Good post / info. Although I must say, in most of my area (parts of which flood fairly often), new development in areas subject to flooding is severely curtailed, with no new residential development there at all. More or less “grandfathered” farming, yes, older homes & a few (might not even be very old) businesses, yes, maybe a marina or 2... but entire nice new neighborhoods going into a floodway or detention area would be unthinkable.
Granted, we do not have the population growth of Houston.
New Voluntary Evac, south of Addicks, east of Barker. Mayor “strongly urges” people to leave, additional releases and tough conditions “for 10 to 15 days”: