You're simply demanding even more government regulations. That's above those government regulations that already don't work. Why is it for you to decide what is a "know inevitable impact", and what is not known.
The best approach, in my opinion, is to let anyone build where ever they want. Just don't make government regulations to force me or anyone else to pay for it.
For over a millennium the Dutch have been building increased farmland below sea level by building dikes, almost all with out government regulations. After a dike is built, it takes over a century before the land becomes productive due to the salt in the soil. They did this, not for themselves, or even their children or grandchildren, but maybe for their great grandchildren. With government regulations, nothing, at all, could have been done. Arm chair regulations by over paid bureaucrats is never an optimum solution for any problem.
I’m okay with what you suggest. It’s just that when there’s flooding, everyone pays to replace the infrastructure...roads, utility bills and insurance, needs of displaced people etc. As it is now, we all pay in so many ways.