Work has started at Grenada Lake, and the U.S. Army Corps of Engineers (USACE) will spend the next few weeks inspecting structures.
Throughout the week, workers with the USACE completed the building of a cofferdam across the spillway and pumped water out where dam structures are located as part of the dam inspection, which is done every five years.
Grenada Lake Natural Resources Specialist Chris Terry said the next step would be cleaning debris from the lake floor.
“We will bring in the skid steer for the next few days to get the floor completely dry,” Terry said. “There’s also a lot of debris that we have to remove. After that we will start looking for any repairs that need to be made.”
The Corps also got help from some of the local men who walked the shallow waters removing old fishing lead, likely for their own personal use.
During this dewatering period, the stilling basin will be pumped dry behind the earthen cofferdam so that routine repairs can be made to the outlet works conduit, relief wells, and stilling basin.
After the water is pumped out, crews will inspect the 14 concrete baffle blocks, which are normally underneath water and used to break the force of the current coming out of the dam. This is where the officials will check the blocks for basin floor damage, a process that Terry calls vital.
“The force that comes off those blocks can wear on that concrete,” Terry said. “Something as small as a washer from a fishing line can make a large hole over time.”
The inspection is expected to last approximately four weeks, depending on the necessary repairs that are required.
Periodic inspections are routine dam inspections performed every five years by multidisciplinary engineering teams to ensure operational integrity, structural stability, and dam safety, as required by the USACE regulations.
According to Terry, this is the 11th quinquennial inspection conducted on the Grenada Dam since it was placed in operation in 1954.
The last inspection was Sept. 2015.
USACE Vicksburg District are conducting scheduled maintenance and inspections at two other of its north Mississippi lakes - Arkabutla and Sardis - that have temporarily closed each lake’s outlet gates from approximately mid-August through the end of September.
Additionally, Sardis Lake’s three lower lake beaches - Paradise Point, Main Beach and Cypress Point - will be closed to swimming.
The periodic maintenance and inspection of flood control structures helps ensure that the overall flood control system continues to function as designed. The structures at Arkabutla, Sardis, Enid, and Grenada lakes control drainage for approximately 4,425 square miles in north Mississippi.
Once the necessary repairs are performed, a team of various engineers from the Vicksburg District Office will thoroughly inspect the repairs made as well as all facets of the dam and related structures.
“We just want people to pay attention to the roped off and barricaded, restricted area when this process begins,” Terry said.
Several people lined outside the restricted area and watched crews work inside the spillway. It’s a scene that many of them don’t get to see that often. Some even see it as an opportunity to grab a few fish.
“I’m just waiting to get down in there,” said Harold Steen of Bruce. “As they pump more and more water out, you can see some of those big catfish jumping around in there.”