Somewhat off topic but just some trivia from a geology weather class I took
100 year flood does not mean it happens every 100 years but there’s a 1/100 chance for it to happen annually
Putting climate change aside for a second for consistency sake, you could go for 150 or 200 years without a 100 year flood or on the other side only a 5 year gap for that 100 year flood if you’re unlucky