At the same time, more advanced tools for control and safety have been introduced, such as radar and satellite monitoring, making it possible to detect millimetre-scale movements in numerous US dams.
A study presented at the annual meeting of the American Geophysical Union and reported on 2 January by the Washington Post showed how technologies such as InSAR (Interferometric Synthetic Aperture Radar) can detect subtle but persistent deformations, providing a valuable early-warning system.
The research, which analyses 41 large hydroelectric dams in 13 states, cites, among others, the Livingston Dam in Texas, a structure more than four kilometres long classified as high-hazard, where satellite data indicate vertical movements of a few millimetres per year. Added to this is the Roanoke Rapids Dam in North Carolina, where differential settlement phenomena have been observed.
The researchers stress that such measurements do not imply an imminent danger, but represent useful signals to guide in-depth inspections and targeted interventions.
This is also because new standards are now emerging worldwide. The focus is no longer solely, or primarily, on the design and construction of a dam and, once built, its maintenance. Attention has shifted to the overall and long-term reliability of the infrastructure, starting with the individual materials used, monitoring technologies, the protection of the public interest, the anticipation and management of emergencies, and extending to the enhancement of benefits for the communities concerned.