The results of a three-year floodplain study in Onion Creek by the Austin Watershed Protection Department is calling for voluntary home buyouts as the most effective solution to reduce area flood risk.

In May, the city gave a presentation to Onion Creek residents on the six flood-mitigation options that would protect homes and structures in the Pinehurst and Wild Dunes neighborhoods.

The options included a range of choices including channel clearing, building regional detention ponds and a voluntary buyout program.

The final analysis was released Tuesday, Oct. 31.

Based on the results of the analysis and the project scoring criteria, engineering firm Halff Associates recommended voluntary buyouts as the preferred flood mitigation alternative because it is the quickest and least expensive option, the watershed protection department said in a memo to Mayor Steve Adler and Austin City Council.

“The conclusion of the study is that a voluntary buyout options is the most effective flood risk reduction alternative for this area,” said Michael L. Personett, acting director for Austin Watershed Protection Department. “The Watershed Protection Department concurs with this conclusion and intends to proceed with a phased implementation of the buyout project.”

Personett added that, assuming 100 percent participation of property owners, the preliminary cost estimate for buyouts by the city is $77.5 million.

The Onion Creek Homeowners Association opposed the buyout project in a recent press release.

“We, the Onion Creek Homeowners Association, do not consider buyouts as flood mitigation,” said Mike Rodriguez, president of the Onion Creek HOA. “Buyouts do not prevent future flooding; their purpose is to reimburse those who have suffered major damage to their homes and to their lives with relocation money.”

Rodriguez added that buyouts do no cure lives and every effort possible should be made to mediate flooding in Onion Creek as it tends to create irreparable damage to the neighborhoods and also has major negative impacts for the city, such as lost property taxes.

“We ask that every effort be made to identify alternative solutions to mitigate future flooding before buyouts are employed as a last resort,” Rodriguez said.

The city will hold a neighborhood meeting before the end of the year to present final results and share detailed information about the project and buyouts.