Posted on April 29, 2019
A long-awaited dredging of Lake Linganore is set to begin in the coming months.
But first, a 300-ton crane will lift dredging equipment into Lake Linganore early next month.
Mike Marschner, special projects manager in the Frederick County executive’s office, said much of the work before the dredging equipment and pumping system is installed will include setting up the dewatering station and staging area for the crane to allow it to place the dredging device in the lake.
The crane lift will occur sometime between May 6 and May 8, he added.
“That 300-ton crane, it requires a permit just to get it in [the area],” Marschner said.
The project is expected to remove about 100,000 cubic yards of sediment from the lake, which serves as the primary source of drinking water for the city of Frederick. The process will include placing dredging equipment upstream from the Boyers Mill Road bridge.
The project, a joint effort between the county, city of Frederick and Lake Linganore Association (LLA), will cost roughly $18 million. The city is paying for half, with the county and the LLA each contributing about a quarter of the cost.
The Maryland Environmental Service (MES) is overseeing the project.
Craig Renner, senior director of communications for MES, said there is extensive staging, site preparation and equipment mobilization required for the project.
“The dewatering system includes screens, sand separators and belt filter presses, which remove nearly all solids from the dredged material. The remaining clear water is discharged back to the lake,” Renner said in an email.
MES will work with Frederick County to keep careful sampling of the water before and after dredging.
Kevin Sellner, a local algae expert and Hood College professor who holds a doctorate in oceanography, said it’s possible that Hood might work with the LLA to do more sampling.
Sellner and Eric Roberts, a volunteer with the LLA who focuses on water quality, said the dredging could increase the level of phosphorus in the water, and then increase algae growth that will make it unsafe to recreate on parts of the lake.
Marschner said the dredging will be in a concentrated area, so residents can still boat, kayak or take part in other water activities downstream from the project.
Sellner said the project will hopefully return the reservoir levels in the lake to provide more drinking water to the city of Frederick. He also said there appears to be enough water testing during the project.
The dredging will shift sediment to a dewatering station nearby, near Nightingale Beach. The dried sediment will then be used as landfill cover at the county’s Solid Waste Facility at 9031 Reichs Ford Road.
Roberts, a local environmental consultant, agreed. Hood would collaborate with the LLA to do more testing. The frequency is still being determined and would need to be approved through LLA leadership, but would add another layer of protection for the community’s residents, he added.
Much of the additional testing would occur downstream of the project, Roberts said.
“It’s definitely a belt and suspenders approach,” he said. “MES has a good plan in place, but a little redundancy, a little extra never hurt as long as it’s cost-effective and it helps improve the safety.”
Officials said the project is expected to be completed in late 2020. A winter shutdown is expected later this year, as the dredging equipment won’t work as well in cold weather.
As the project progresses, city officials will continue to test water as it makes its way through the city’s water plant.
“For the past two months we have been daily monitoring the phosphate level at our intake,” Lambert said in an email. “We will continue our seasonal microcytsin toxin monitoring at our Linganore Water Treatment Plant which began back in 2016.”
“For the record, we are testing samples of our untreated intake water and finished tap water monthly between April and October to ensure that algae toxins are not reaching our water customers,” Lambert added. “To date we have had zero detections in our finished tap water.”
Source: fredericknewspost.com
