A major reason is too much groundwater is being pumped out, new research shows, threatening buildings and infrastructure nationwide.
Excerpt from this New York Times story:
A new analysis of America’s 28 largest population centers found that all but three are sinking overall, and in many cases significantly.
Several of the most affected areas are in Texas, particularly around Fort Worth and Houston. But the problem is nationwide, affecting cities as scattered as Seattle, Detroit and Charlotte, N.C.
The sinking of land, also called subsidence, can worsen the effects of sea-level rise, intensify flooding and strain the very foundations of urban infrastructure.
The new research, published in the scientific journal Nature Cities, built on previous work using satellite measurements to paint a detailed picture of rising and falling land. It also closely examined the connection between changes in land elevation and changes in groundwater, using data from individual monitoring wells.
Water pumped from wells isn’t something that people think about often. “You just turn on your tap, do what you need to do, and you go on your way,” said Leonard Ohenhen, a researcher at Columbia University’s Lamont-Doherty Earth Observatory and lead author of the study.
But extracting more water than can be replenished “can have a direct relationship with what happens on the surface,” he said. “You can cause the ground to sink significantly."
A 2023 New York Times investigation found that unsustainable pumping of water from underground aquifers can be a major cause of sinking land.
Other factors also influence land elevation. For example, a vast expanse of bedrock beneath parts of the country, pressed downward by enormous glaciers during the last ice age, is slowly rebounding back into place. But over time it creates a sort of see-saw effect that today is adding 1 to 2 millimeters per year to subsidence rates in much of the northern United States.
Texas draws immense amounts of groundwater for agriculture, industry and the public water supply. The extraction of oil and gas, including the growing use of “monster fracks,” can also cause the land surface to slump.
Climate change can worsen the issue. Hotter temperatures and more extreme droughts, particularly in the West, dry out soil, streams and reservoirs, leading people to pump larger quantities of freshwater from underground.
Americans have also been moving in droves to some of the hottest and driest parts of the country. In the past few decades, metro areas in Texas have ballooned in population and sprawl.
