Aweak point near the low water dam that forms Lake Brazos through downtown Waco is set for $9.1 million in repairs expected to start by the fall.

If the earthen embankment on the eastern bank near the low water dam were to fail, the river could largely bypass the dam, causing the water level to drop through town. The city has reinforced the embankment with steel, riprap and other materials over time, but it has needed reinforcement since the dam was built in 2007, officials said. Utilities Director Lisa Tyer said the project is tentatively set to begin in October and end in 2025.

The Waco City Council voted Tuesday to approve a contract with McMillen LCC for the $9.1 million project, after a detailed presentation from Freese and Nichols engineers and city utilities officials.

“This dam is really what makes your town lake,” Freese and Nichols engineer Victor Vasquez said. “If you lose that embankment you lose the lake, and the cost of repairing is significant if that were to happen.”

Waco City Manager Bradley Ford introduced the item as a “dam fine presentation” which drew laughter, groans and at least one “oh come on” from the audience, mostly city staff.

Vasquez, who has spoken to the council on the topic before, said Freese and Nichols does not know how the embankment was first built in 1985.

“The structure is standing, but the point is you have a risk here for failure if conditions are right,” he said.

About $7 million of the construction costs will come from water bonds the city issued last year, and the remaining $2 million will come from the water department’s capital improvement program plan.

Vasquez said the city built an early dam at the site in 1970, then modified it in 1985 because it was prone to getting jammed by brush and logs during every heavy rain. The city replaced it entirely in 2007 with a labyrinth weir design suggested by the U.S. Army Corps of Engineers.

Freese and Nichols designed the new dam. In the last leg of the project, the Brazos River flooded and damaged the earthen embankment, taking a noticeable chunk out of its slope that was still plainly visible in current photos included in the presentation.

Waco City Council voted against rebuilding the embankment at the time of the dam construction, and the embankment continued to take damage during floods in 2015, 2016 and 2018, according to the city. In 2017, Freese and Nichols evaluated the embankment, found it was unstable and recommended repairing it.

Tyer said a sinkhole appeared in the embankment in 2019, and Deputy Utilities Director Charles Leist stayed awake overnight until the city repaired the damage.

The project also will include reconstruction of the dam’s outlet works, which allow water to be diverted for dam maintenance. Elements of the outlet works pass through the embankment that is being repaired.

The outlet works on the eastern side were built by local engineer F.M. Young as a bypass system he wanted to use to generate hydroelectric power.

“That never came to fruition, but he did add a nice feature to the dam,” Vasquez said.

Rebuilding the outlet works on the east side will involve replacing steel pipes, creating a new concrete basin and moving some of the infrastructure to a higher elevation to prevent it from going under during floods.