"D" == Doug writes:

D Not as crazy as it sounds. Dig a big lake, convey the dirt
D over. All the houses worth saving, raise them up on a new
D foundation. The skycrapers, just make the bottom floor a
D basement. Expensive? Yes, but a permanent solution. Better than
D it happening again.

It's been done befo

"After yet another massive flood in 1862, an ambitious project to
actually raise [Sacramento] above flood level was undertaken. Evidence
of the tens of thousands of cubic yards of earth and miles of masonry
work used to raise the streets can still be seen today in Old
Sacramento." And the downtown if you know where to look.