As this earlier post noted, the Harris County Flood Control District released its preliminary new flood plain maps for five Houston watersheds today. Here is the site at which you can check an address against this latest flood plain information. The new flood plain maps will have a major impact on real estate development decisions and on plotting better ways to protect Houston from catastrophic flooding similar to what occurred in 2001 during Tropical Storm Allison. Within the so-called 100-year flood plain — the area with a theoretical risk of flooding once every 100 years — flood insurance is mandatory and the City of Houston imposes development requirements such as elevating buildings or digging detention ponds. These measures can substantially increase the cost of development. The information released today is a draft version of the Federal Emergency Management Agency‘s Digital Flood Insurance Rate Maps, which are expected to be released in late spring. An appeals process will follow over the next several months before those maps become final.