New Insights Into US Flood Vulnerability Revealed From Insurance Big Data

An international team of scientists, led by the University of Bristol, has found that current estimates of flood risk rely upon methods for calculating flood damage which are inadequately verified and match poorly with observations.

Instead, building damage at a given flood depth is highly variable and can be characterized by a beta distribution.

When calculating flood risk—that is, translating modelled representations of the physical of phenomenon of flooding to its impacts—it is common to apply a ’depth-damage function’ or curve, which relates a given water depth to a proportional building loss (for example one metre of water equals 50 per cent loss of building value).

Academics have understood that this depth-damage relationship is variable and that there is no perfect fit, but it is still common to apply such curves which are inadequately verified.

The new study, published today in the journal Nature Communications, used commonly applied curves, developed by various US government agencies, and examined how they compare to millions of actual flood insurance claims made in the US.