Don’t panic, Austin officials said this week. The Waller Creek Tunnel works — just.
The American-Statesman broke the news this month that the $161 million project, designed to lift a swath of downtown out of the creek’s flood plain, has severe structural problems that could reduce its ability to control flooding downtown and lessen its lifespan, according to a letter city officials sent to its primary builder, S.J. Louis Construction, Feb. 23.
Officials said this week that the tunnel will do the job for up to a 100-year flood —despite their letter to builders last month that structural deficiencies impact “the entire purpose of the tunnel.”
But it’s unclear how much the flaws could affect capacity for floods larger than that or how much the deficiencies have shortened the structure’s lifespan.
The city wants to be paid back $22.3 million of the firm’s $48 million contract. The firm disputes the city’s accusations and instead sued, trying to halt a belated termination of its contract.
City staff members answered questions about the issue this week for the first time.
“We had our design engineers model the tunnel under its repaired condition, and it still safely passes a 100-year flood event,” interim Assistant City Manager Joe Pantalion said. “Therefore, it reduced the flood plain downstream of Waterloo Park, as anticipated.”
The tunnel, which began construction in 2011, flows from the southern side of Waterloo Park in a 1-mile channel to Lady Bird Lake. It is designed to siphon water up from the lake during dry times, to keep the creek flowing. During heavy rain, its flow reverses to provide a huge channel down to the lake, reducing downtown flooding and allowing development in what was previously flood plain.
On top of the 100-year flood specifications, the tunnel was supposed to have an added safety cushion of 3 feet of height around its primary inlet at Waterloo Park. Because of the construction issues, that cushion has been cut down to 1 foot, Pantalion said.
The height was lost because the contractor used poor quality concrete, missed a tunnel liner, and skipped and later replaced missing portions of rebar, creating a “patchwork of repairs,” according to the city’s letter.
That all means that, when it floods, water moves a little more slowly through the tunnel and backs up faster.
“What you want is a smooth, slick surface,” Pantalion said.
City officials haven’t analyzed how much of a difference that could make in cases of extreme floods, they said. Nor have they studied, yet, how the lifespan of the tunnel — intended to last a century — and future costs could be affected. But they suspect there will be an impact.
“It’s going to be stronger if it’s one solid piece, not a patchwork of repairs,” Public Works Director Richard Mendoza said.
In its lawsuit, S.J. Louis Construction accused the city of disrupting the project by failing to provide information, materials and access to the work area.
“Our position is that all of this, the whole process … was mismanaged by the city, and they’re trying to divert attention away from that,” said Tom Watkins, a lawyer for the firm.
The firm argues contract termination is a manipulative way for the city to seek damages that will unfairly hinder future bids. The city declared the contract terminated March 5, even though the tunnel has been finished for years.
S.J. Louis Construction filed an amended petition last week asking for a temporary and permanent injunction to undo that. The city responded Monday, arguing that it has governmental immunity from the suit.
City Council Member Kathie Tovo, whose downtown district includes most of the land in Waller Creek’s flood plain, said she is pleased with how staff has handled the matter, fighting for the city’s interests. The information she’s gotten since initially hearing of the tunnel’s flaws has made her more confident it still will perform, she said.
“It’s more the longevity of the tunnel that’s compromised,” Tovo said. “While that’s hugely disappointing, and I support efforts to hold the contractor accountable, I’m relieved the tunnel will live up to what we promised.”
Peter Mullan, CEO of the Waller Creek Conservancy, a nonprofit dedicated to redevelopment along the creek, agreed. He does not expect any impact to development of a planned parks system along the creek or to new development, as the 100-year flood plain estimates remain the same.
But he’s been fielding plenty of concerns since the city’s allegations about the tunnel became public.
“What we’re saying is what we’re saying to you, that the tunnel works,” Mullan said.