A three-man commercial dive team, hired by the Rock-Koshkonong Lake District (RKLD), conducted a search on Saturday (Aug. 24) of the Rock River bed beneath the County Highway M/F Bridge at Indianford.
According to RKLD Commissioner and newly appointed Dam Committee member Mike Shumaker, GOE, with Midwest headquarters in Davenport, Iowa, was hired, in part, after citizens living near the Indianford Dam and Bridge contacted RKLD board members, alleging, he said, “chunks of concrete were falling in (to the river)” while the bridge underwent deck reconstruction last year.
While there was some discussion about addressing the matter earlier, Shumaker said, “the water was high before, now it is lower so we can take a look.”
A dive team had been contacted to help with making some adjustments at the Indianford Dam powerhouse, RKLD Chairman Al Sweeney said. Commissioners agreed that it was logical to have that team investigate concerns raised by private citizens about debris which they said had fallen from the bridge into the river, he said.
According to Sweeney, a private citizen said concerns had been brought to the attention of the Wisconsin Department of Transportation (WisDOT), but there had been a lack of response.
A primary need for the dive team surfaced after RKLD commissioners declared emergency conditions in July, when one of the dam’s two wicket gates would not properly close. While an obstruction within the gate ultimately cleared, dam professionals consulted by RKLD suggested the dam’s wicket gates should be fully inspected. The process required “dewatering” the gates. Large panels were employed behind the powerhouse trash racks to hold back water, allowing at least one of the sealed turbine chambers within the powerhouse to drain. There were complications during that process, Sweeney said, necessitating help from the dive team.
The dive team’s services cost $3,000, and were approved as part of the emergency declaration, Sweeney said.
‘Piles of concrete’
Submerged in water beneath the bridge, the team found what GOE Dive Team Supervisor Mark Eubank described as “piles of concrete,” some with rebar attached, and metal pieces one of which was described as “a piece of angled iron and C-channel about 10 feet long.”
Describing the debris fields found below the bridge, dive team members said the riverbed adjacent to the east bank and in front of the dam’s six slide gates was “100 percent covered.” Riverbed underneath the middle of the bridge was “80 percent covered,” and bed under the west side in front of the Indianford Dam powerhouse was “50 percent covered.”
“It’s everywhere,” Eubank said.
Concrete chunks were arranged in piles, with pieces ranging from baseball to basketball size, he said.
Some had what he described as: “crazy rebar, it’s sticking out everywhere.”
GOE is expected to deliver a full report of its findings to RKLD in advance of its next monthly board meeting, scheduled for Sept. 19.
“Concrete is not supposed to be under the bridge. The material presents a safety hazard, impedes water flow and has negative environmental impacts,” Sweeney said.
The bridge spans the river upstream from the dam, positioned, in relationship to the dam, at an angle, with about 200 feet between the bridge and the powerhouse on the west bank of the river, and 80 feet between the bridge and the slide gates on the east bank of the river.
Sweeney described the underwater obstructions as “like having another dam in front of the dam.”
Sweeney said he plans to invite WisDOT to attend the next RKLD monthly meeting.
DNR has also been notified about the rubble under the bridge, he said.
RKLD will be looking to WisDOT for a plan for rubble removal, he said.
Sweeney said he had “no clue” what cleanup might cost.
“I’ve heard that the easiest way is to get a dive team with a boom, or wait until winter drawdown and have a barge with a backhoe. When you have 60,000 pounds on a barge in a river, it’s expensive, maybe $1,000 per day,” he said.
The six-span steel girder Rock River Bridge at Indianford was built in 1956. The project, begun last spring, was estimated to cost $1.9 million, and was funded 80 percent with federal dollars, and 20 percent through funding coming from Rock County, an engineer with the project’s design consulting company, K. Singh & Associates, told residents attending a public information meeting held at the Fulton Town Hall in the spring of 2017.
In 2017, work was outlined to include: replacing the full deck, installing new drains, repairing, cleaning and coating the steel girders, removal and replacement of concrete under the bridge, installing new railings, and replacing guardrails along the approach to the river.
A majority of the work was completed last October, Sweeney said.
This summer, the bridge was closed again.
In an email shared with the Milton Courier, Milwaukee-based Daar project engineer Teri Schopp said contractor (Black River Falls-based Lunda Construction) waited for high water levels to recede before making repairs to piers in the water.
During a telephone interview conducted in July, Lunda Construction Senior Project Engineer Laremy Sacia said the work entailed “patch work” in the form of surface repairs to structures located underneath the bridge.
Minimal Debris standard
In a telephone interview conducted Monday (Aug. 26), DNR Environmental Analysis Specialist Shelley Warwick said the department was aware that divers had found debris under the bridge, but was still investigating the circumstances under which it might have been placed.
When working with WisDOT, engineers and construction crews, she said, there are different levels of debris standards, including “minimal debris” and “no debris.”
“We are looking into it, but we think this project had a minimal debris standard,” she said.
To determine the standard, she said, DNR, WisDOT and project engineers look at issues of safety asking: “How do we get the debris captured? What’s reasonable in terms of safety?
“Concrete is sometimes 70-plus years old and it doesn’t break in predictable ways.”
She said DNR was looking into the matter with WisDOT and Daar Engineering.
“We are looking into it to see if they met the standard to the best of their ability,” Warwick said.
The dive team also aided in reconnecting a chain to a “dewatering plug” used to empty water from within a powerhouse turbine chamber housing one of two wicket gates. The gate had recently become blocked by debris, which was later dislodged, likely by water pressure, and expelled, returning the gate to its full range of operation, Sweeney said. Inspection of the gate was still recommended and steps were underway to perform that work, he said.
On July 17, hydro technician and Wild Rose Machine Shop, LLC, owner Chris Cutts was asked to assess the condition of the west wicket gate after it became unable to fully close. Cutts outlined a plan, involving the reinstallation of dewatering slide gates, which had earlier been removed, so that he could enter the sealed turbine pit through a 2-foot in diameter manhole and inspect the wicket gate for damage and maintenance. He said the gate was likely blocked by debris.
During the Aug. 10 RKLD annual meeting, former RKLD Commissioner Ray Lunder told the Milton Courier that the debris within the west wicket gate had dislodged.
During his assessment, Cutts advised RKLD board members that the wicket gates within both turbine pits should be inspected as a matter of maintenance, and the west turbine gate should be further inspected for potential damage sustained during the blockage.
Three dewatering slide gates were recently placed in front of the west turbine chamber in the powerhouse to block river water from entering, Sweeney said.
A manhole and shaft leading into the pit is approximately 16 feet deep, and there is still about 12 feet of water inside, Sweeney said.
On Saturday, the dive team reattached the chain to the plug, Sweeney said.
“We did get the chain connected to the hinged cover (of the plug) and we did get it open. We fastened it wide open,” he said.
Sealing the dewatering gates is the next step, Sweeney said.
Sweeney also described a section of trash rack that had been removed from the west side of the powerhouse. With the dewatering gates in place, debris could not pass through into the turbine pit on the west side, he said. The rack was removed because it was damaged. The section, a 3-foot by 10-foot panel, was twisted, and not staying properly in place, he said.
He said the damaged section could have been responsible for allowing passage of the debris, which had earlier obstructed the wicket gate.
Cutts will be coming to assess the situation sometime in the next week, Sweeney said.