COMPILED FROM STAFF AND MEDIA REPORTS
Newly redrawn floodplain maps for the Blanco River basin in Hays County substantially expand the number of properties on which federal and state agencies say it is unwise to rebuild homes and businesses before weighing the probability of future natural disasters.
The Federal Emergency Management Agency began releasing revised floodplain maps on Friday, nearly three months to the day after unprecedented flooding wrought unprecedented devastation in parts of four counties. The first installment covers Wimberley and western Hays County, and the agency will soon publish modified maps for northern San Marcos and Martindale, according to the Austin American-Statesman, which first reported on the dramatic scope of the floodplain overhaul in a story published this morning.
Hays County staff “is actively reviewing the changes and comparing them to previous maps, historic flood data and existing development. … At this time, Hays County has not made a decision as to whether to use the advisory floodplain maps as regulatory maps, but would do so only after a full, public process,” according to a statement released late this afternoon by the county’s spokesperson.
Officials have scheduled an open house next week in Wimberley to “help leaders and residents identify where flood risk has expanded and use that information to rebuild less vulnerable to future flood events.” The meeting will be held 2 p.m. to 8 p.m. Wednesday, Aug. 26 at the Wimberley Community Center, 14068 Ranch Road 12.
Building on a drainage study the Guadalupe-Blanco River Authority began months before the Memorial Day weekend flood, the federal agency used streamflow velocity and volume data collected during the May 23 deluge to model flood risk, FEMA analyst Larry Voice told the Statesman. The Austin American-Statesman report continues:
The advisory maps, which will go through a yearlong review process, dramatically expand the floodplains along the banks of the Blanco River and tributary creeks through southern Hays County, the hardest hit area during the deadly Memorial Day weekend flooding. FEMA’s floodplain maps determine which property owners must buy flood insurance and how high they must build new construction for communities that participate in the National Flood Insurance Program …
The maps raise the base flood elevation — the minimum height for the floor of any newly constructed building — more than 8 feet in many areas, a major increase. Existing structures are grandfathered into floodplain rules, but any future construction would be governed by the new heights, requiring owners to be built on stilts or raise elevations through in-fill.
The costly requirements can lower property values, but they can also prevent tragedy during natural disasters by keeping residential structures out of harm’s way. The Deer Crossing Lane home in Wimberley that was swept off its foundation — leaving one survivor out of a group of nine vacationers from Corpus Christi — was built before the community joined the flood insurance program. Had it been built today, it likely would not have been permitted.
Full text of a statement released late Friday afternoon titled, “Hays County Statement on Federal Flood Map Changes:”
“FEMA, the Federal Emergency Management Agency, today released a significant amount of information regarding changes to the existing floodplain in parts of Hays County in the Blanco River basin west of San Marcos (not including the City of San Marcos).
“Hays County staff is actively reviewing the changes and comparing them to previous maps, historic flood data and existing development. Additional information will be shared as soon as that review process is complete.
“At this time, Hays County has not made a decision as to whether to use the advisory floodplain maps as regulatory maps, but would do so only after a full, public process. Whether the advisory maps are used for regulation or not, staff will make them available to the public as an additional data set to ensure citizens are as informed as possible during their rebuilding efforts.
“Anyone with questions about floodplain permitting or the National Flood Insurance Program should contact the Hays County Development Services Department at 512-393-2150.”
CLARIFICATION 9:34 p.m. AUG. 6: An earlier version of this story referred to Wednesday’s event as a town hall meeting Organizers are billing it as an open house.