Flooding Disasters: The New Normal
Flooding seems to be getting worse, rendering data unreliable. What used to be 100-year floods may have to be redefined as 10-year floods
As a megaproject expert, I get to work on some of the largest infrastructure investments in the world. Repeatedly, I find flood risks have been underestimated because so-called “tail risk” — the risk of extreme outcomes — was ignored or underrated. This exposes infrastructures and cities to flooding disasters.
Climate change has exacerbated the problem by making historic flood data obsolete. But many engineers and policymakers keep using the old data — or make insufficient updates and adjustments — and seem surprised when extreme flooding happens.
As a case in point, consider the heavy rainfalls that broke the Edenville Dam in Michigan on 19 May 2020 and caused flooding that resulted in the evacuation of 10,000 people. Michigan’s Governor, Gretchen Whitmer, called it a “500-year event” and officials warned that with global warming such events would become more common.
A 500-year event that is becoming more common is an oxymoron.
But a 500-year event that is becoming more common is not only an oxymoron. It is no longer…
