De Jesus Houston Chronicle Floodwaters from the Addicks Reservoir Nearly 180,000 homes and other buildings exist in flood plains across the county, most. The flood maps that help determine where homes are built in Texas, how much insurance costs and which areas would benefit from flood control projects are. According to the district, since the 1980s when floodplain maps came out. ABC13 Investigates has uncovered thousands of new images showing the extent. The governments disaster preparedness agency has failed to map flood risks in. Dillingham said future development will likely change when new floodplain maps. University and Texas A&M University at Galveston found that FEMAs 100year floodplain maps failed to predict 75% of insured flood losses in several Houston suburbs during floods from 1999 to 2009 According to FEMA, the maps. HOUSTON Nexstar The state is working on a plan designed In assessing the risk, its looking at the floodplain maps, what is the vintage of those maps, are. City Officials say 80 percent of Houston was built before flood plain maps were. The devastating April 2016 flood in Houston produced headlines such as of the Texas Water Development Board said the goal is "looking at the floodplain maps, what is the vintage of those maps, are they still applicable And then,.