. About 20,500 years ago, the glacier reached the area that would become New York City, grinding up rock as it traveled south and carrying chunks of gravel, pebbles, and sand with it.
About 18,000 years ago, the glacier began to melt, depositing rock debris at its southern edge and forming a terminal moraine as it retreated — the hilly area stretching through Staten Island and central Brooklyn and Queens.
Streams from the melting glacier carried deposits of sand, silt, and clay, forming outwash plains — today’s low-lying stretches along Staten Island’s East Shore and along areas in southern Brooklyn and Queens. These low-lying stretches have been vulnerable to storm surge during recent coastal storms. In the future, they will become even more vulnerable to rising sea levels, as detailed in this report’s Flooding and Coastal Storms hazard profiles.
The city’s unique geological characteristics also heighten the seismic effects of an earthquake. As shown on the map, geologic conditions range from solid bedrock at ground surface (green) to artificial fill (blue). Earthquake shaking is amplified by the sharp contrast between the soft soils of artificial fill and the extremely hard bedrock, increasing the risk of damage to the built environment. Large areas of the city have been filled to cover soft sediments and marshes to create new space for building development. For example, Manhattan’s present-day Chinatown is on land created by filling Collect pond. To learn more about earthquake risk, please refer to the Earthquakes hazard profile.
A barrier island is a long offshore sand deposit situated parallel to the coastline, often containing natural features such as beaches, dunes, barrier flats, and salt marshes that are separated from the mainland by a shallow sound, bay, or lagoon.
Barrier islands serve as a buffer against storms by absorbing the most severe impacts of pounding waves and storm surges. Tidal inlets often separate a series of barrier islands while also connecting bays with the ocean.
Long Island, stretching over 100 miles long with Brooklyn and Queens on its western shore, is home to multiple barrier islands and peninsulas, including Brooklyn’s Coney Island and the Rockaway Peninsula in Queens. Many inlets are artificially stabilized by an assortment of structures, and are dredged in order to allow commercial and recreational boats to navigate through the inlets.
Open Space, Natural Ecosystems, and Biodiversity
New York City’s open spaces vary widely, from natural to manicured, shoreline to inland, and large to very small. The parks and open spaces managed by the New York City Department of Parks and Recreation (NYC Parks) are vast, spanning over 30,300 acres, covering around 15 percent of the city, and encompassing approximately 4,200 sites.
They include many features and amenities, such as playgrounds, waterfront esplanades, wetlands, hiking trails, dog runs, boating and kayaking areas, athletic courts and fields, beaches, swimming pools, monuments and historic buildings.
About 40 percent of New York City’s open spaces are dedicated to beaches, boardwalks, and waterfront parks. These 12,000 acres of waterfront recreation property occupy approximately 160 linear miles – over 30 percent – of New York City’s coastline.
There are 26 distinct ecological habitats across New York City; about one-third of the area managed by NYC Parks preserves these habitats, including grasslands, wetlands, streams, among other natural areas – totaling approximately 10,000 acres. New York City’s natural ecosystems provide great benefit during extreme weather events, including by mitigating the urban heat island effect, absorbing stormwater runoff, and buffering inland areas from the impact of floods, high winds, and other extreme weather events.
In 2016, New York City planted its one millionth tree as part of its MillionTreesNYC initiative, which began in 2007 as part of PlaNYC. The City continues its efforts to expand and strengthen our urban forestry.(Source: NYC LiDAR Capture 2010 & 2017).
New York City is home to urban biodiversity that makes our ecosystems resilient to the impacts of natural hazards. Across the range of diverse habitats, the city is currently home to over 2000 plant species, 200 species of trees, 200 species of bees, and 400 species of birds. Many of the species living in New York City are native, meaning that over thousands of years they have adapted to our particular climate, soils, and environment conditions. With an increase of urbanization, many of these species have continued to adapt to the new conditions of cities. Unfortunately, however, many of these species are in decline and a large proportion of them are nonnative and invasive. Threats of urbanization, climate change, and environmental degradation introduce and allow new species to thrive while threatening native ones. There are at least 140 formally designated rare species living in the New York City. Increasing invasive species, given degrading habitat quality and busy international ports in the city, further threaten urban biodiversity.