It's not 'adjusting how you call the storm'. It's the engineer defining his design criteria (the 'design-storm'), based-on and benchmarked-to local historical

It's not 'adjusting how you call the storm'. It's the engineer defining his design criteria (the 'design-storm'), based-on and benchmarked-to local historical data, including recurrent intervals. The wall doesn't need to be bigger if next years data changes. It was designed for a (this year) 100yr- or 500yr-storm, not a guess of hypothetical future one.