“As floodwaters from Hurricane Harvey recede in Houston, one thing that’s been revealed is that some of the damage — financial, physical, emotional — could have been avoided.
Flood hazard maps by the Federal Emergency Management Agency, showing the 100-year floodplain, an area with a 1 percent risk for flooding in any given year, mark where homeowners are required to have federally sponsored flood insurance. This is one of the few early warning signals the United States has for flooding. For Houston, those maps were thoroughly inadequate. Early assessments show many homes were flooded even though they were located far from the designated floodplains. Many homes in what’s known as the 500-year floodplain — with a 0.2 percent chance of flooding in a year — are also flooded.Areas surrounding the Katy Prairies, sprawling grasslands in western Harris County, provide one such example. The region has been heavily developed over the past 30 years, sometimes overlapping or abutting floodplains. Local officials did not do enough to preserve native grasses, set aside open spaces or improve drainage.”