Rehabilitation work on Rough River Dam is set to begin within the next month, according to the United States Army Corps of Engineers Louisville District (USACE).
The USACE hosted a meeting on Tuesday, March 25 at the Rough River Lake State Park Lodge to inform the public on why the rehabilitation work will be taking place and what changes can be expected while the work is going on.
USACE Louisville District Geotechnical Engineer Jeff Esterle gave a presentation on the project, which is estimated to take about three to five years to complete.
According to Esterle, in 2005, the USACE started screening its dams for safety concerns to determine which dams required immediate attention.
During this initial screening process, the USACE determined Rough River would need repairs but not right away.
Starting in 2008, the USACE started the study phase of the Rough River Dam repair project, which, over the next five years, would reveal “unacceptable risk” due to Rough River Dam’s foundation’s being constructed on karst geology (solutioned limestone), Esterle said.
According to Esterle, the karst foundations - which were found during the original construction of the dam but not determined a potential risk at the time - have the capability of eroding the dam’s embankment soil internally.
Karst limestone is a prevalent geological feature throughout the majority of Kentucky, so to avoid building on karst would have been nearly impossible, Esterle said.
A July 2012 Dam Safety Modification Report recommended major rehabilitation to ensure the dam’s structural integrity.
Currently, Rough River Dam is operating as intended with no issues, so the proposed work, according to Esterle, is a proactive approach to “fix these formations before they become a problem.”
The Dam Remediation Project has been divided into two phases. The first phase will begin this year with the relocation of State Highway 79 to the upstream slope to ensure uninterrupted traffic while dam repairs are taking place.
The relocation of Hwy 79 will be temporary, and after the project is completed, the highway will be restored to its original position. The temporary road will then be repurposed as a walking track for visitors to the dam, Esterle said.
The second part of Phase I will begin with the initial grouting. This will involve two rows of holes tightly drilled across the dam. Through these holes, grout (a soft concrete) will be used to fill in any cracks in the foundation, said Esterle.
Following the application of the grout, the USACE will then determine the necessity of Phase II, which will involve the installation of a cut-off wall if the grout does not prove to be a permanent solution.
If the grout will suffice, the dam rehabilitation project will be complete; if not, a cut-off wall will be installed to permanently repair the dam.
Esterle said the cut-off wall will likely be installed regardless of necessity to ensure the dam operates as intended for decades to come; however, approval will need to be granted by the state to do this. The installation of the cut-off wall is anticipated to begin in 2016 and end in 2019.
Changes to lake operations that would impact normal public use are expected to be minimal. The campground will likely be closed during the installation of the cut-off wall, but as aforementioned, this work will not begin for at least two years.
Rough River Lake Park Manager Diane Stratton said, “Right now we do not anticipate any change to our recreational pool.”
For updates as the Rough River Dam work progresses, visit the Rough River Lake Facebook page or the USACE website at www.lrl.usace.army.mil.