Carroll County set out to rid itself of an invasive species about eight months ago, and now it appears the zebra mussels in Hyde’s Quarry have died off.
In March, the Board of County Commissioners approved nearly $350,000 to eradicate zebra mussels from the Westminster quarry. Last week, bags containing about 4,500 zebra mussels were pulled from the quarry to see whether the potassium chloride pumped into the water had the desired effect, according to Tom Devilbiss, director of land and resource management.
Potassium chloride essentially suffocates the mussels, Devilbiss said, and the concentration placed in the quarry is not harmful to other animals or humans.
The county bought Hyde’s Quarry, along Jasontown Road, in 2008 as a potential drinking water source, then divers from the Maryland Department of Natural Resources found mussels in the quarry in 2018, according to Devilbiss. The mussels had to be killed because they reproduce quickly and clog pipes, he said.
“They’ll get into pipes or pumps and they’ll clog everything up," Devilbiss said. “We didn’t want them spreading.”
Carroll County contracted with ASI Group, based in Canada, to tackle the issue, he said. Zebra mussels are more commonly found to the north, so Hyde’s Quarry is a bit of an anomaly, according to Devilbiss.
“This was the only water body, exclusive of the Chesapeake Bay, in Maryland where they’ve been found," Devilbiss said. He did not know how the zebra mussels came to be in the quarry.
Months ago, divers retrieved zebra mussels from the water, which were then put into bags and hung from buoys at three different depths at 15 locations in the quarry, according to Devilbiss. Those bags were removed and the mussels were examined Tuesday, Devilbiss said.
Devilbiss and Commissioner Eric Bouchat, R-District 4, inspected the progress of the eradication effort.
“None of them survived,” Devilbiss said.
Follow-up sampling will be conducted, but Devilbiss is hopeful the preliminary results are indicative of the remaining zebra mussel population’s status. Devilbiss said the empty shells will remain in the water, as they will have no long-term impact on the water quality or its use. With no life inside the shells, they cannot reproduce and attach to pipes to clog them.
Though the mussels were discovered in the spring of 2018, Devilbiss said it took about a year to start eliminating them because the county needed special permits from the Maryland Department of the Environment. The county also required time to establish what type of techniques should be used for the project, he said.
The potassium chloride levels will be maintained to prevent further infestation, Devilbiss said, and the treatment should last for years. There is no set time for when the quarry’s water will be used for drinking water, but before that time comes the water will be purged of potassium chloride before people can drink it, he said.