If they have not been hit for a century, it remains to be seen how well the existing kinds of flood defence will work out. Have they done anything to strengthen or at least maintain them since then?
That said, The Weather Channel is claiming that if it hits at high tide, the storm surge could be up to 15 feet, which is 5 feet higher than the average tsunami. I don't think any city is prepared for that eventuality.
It's probably because of the last sentence. Which technically is a fact (because they obviously think that), but 5m is something at least cities in northern Germany are usually prepared for.
I'm not sure how exactly the tides are measured and if it differs internationally, but we have floods at around 5m every few years without any significant damage (German source). Hamburg had a flood with 6.45m in 1976 without damage to the city (only the port and other parts outside the levees were obviously damaged; German source).
It's almost definitely worse, more development means more covered land which means more water flowing faster to holding areas, that likely aren't sized for the amount of developed land.
Why spend their own money, when they could just wait for that sweet federal money after a disaster? (While blaming the federal gov and being completely insufferable, ungrateful cunts.)