LB dam replacement on schedule

By Anna Jauhola
The dam replacement project at Lake Bronson is still on schedule to be completed by late 2027. The massive undertaking has been in progress since November 2024, and at one point was actually ahead of schedule. But, this summer, as Ames Construction was digging to prepare for concrete work on the spillway, they ran into high groundwater.
Ames has used pumps to keep the water out while the crew works on laying materials to prepare for, and while pouring, concrete.
Despite that hiccup, the project remains on schedule and the hope is to have water running through the new dam sometime next year, said Dan Caron, field representative for Barr Engineering.
“We’ve got the bridge abutments in too, essentially they are what the bridge sits on,” Caron said. “And this fall we’ll set the girders too. Then we’ll come back in the spring and pour the deck on it.”
The new dam structure is 138 feet wide, compared to the original dam that was about 60 feet wide. The construction crew is also currently building the weir portion of the dam. Using rebar in a frame, they are creating the formations for pouring the concrete weir, which looks like a zig-zag from above.
There will be seven triangles on the weir, which creates more area for water to flow over. This not only allows for continuous flow over the dam, but creates a safer situation for park personnel. The original dam had three manual gates that park officials had to open and close on a catwalk above the dam, especially during a heavy rain or flooding event.
Now the only thing park staff will have to do is electronically open or close a gate situated at the bottom of the new dam from a location on top of the dam.
That gate is on a low-flow pipe that will release water into the bottom of the new spillway.
“This is how I used to start my day and this is how I would end my day,” said Tim Williamson, Lake Bronson State Park manager. “And this is how I would be in the middle of my day. I would take walks, checking things at the dam, especially the northern wall.”
On days like Friday, Sept. 12 when the area received 1.5 inches of rain overnight, and areas to the east received 3.5 inches or rain, Williamson and his staff would have been on high alert. He added he’s definitely the biggest fan of the project.
“When you stand here, the bridge would be moving slightly,” Williamson said as he stood at the east edge of the original dam’s bridge. “Like last Fourth of July, when I was standing out here at 11 at night, during a lightning storm, trying to take the gates up and then keeping my head down just behind the poles. At least there’d be something above me and I would be able to mostly walk away.”
He is happy that how he monitors the new dam structure will be completely different.
Once the weir is complete, the next step for Ames is to get the coffer dam in place and complete the demolition of the original dam structure. Existing materials taken from the area will be used to fill in the hole left by the original dam, Caron said. Then Ames will have the rest of the seepage cutoff wall installed. This wall will be at varying depths between 70 and 90 feet, and extend to the south as far as the current dam parking lot.
The plan is to have water flowing through the dam on schedule sometime next year. Then the rest of any spillway work will be completed and the road and bridge above would be built.

THE LAKE BRONSON DAM abutments have been poured and the crew is working on the girders, along with the spillway. The structure is 138 feet across.
(Enterprise photo by Anna Jauhola)

A CREWMAN STANDS ATOP one of frames for a portion of the weir structure on the Lake Bronson dam.
(Enterprise photo by Anna Jauhola)