Some U.S. Utilities are Operating in Sinking Cities
Image courtesy of Dale Cruse under Attribution 2.0 Generic Deed, resized to 700 x 391 pixels.
A new research study concludes that there are dozens of sinking cities across the U.S. 28 of the nation’s most populated metropolitan areas are rapidly losing elevation, and not just in coastal areas. This begs the question – what is the impact on utility companies?
Cause and Effect of the Sinking Cities
The study, published in the May 2025 issue of Nature Cities, attempts to map the scale of this sinking phenomenon across the U.S. It utilized satellite imagery to measure the shifting elevation in 28 large U.S. cities. The sobering results indicate that at least 20% of every one of these 28 cities is sinking, and 25 of them have at least 65% of their square mileage sinking. In total, we’re talking about 7,000 square miles of land that houses 34 million people.
The process that causes land beneath a city to sink is called subsidence. There are several reasons this occurs, including the collapse of aquifers from consuming too much groundwater (accounts for 80% of the cause), as well as long-term soil compaction from the sheer weight of the cities. Unfortunately, climate extremes will increase the demand for water which will likely accelerate the sinking in the future.
Currently, Houston is experiencing the most dramatic result, with 40% of it’s area sinking by more than 0.2 inches every year. Some areas of the city have lost several feet of elevation. Other problem cities include Las Vegas, Washington, D.C., Los Angeles, and San Francisco. In fact, some areas in California have lost an eye-watering 30 feet of elevation over time!
The main problem for utilities is “differential subsidence,” which is when different areas sink at different rates. If an entire area sinks at the same rate, it’s not much of a problem, but if part of the land sinks faster than other parts, it could destabilize infrastructure and cause road damage. Any utilities operating in an area like this should prepare accordingly.
The solution to this problem is injecting water back into the ground, a process called managed aquifer recharge. However, this is anything but a cheap and easy solution. Thus, if you are operating in one of the many sinking cities across the U.S., the time to prepare for subsidence – especially differential subsidence – is now.
