We always think of flood events on a macro level -- but effective mitigation can start AT HOME!
In the 1990s, just 2-3 years after moving into our Illinois residence, came the historic rains and floods which made for the highest levels of water on the Mississippi in modern history. What it ALSO did was flood our basement -- complete with boxes we hadn't yet unpacked from our move!
We discovered only AFTER this occurred -- a factor which is present in many many modern built homes. The homes in our development were built so fast, and never followed up on, that the soil had settled around the house and its foundation -- and made for water moving TOWARD the foundation instead of away from it! In this historic rain, we found water was filling the lightwells of our basement and then pouring in from there! It ruined much - and had us work long hours at restoring the partially finished basement ourselves.
What we didn't realize then, but do now (and recommend to all) is CHECK AROUND YOUR OWN HOME for such a condition! Should you have soil pitched toward your foundation, and maybe even have a trough or depression around the immediate area next to the foundation - FIX IT!
The fix can be by several means. One we used was to take clay soil (even taking out some regular soil) and placing it around the home while ALSO using it to fill the "depression trench" around the home caused by the settling. This soil was built up enough (and pitched outward), that between that layer and the layer of top soil we put over it (for plants and shrubs), the water would thereafter be going AWAY from the home and not TOWARD the home.
It really didn't take that much labor or time to do this (less than restoring our basement). But it has CONSISTENTLY prevented the same problem from every happening again!
So - ahead of any area flooding and rain caused damages to your community - HARDEN YOUR OWN HOME in this manner. You'll be very glad you did!