Easier said than done. They basically need infrastructure to handle months (average month before 2000) of rain falling in a few days over several countries. Huge storm canals, dams and water basins that can divert and hold up to half a year of rain and that’s assuming climate change doesn’t make it even much worse in a decade.
Another 1-in-a-100 year weather event hits. They’re getting quite common for once per century disasters.