Study finds Detroit is sinking this much each year
Detroit, along with 27 other major U.S. cities, is sinking, a recent study finds.
The Motor City, the Big Apple, D-Town and the Emerald City are sinking 2 to 10 millimeters per year, according to a study of the 28 most populous U.S. cities.
The study was conducted by researchers from Virginia Tech, the Netherlands Organisation for Applied Scientific Research, the University of California Berkeley, Texas A&M University, the University of Colorado Boulder, Brown University and United Nations University. It was published May 8 in Nature Cities, a monthly, online journal that features research and opinion about cities and urban issues.
Leonard Ohenhen, the study's lead author, said the study found Detroit has sunk by approximately 10.2 millimeters, or about 0.4 inches, from 2015 to 2021, based on an average land subsidence rate of 1.7 millimeters per year.
The study said the main reason for most cities sinking is groundwater extraction.
But in Detroit, glacial isostatic adjustment is to blame, according to Ohenhen, who is a postdoctoral researcher at Lamont-Doherty Earth Observatory in Columbia University's Climate School in New York.
The phenomenon is a slow, natural process resulting from the planet's response to the retreat of ice sheets following the last glacial period, he explained. "In addition, some localized settling may occur in areas built on reclaimed lands, though such cases are limited in spatial extent," the researcher said.
But there's no cause for widespread panic in Detroit, Ohenhen said.
"The observed subsidence in Detroit is relatively uniform, posing little to no immediate risk to infrastructure," he said. "However, even gradual sinking can exacerbate the risk of flooding in the city, particularly in areas with poor drainage or during extreme precipitation events."
Not much can be done to stop it, either, according to the Ohenhen.
"Because the main driver is a natural geophysical process, subsidence in Detroit cannot be mitigated in the conventional sense," he said. "Instead, adaptation is key. This includes integrating land elevation change into stormwater management, urban planning, and resilient infrastructure design, ensuring the city remains equipped to handle incremental changes over time."
Ohenhen and his team of researchers used satellite data to measure the amount land sank, or what's called subsidence, for the U.S.'s 28 most populous cities. Combined, the cities are home to about 34 million people — about 12 percent of the country's total population.
The study found that in every city, at least 20 percent of the urban area is sinking. Furthermore, in 25 of 28 cities, at least 65 percent is sinking.
It said Houston is the fastest-sinking city, with more than 40% of its area subsiding more than 5 millimeters, or about 1/5 inch, per year, and 12% sinking at twice that rate. Some spots are falling as much as 5 centimeters, or 2 inches, per year, according to the study.
The study also said two other Texas cities, Fort Worth and Dallas, are not far behind Houston when it comes to subsidence.
Other fast-sinking zones were discovered in areas around New York’s LaGuardia Airport, parts of Las Vegas, Washington, D.C., and San Francisco, the study found.
This article originally appeared on The Detroit News: Study finds Detroit is sinking this much each year