There is no 100 year rule. To the extent that "N-year floods" exist, or their hypothetical water levels, that is all more of an arbitrary label than a scientif

There is no 100 year rule. To the extent that "N-year floods" exist, or their hypothetical water levels, that is all more of an arbitrary label than a scientifically-valid designation. realistically they're measuring "big floods" and "bigger floods" in a way that is consistent, however the stated time frequency with which they supposedly occur is so extremely inaccurate that it does not rise to the level of 'science.'