You say this, but in the Netherlands, they reclaim land lost to the sea by some funky pumping and crops planting, and then populate the land, much of which is below sea level. It's going to take a lot more than a boy with his finger in the Dyke to save that lot if the crap strikes. Here in the UK, the recent floods were often as a result of poor land drainage management and property developers buying up cheap flood plain land and building large housing projects.
If you are tight for space and restricted by Statute, I do not see a clever and cost effective way of meeting housing targets WITHOUT building in a potentially marginal location. In the Unites States, whilst there are favourable locations aplenty in marginal situations, I would have thought that there is a whole lot more choice of where to build, so if people become bloody minded and build anyway, then they must shoulder a lot of the responsibility if the sh1t hits the fan.