As if maintenance and engineering managers didn’t have enough issues to deal with in the life of facilities. They need to protect facilities from wear and tear from traditional weather, as well as from catastrophic storms and other natural disasters. They regularly have to repair facilities from everyday wear and tear. Now, many are having to contend with the ground that is shifting underneath them and their facilities — literally.
The nation’s biggest cities are sinking based on data from a new study, according to USA Today. Known scientifically as land subsidence, the most common cause of the sinking is massive ongoing groundwater extraction, say the study’s authors, though other forces are at work in some places. The cities include those on the coasts, where sea level rise is a concern, and many in the interior.
In every city studied, at least 20 percent of the urban area is sinking, and in 25 of 28 cities, at least 65 percent is sinking. The study “offers critical information for urban planning, infrastructure adaptation, and hazard preparedness,” he added.
The nation's fastest-sinking city is Houston, with more than 40 percent of its area dropping more than 5 millimeters per year, with 12 percent sinking at twice that rate.
When land shifts downward even a small amount, the structural integrity of buildings, roads, bridges, and dams can be profoundly impacted, says Leonard Ohenhen of the Lamont-Doherty Earth Observatory and the study’s lead author.
Ohenhen says some early warning signs of subsidence that are often overlooked include: cracks in walls or foundations or around windows and doors; uneven or sloping floors; doors and windows that no longer close properly; warped roads or buckling pavement; tilting fences or utility poles; and fire hydrants sticking above ground more than they used to.
Dan Hounsell is senior editor for the facilities market. He has more than 30 years of experience writing about facilities maintenance, engineering and management.?
