Two of many homes on Williamson Creek that flooded on October 17, 1998. Austin emergency workers responded to about 400 high water and rescue calls and evacuated about 300 residents in six neighborhoods during this storm.

The U.S. Army Corps of Engineers in partnership with the City of Austin is taking a second look at flooding along Williamson Creek. This evaluation will build on information that was gathered during the original feasibility study completed in 2006 and will include additional public input.

The original study recommended modifying the channel of Williamson Creek and restoring parts of its ecosystem. However, due to the cost of land for ecosystem restoration, the Corps deferred the project for further study, rather than seeking Congressional approval of the Williamson Creek project.

Features of the Study
Although the current study will build on the original one, there are several important differences based on public input:

• It will not include any structural solutions for the Broken Bow area.
• It will expand the project to include Cherry Creek up to William Cannon Drive Dr., an area that experienced significant flooding in October 1998 and November 2001.
• It will gauge the environmental impact of any modifications to the channel of Williamson Creek using the City of Austin's own strict environmental criteria.
• It will use the newly updated 2006 floodplain model as the basis for evaluation.
• It will evaluate bridges to assess the potential to reduce traffic hazards due to flooding as well as flooding upstream of the bridges.
• Based on excessive land costs and public input, there will be no trails or ecosystem restoration as part of this project.

Public Presentations
The City of Austin has made a presentation about the proposed study to the Environmental Board. There will be meetings to present findings and get feedback from the affected neighborhoods later this year (2008).

Background
Several neighborhoods in the Williamson Creek floodplain between S. Congress Ave. and Westgate Blvd. experienced significant flooding in 1998 and 2001. After the 1998 floods, the City of Austin requested federal assistance to help with flooding in these areas as well as in the floodplain of Onion Creek. The U.S. Army Corps of Engineers undertook a feasibility study that was completed in 2006. The Corps sought and received Congressional approval for the Onion Creek recommendations, but decided to defer the Williamson Creek project for further study.

Why Did the Corps Defer the Original Williamson Creek Project
The original Williamson Creek feasibility study was tied to a larger, regional effort for flood control, and the Corps was concerned that including the Williamson Creek portion would jeopardize approval of the whole effort. The concern was related to an updated cost estimate for the Williamson Creek project, which indicated that the cost of land for the ecosystem restoration component of the project far exceeded the target percentage set by the Corps. The original cost estimate was based on the Travis Central Appraisal District valuations while the most recent estimate was based on the market value of real estate in the project area, resulting in the estimated cost of the Williamson Creek project increasing from $4.4 million to $17.9 million.