A Looming Crisis as Cities Sink and Seas Rise

Engineering Influence from ACEC

In a concerning discovery, cities across the US are steadily sinking due to practices such as groundwater extraction, oil extraction, and fracking, exacerbating the impacts of sea-level rise. This article, which originally ran in Engineering, Inc., delves into the severity of the situation, highlighting how a considerable number of American and global cities, housing 10s of millions of people, are dropping at an alarming rate every year. Land subsidence – the sinking of ground level – is largely irreversible and carries serious repercussions, including increased flood risk and potential relocation of affected communities.

As experts emphasize, the primary culprit is the over-extraction of groundwater, which is responsible for more than 80% of U.S. land subsidence occurrences. Despite elemental damages like floods, earthquakes, or landslides being resolvable over time, loss of elevation due to land subsidence is permanent and difficult to notice until it's too late. Therefore, it's vital to comprehend that land subsidence amplifies all other environmental impacts, including relative sea level rise, essentially characterizing the intersections of sinking land and rising seas.

Though land subsidence can't be reversed, stabilization is possible through processes like managed aquifer recharge. Some cities are already testing such solutions with the hope to slow down and stabilize ground subsidence. Nonetheless, considering the increased storm surges and rainfall, the real challenge is to rethink how cities use stormwater to naturally replenish groundwater resources, which currently is not the case in most urban areas. Plans to effectively manage stormwater and allow it to seep back into the ground to recharge groundwater reserves are discussed.

However, the graveness of the issue also extends to climate gentrification. With the rising sea levels and decreasing land, neighborhoods sitting above sea levels are becoming prime real estate, forcing locals out. Experts advocate for infrastructure with multiple functional benefits and a balanced approach that takes into account all members of the community. As cities sink and sea levels rise, engineers are called to action to ensure sustainable futures and reevaluate the relationship between the built environment and nature.