Could elevate about sf and nyc to start

Where water is expected to intrude due to expanse of coast (south), deep channels may be dug to assimilate water, with sub-channels to divert water into main channels. Dirt may be moved to elevate land at strategic locations

[removed without permission]

 Major farms located in Midwest

Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.

 

*note the elevation legend on the left of the first image. 

Water levels are not expected to be that far above sea level.

Canadian Oxford World Atlas 6th Edition, Quentin H. Stanford General Editor P70-71

 terraform