Project Overview
Project Status
Floodplain Changes
Areas with Many Structures Moving into the Floodplain
Areas with Many Structures Moving Out of Floodplain
View the Maps (as PDFs, on a Interactive Map Viewer or Hard Copies)
Project Details
More Information

Austin is in the middle of Central Texas' Flash Flood Alley, one of the most flood-prone areas nationwide. If you live or work near a creek, your home or business may be at risk for flooding. That's why FEMA's project to revise their floodplain maps is so important. The new maps are based on up-to-date information and locate the floodplains more accurately than the current maps. FEMA will use the new maps to determine rates for flood insurance.

The maps will become effective on September 26, 2008. This date is confirmed and will not be delayed again.

The new maps show changes in the floodplain. Due to the City of Austin's flood control program, many homes and businesses are no longer in the floodplain. However, the new maps also show that some homes and businesses are now in the floodplain that were previously thought to lie outside it.

To find out if your property is affected, call your insurance agent or look your property up on the new maps. Due to limitations in technology, the City of Austin is not able to generate a mailing list of properties affected or directly notify property owners. Instead the City held a series of public meetings in 2006 when the maps were first released and has periodically run advertisements about the new maps.

There are properties throughout the city that are now considered in the floodplain, but the areas listed below have many structures newly in the floodplain.

• Williamson Creek Watershed - between S. Congress Ave. and Emerald Forest Dr., near Oak Hill Pond, near Covered Bridge Drive, near Highway 71 and along Fair Valley Trail
• Carson Creek Watershed
• Country Club East and West Watersheds
• Fort Branch Watershed
• Slaughter Creek - along Canon Yeomans Trail
• Tannehill - a few commercial structures near Highland Mall.

Those with property newly in the floodplain should consider buying flood insurance by August 11, 2008, forty-five days before the new maps become effective, to receive a better rate both this year and in future years. For additional information concerning the effect of the new maps on insurance rates, please see www.floodsmart.gov. Mortgage companies generally require flood insurance on properties in the floodplain.

There are properties throughout the city that are no longer considered in the floodplain, but the areas listed below have many structures taken out of the floodplain. Often this is due to City projects designed to prevent flooding.

• Boggy Creek Watershed - along Clarkson Ave.
• Dry Creek North Watershed - upstream of FM 2222 and west of MoPac
• E. Bouldin Creek Watershed
• Fort Branch Watershed - near E. 51st St. and Norwood Road
• Little Walnut Creek Watershed
• Shoal Creek Watershed
• Slaughter Creek Watershed - along Tecate Trail
• South Boggy Creek - near Seminary Ridge Drive
• Tannehill Branch Watershed
• Waller Creek - near Chesterfield Ave.
• Walnut Creek - in the Crystalbrook Subdivision and near Johnny Morris Road.
• Williamson Creek Watershed - Creek Bend Subdivision

You may view the new maps as pdfs or in an interactive map viewer. Hard copies are also available at the Watershed Protection and Development Review Department's Development Assistance Center, first floor, One Texas Center, 505 Barton Springs Road, Austin, Texas 78704. In addition, the Ruiz and Windsor Park libraries have hard copies of the original preliminary maps. The copies in the two libraries do not reflect the July 2007 revisions.

Most of the current FEMA floodplain maps in Travis County are based on out-of-date technical data prepared up to 29 years ago. In October 2003, FEMA initiated the Travis County Floodplain Map Modernization project. In early March 2006, FEMA, the City of Austin and Travis County released preliminary new digital floodplain maps and models for an initial public review and comment period. The new maps show the 100-year and 500-year FEMA floodplains and the 25-year and 100-year City of Austin fully-developed floodplains in Travis County. The FEMA floodplains will be used for insurance rate purposes and are based on existing watershed land-use conditions. The City of Austin floodplain maps and models show the anticipated, fully developed land-use conditions; these floodplain maps are used for land development regulation and floodplain management purposes.

FEMA received 21 technical appeals and protests to the preliminary maps during the 90-day comment period in 2006. As a result of these appeals, the agency issued revised maps for the Fort Branch, Shoal, West Country Club (Tributaries 1 and 3) and Williamson watersheds on July 11, 2007. There were no comments on the revised maps.

FEMA initiated and manages the mapping project in association with the City of Austin, Travis County, eleven other Travis County communities, the Lower Colorado River Authority, the U.S. Army Corps of Engineers and the State of Texas. The project entailed the development of GIS-based hydrologic and hydraulic models and floodplain maps of many watersheds in Travis County. Because of its susceptibility to flash flooding and its rapid growth, Travis County was one of the first counties in the nation chosen by FEMA for participation in its Map Modernization Program. The program includes the development of digital flood insurance rate maps. Digital Flood Insurance Rate Maps will replace the current (paper) Flood Insurance Rate Maps and will include database information related to the underlying base maps and technical data.

All or portions of the following watersheds were included in the detailed study effort: Colorado River, including Lake Travis; Lake Austin and Town Lake; Boggy Creek; Blunn Creek; East Bouldin Creek; West Bouldin Creek; Walnut Creek (including Little Walnut and Buttermilk Creeks); Onion Creek (including Slaughter Creek, Marble Creek, South Boggy Creek and Williamson Creek, with Sunset Valley Tributary, Kincheon Branch, Pleasant Hill Tributary and Cherry Creek); Johnson Creek with Possum Trot Branch; Dry North Creek with four tributaries; Harris Branch with four tributaries; Shoal Creek; Carson Creek; Fort Branch and Tannehill Branch of Boggy Creek; West Country Club Creek and East Country Club Creek; and Waller Creek.

All other Travis County watersheds were remapped using the City of Austin's 2003 topographic data and existing FEMA floodplain models. Please visit www.halff-femastudy.com to view maps showing the watersheds studied.

More information about this project is available on the Travis County Floodplain Studies/Mapping Project Presentation (pdf).

If you have questions about the new maps or the approval process, you may contact the City of Austin's Floodplain Management Hotline at (512) 974-2843 or e-mail us.

For more information about the technical aspects of the remapping project, visit www.halff-femastudy.com or contact Halff Associates, Inc. (FEMA's study contractor for this project) at (877) 425-3389.

For more information about FEMA and floodplains and flood insurance, visit www.fema.gov/fhm/fq_term.shtm, or contact the FEMA Region VI office at (940) 898-5127.