The City of Winnipeg apparently has to pay for sandbagging of properties along the Red River every year. So, they have offered to build dikes on these properties to save money. If the property owner refuses, the city still has to supply sandbags.
http://www.cbc.ca/canada/manitoba/story/2007/04/11/dike-proposal.html
Sounds to me if you build in an area that is prone to flooding, you should be prepared to pay for protecting it yourself.