The big dig was not nearly as poorly executed as you might assume, digging in the middle of a major city is simply rediculusly expencive.
IMO, the best option is to simply raise buildings following the Chicago model. http://en.m.wikipedia.org/wiki/Raising_of_Chicago. A major advantage being you don't need to worry about flood control measures failing. It's not like the buildings are actually worth all that much it's 90% pure land value with a token for the structure. (Aka move the same building to the middle of an Iowa cornfield and suddenly there not so valuable.)
IMO, the best option is to simply raise buildings following the Chicago model. http://en.m.wikipedia.org/wiki/Raising_of_Chicago. A major advantage being you don't need to worry about flood control measures failing. It's not like the buildings are actually worth all that much it's 90% pure land value with a token for the structure. (Aka move the same building to the middle of an Iowa cornfield and suddenly there not so valuable.)