PURVIS, Miss. (AP) - When it comes to the Lake Serene system and its dams, the fix appears to be in.
Or at least, on the way.
Potential solutions for problems at the earthen bulwarks holding back the waters of North Lake Serene and Oak Grove Lake are looming on the horizon, with work likely beginning sometime this summer.
Lamar County engineer Don Walker, who is consulting with the Lake Serene Property Owners Association, said he will meet with Mississippi Department of Environmental Quality in Jackson next week to “fine-tune the scope of the work” on both dams.
“There is not a time schedule set at this point, but I’m assuming within the next couple of months, some resolution on a final plan will be formalized,” Walker said.
That’s good news for Lake Serene residents, though the likely repairs and modifications for the two dams won’t be cheap.
Recently, Lake Serene property owners voted to accept an assessment of $2,921 per lot to pay for the bill that has been estimated to run as high as $1.65 million.
“I think we’ve included some of our engineering costs in that figure, but that’s about what we’re anticipating,” Walker said. “We’re hoping it will come in less than that, depending on what contractors will bid and how many will bid.”
LSPOA President Peggy Moore said that 64 percent of more than 500 lot owners in the Lake Serene subdivision voted to accept the assessment.
“We were very pleased with the majority, but (there’s been) all sorts of reactions, as you can imagine,” Moore said. “We all have different ideas, different ways of doing things, but as a whole, Lake Serene owners have come together to keep our subdivision up to the standards we have valued and invested in.”
That assessment will be paid in one sum or over a period of months.
“The timeline on the repairs prohibits spending payments over a number of years,” Moore said.
Walker said MDEQ has been involved since the initial events and any remedies have had to meet the department’s requirements and standards.
The first event dated back to late summer 2012, when Hurricane Isaac spawned storm systems that dumped more than a foot of rain on the Pine Belt.
The heavy rains saturated the earthen barrier between Oak Grove and Stump lakes, causing about a 100-yard section of the downstream embankment to slough off like heavy icing sliding off a slanted slice of cake.
A jagged surface crack had extended to the western edge of now-closed Buccaneer Drive, crumbling long sections of the asphalt edge of the road.
The dam never breached, but the weakened area was a major concern. Buccaneer Drive has remained closed and water levels in the lakes have been lowered to take pressure off the embankment.
Walker said next week’s meeting not only will firm up any steps to be taken, but also potentially pare down a list of potential repairs.
“MDEQ has allowed us to consider the possibility of raising the dam slightly, but we don’t want to do that if it’s going to negatively affect properties around the lake,” Walker said. “We have surveyed properties around the lake, and we are making that determination as to how high, if any, we could raise the dam.”
Walker said adding to the top of the dam would increase the barrier’s ability to prevent a “major overtopping” during a major weather event.
“In addition to that, (MDEQ) wants us to flatten the downstream slope, which would require a decent amount of fill material and we would have to do it in a specially-type way,” Walker said.
He said the repair would require a “benching” of the fill starting at the base of the dam, creating a terraced appearance as the work continued toward the top of the structure.
“They would have to do the fill in a specific manner,” Walker said. “They just won’t be able to start at the top dump the material down. They will have to start from the bottom, bench it in on a level area so they can compact it. It will almost be like steps, and then you would come back in and fill in the steps.
“We would have to lower the lake and drain it down to where we could get in there and work. It’s already down a good bit, the Stump Lake section, but all of that will have to be worked out in the schedule, when it can be done, time-frame wise, and it may be that it works out better toward a summertime construction period.”
The Lake Serene North problem was discovered on the morning of Oct. 16 when water was discovered flowing from under the apron of the dam’s spillway.
The dam sits about 100 yards from U.S. Highway 98 West
More unsettling was a small, vertical column of water carrying sand particles from beneath the spillway, known as a “boil.”
Since then, the level of the more than 100-acre lake gradually has been lowered about 6 feet to 7 feet. That eliminated the “boil,” and Walker said seepage “was much slower” since the lake was lowered.
“We have sent (MDEQ) the final recommendations on improvements at this point, but we’re still looking at this as probably a filtration system on the downstream slope,” Walker said. “Everything points to it at this time.
“(Construct an) underground filtration system, and get some graded material in there to minimize any movement of (current soil). Everything, it all points to seepage under the dam, and it also appears that it has been going on for a long time. I think we can address it with this, but we’re going to coordinate it with MDEQ to come up with the final, actual plan.”
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Information from: The Hattiesburg American, https://www.hattiesburgamerican.com
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