Floodplain


The National Weather Service and NOAA conducted a rainfall study, Atlas 14, across the nation to measure the intensity of rainfall and update our knowledge of flood risks. Based on this study, each region in the U.S. has been given updated information with the intention of directing city planning and risk management. The Atlas 14 study reveals that Central Texas region will experience greater, more intense rainfall events that may lead to property loss/damage.
The City of Austin Watershed Protection Department proposed a new City ordinance that would serve to 1) Adopt the data from the Atlas 14 study as a legitimate tool for future regional and city planning, and 2) Revise City Code (including the Land Development Code) for properties that the City determines are at increased risk based on the information in the Atlas 14 study.
In July of 2019, neighbors became aware of the possible impacts to the neighborhood of this study, including an increase of properties being moved into regulatory floodplains and restrictions on future improvements to properties, and requested more information from the City. Working with the Brentwood NA Steering Committee, District 7 Council Member Leslie Pool’s office agreed to hold a D7 Townhall meeting in August on this issue. The townhall was well-attended and allowed neighbors in Allandale, Brentwood, Crestview, Rosedale, and Wooten to hear the proposed changes from the Watershed Department. Click here to view the Watershed Protection Department’s presentation on Atlas 14.
Once the impacts were clearly identified (see list below), a group of neighborhood advocates organized and began to tackle the issues (advocacy efforts in red below). 
1. Properties from previously unverified 500-year floodplains would automatically be moved into the 100-year floodplain, resulting in a requirement to purchase FEMA floodplain insurance and adhere to city regulations restricting improvements.
Professional engineers challenged the hydrological models being used by the City and successfully proved the inaccuracy of the models, resulting in a majority of the properties remaining in the 500 year floodplain, and not being moved into the 100 year floodplain.
2. Properties previously identified in the 100-year floodplain (many of which were identified as recently as 2016) would move into the 25-year floodplain. Current City Code prohibits any improvements to properties that encroach on the 25 year floodplain.
Properties that would be moving into the 25 year floodplain were at risk of turning over to developers who would find it more cost-effective to raze lots and build larger homes at a higher elevation (vs. elevating the existing structure to meet the proposed requirements). Neighbors successfully argued that existing structures could remain at current elevation, while additional improvements would need to comply with a stricter building standard (elevation of additional improvements), preventing displacement of middle-income families from the City.
3. Interim maps would be used to enforce city regulations, effective immediately, on the above-stated properties until formal adoption of the maps by FEMA in 2-3 years.