Adaptation expert Paul Kirshen proposes a new paradigm for civil engineers: 'safe to fail,' not 'fail safe'

Jennifer Weeks in the Daily Climate: Civil engineers build rugged things designed to last for decades, like roads, bridges, culverts and water treatment plants. But a University of New Hampshire professor wants his profession to become much more flexible.  In a changing climate, facilities will have to adapt to changing conditions over their useful lives – and, in some instances, be allowed to fail.

In a changing climate, civil engineer Paul Kirshen argues, facilities will have to adapt to changing conditions over their useful lives – and, in some instances, be allowed to fail. A leading example of this approach: The Netherlands' Room for the River project: Decades of thinking that floods must be held back are being tossed aside as workers move dikes to give the Rhine River room to spill.

The approach recognizes that the country's famed network of dikes and dams will come under increasing stress as sea levels rise. Rather than building protective walls ever higher, the Dutch believe they can keep safer by accepting a certain amount of controlled flooding. Kirshen, an expert on climate change adaptation and water resources, thinks the United States should take a similar approach.

"Historically we've built infrastructure to provide a certain level of safety," he said. A dam may be designed today to withstand a 100-year or 500-year flood, for example. But that approach assumes that engineers know how stresses – such as floods and storm surges – will vary over the dam's lifetime. As climate change alters natural cycles, Kirshen argues, those assumptions may prove false.

In some cases engineers will have little choice but to armor structures against rare extreme events – say, the 9.4-foot storm surge that Hurricane Sandy pushed into lower Manhattan last fall. But using such a rare flood or storm as a design standard is expensive, Kirshen said, since it means building new structures or retrofitting existing ones with enough protective features to withstand stresses that may occur only once in those buildings' lifetimes, if at all….

From 1990, Oosterscheldekering during a storm, shot by Rens Jacobs / Beeldbank V&W., Wikimedia Commons. The copyright holder of this file allows anyone to use it for any purpose, provided that the copyright holder is properly attributed. Redistribution, derivative work, commercial use, and all other use is permitted.