Then again if we go to global cooling the sea level might be a couple of thousand feet lower; there would be no beach at O.C; the Susquehanna River (Chesapeake Bay) would be flowing water to some some 60 miles east of Ocean City and drop off the continental shelf in a couple thousand foot waterfall.

Of course by then we would not need a dike but ice removal equipment to keep OP from a glacier cover.

Back to today, flooding is inevitable in a record or near record rainfall. However, the flooding can be mitigated by keeping ditches and pipes clean, and other appropriate maintenance.