New York City is sinking. These spots are sinking fastest.

Start writing...According to a recent study, it has been observed that not all land within the greater New York City area possesses a uniform level. Certain areas, including prominent roadways and the venue for the esteemed U.S. Open tennis championships, are experiencing a significantly accelerated sinking rate compared to others. This phenomenon has consequential implications for the increased risks of flooding as sea levels continue to rise.

Researchers have discovered that several significant structures in New York City, namely a runway at LaGuardia Airport, Arthur Ashe Stadium, Interstate 78 (which includes the Holland Tunnel), and Highway 440 (connecting New Jersey and Staten Island), are experiencing a sinking phenomenon at a rate exceeding 2 millimeters per year. This rate surpasses the average subsidence of 1.6 millimeters per year observed in New York City. The findings were published in the journal Science Advances on Wednesday.

Brett Buzzanga, the lead author of the study and a coastal scientist at NASA's Jet Propulsion Laboratory, emphasized the importance of comprehending the impact of vertical land motion on coastal cities, particularly for the average citizen. Understanding this component is crucial in assessing the vulnerability to flooding, even within different neighborhoods.

In comparison, the minimal magnitude of subsidence in New York City, measured in millimeters, may appear insignificant. However, it has the potential to significantly worsen the issue of flooding in conjunction with the rising sea levels. According to a recent study, over the course of the past two decades, sea levels in Manhattan have risen at a rate of 4.4 millimeters per year, partly attributed to the sinking of the land. This phenomenon can have dire consequences during periods of extreme weather events. In fact, one study estimated that approximately $8 billion worth of damages caused by Superstorm Sandy in 2012 could be attributed to the rise in sea levels.

Buzzanga stated that there is a greater potential for damage when higher sea levels and lower land are combined. He explained that this combination increases the background state on which storms act, resulting in a larger volume of water being present.

Buzzanga and his colleagues utilized satellite data to develop a new technique for obtaining high-resolution measurements and comparing different neighborhoods. This study represents an improvement over ground instruments or airplanes equipped with GPS, as it allows for point-by-point collection of high-resolution data.

Buzzanga emphasized that their research provides unprecedented detail regarding the variations throughout the region. They discovered that certain areas are sinking at a faster rate than others, which can lead to increased flooding in those specific locations. He noted that this phenomenon is applicable to any city.

New York is among a number of coastal cities that are observing significant land subsidence. Additional studies have indicated that Norfolk and Virginia Beach, for instance, are experiencing an average sinking rate of over 3.5 millimeters annually. Certain regions surrounding New Orleans have encountered a sinking rate of 40 millimeters per year.

Land can subside due to various factors. In the case of New York City, a significant portion of its subsidence can be attributed to the retreat of glaciers during the last Ice Age. These massive ice sheets exerted immense pressure on the land, causing the crust to stretch and sag in regions like the northeastern United States. Nevertheless, New York City was situated on the periphery of this sagging zone and experienced an upward bulge instead. As the ice sheets gradually receded, the land started to even out, resulting in the rising of previously drooping areas and the sinking of formerly bulging regions.

The Arthur Ashe stadium underwent a renovation process that included the installation of a specialized lightweight roof aimed at reducing subsidence.

Furthermore, the study revealed unexpected areas where land was experiencing uplift. For instance, in East Williamsburg's Newton Creek in Brooklyn, there was an observed uplift of approximately 2 millimeters per year. The study highlights that the area is undergoing a significant engineering project aimed at recovering and treating polluted groundwater from the creek's aquifer, which could be the cause of the land's uplift. However, it is important to note that rising land can also pose a threat to infrastructure stability.

Tom Parsons, a geophysicist at the U.S. Geological Survey who was not involved in the study, expressed his admiration for the authors' ability to produce subsidence and uplift data with such high resolution.

The conclusions drawn by the researchers are consistent with the findings of Parsons and his associates, indicating that infrastructure constructed on or near the coast on top of artificial fills tends to sink at a higher rate. Parsons has stated that this study validates the usefulness of satellite data in assisting major cities in managing various issues, such as the location of large buildings, the use of artificial fill, and the identification of areas requiring protective measures against future inundation.

Steven D'Hondt, an oceanography professor at the University of Rhode Island who was not involved in the research, has suggested that the settling of areas built on landfill may be exacerbated by the weight of buildings and runways. However, the sinking caused by the additional weight of infrastructure typically ceases within a few years of construction and is not a primary cause of land sinking.

Buzzanga and his colleagues intend to employ their newly developed algorithm to provide vertical displacement data throughout North America, which could aid in assessing a community's flooding risk and city planning. D'Hondt has stated that every city in the world would benefit from such a refined analysis of vertical land motion throughout the city.