When I saw the dynamic water simulation I though the idea of a flood disaster was a perfect complement but this brought up the question that if a large part of my city was flooded at abandon buildings everywhere, when the flood waters subside, the rebuilding of houses should be a factor of how bad the flood was as this will have an econimc impact on the city and you could have a policy called "flood levy" which increases the rate of rebuilding after a flood through added tax