Flood Hazard Update | LCRA Flood Hazard Update | LCRA

Flood Hazard Update for Areas Between Buchanan Dam and Inks Dam

In September 2020, LCRA released a floodplain study that provided the most updated, detailed information available about flood hazards between Buchanan Dam and Inks Dam. The study will result in changes to the floodplain between Buchanan Dam and Inks Lake, moving some areas into the floodplain for the first time and other areas out of it. It also identifies a floodway along Inks Lake for the first time.

LCRA commissioned the study with approvals from Burnet and Llano counties. The study used the latest available digital terrain data and flood modeling methods to track where water released from Buchanan Dam travels during floods. The model results were confirmed by observations during flooding in 2016 and 2018.

The study updates flood hazard information in two areas:

  • The north side of Inks Lake in Burnet County, where water flows from the 14-gate and 16-gate sections and spillway of Buchanan Dam to Inks Lake. The old information was not based on detailed analysis and showed only approximate boundaries of the flood hazard areas. The new information better identifies where water will flow and for the first time identifies how high the water will rise during 50-, 100- and 500-year floods in these areas.
  • Along the length of Inks Lake in Burnet and Llano counties, from Buchanan Dam to Inks Dam. The new information identifies a floodway in this area for the first time. A floodway is the central portion of the 100-year floodplain, where flows are stronger and faster. The floodway on Inks Lake includes the central channel of the lake and some portions of adjacent land that are within the 100-year floodplain.

LCRA submitted the updated flood hazard information to the Federal Emergency Management Agency for approval in the form of a Letter of Map Revision. Upon final approval, FEMA will use the information to update its Flood Insurance Rate Maps. Communities use these maps to determine flood insurance needs and regulate development in flood hazard areas.

Next steps

After Burnet and Llano counties have notified affected property owners by certified mail, FEMA will publish notices in local newspapers. Property owners and the public will have 90 days to appeal the technical basis of the updated flood risk maps. The revised maps will become effective 30 days after the appeal period ends and all technical appeals are resolved.

Contact LCRA at [email protected] for technical questions about the study.

Contact Burnet or Llano county floodplain administrators for questions regarding floodplain management regulations and impacts on properties in those jurisdictions: