After heavy rains overnight Friday filled Cascade Lake to the brim by Saturday morning, Carroll County officials cautioned that an uncontrolled breach of the lake’s dam, and thus further flooding, was possible.
However, because engineering crews were able to lower the water level significantly throughout the day, officials’ concern was lessened by the evening.
“It’s down about 1.5 to 2 feet today,” Carroll County Sheriff’s Office spokesman Timothy Brown said of the lake’s water level at about 6 p.m. Saturday.
Although crews continued to pump water from the lake Sunday, according to a Sunday evening news release from the Sheriff’s Office, a controlled breach of the dam is being planned tentatively for Monday morning. A controlled breach would allow more water to flow downstream, relieving water levels at the lake but risking flooding downstream.
“During excavation of the dam, there remains a hazard of a dam failure so area residents are advised to remain vigilant and aware,” the news release said.
In a Saturday morning news release, Brown said the overnight rains had both filled the lake and damaged the dam, such that people living along the tributary of the east branch of the Patapsco River should be ready for large volumes of flowing water and possible flooding, should a breach of the dam occur.
Snydersburg Road between Cape Horn Road and Hampstead Mexico Road/Md. 482 was closed to traffic due to the overflowing lake and potential for flooding, while reverse 911 calls and door-to-door visits were made to people living in downstream areas, according to Carroll County Sheriff Jim DeWees.
“Early on we were panicking a little bit, because it was really over the top and had exceeded the lake’s capacity, there were no two ways about it,” DeWees said. “But folks stepped up and were able to get additional pumping equipment out there.”
That work had progressed well enough that a Carroll County government news release Friday night said the immediate threat of flooding was reduced and lake levels were then low enough for a controlled breach. “Plans for the dam breach were developed by the property owner’s engineers, and have been reviewed and approved by the Maryland Department of the Environment’s Division of Dam Safety,” the release said.
After bringing in an additional engineering company to pump more water from the lake and lower the water level Saturday, the plan for a controlled breach is now back on, tentatively for Monday, according to Brown. It depends on whether pumping can reduce the water level further by that time, he said, as it is still too high to engineer a controlled breach.
Larger barriers — basketball-sized boulders in clusters inside wire mesh — are also being placed downstream of the dam in order to slow the flow of water as it is released, both during the initial controlled breach, when it occurs, and for the future, according to DeWees.
Out of an abundance of caution, Brown said, law enforcement officers and road crews will remain in place to close down roads in the area that would be affected by an uncontrolled breach, should it occur, including:
Snydersburg Road and Cape Horn Road
Brodbeck Road by the Walmart
Brodbeck Road, Walmart side at #1517
Brillhart Road and Md. 482
Brodbeck Road and Schaeffer Drive
Md. 482 and North Brook
Shiloh Road and Brodbeck Road
Cape Horn Road and Brillhart Road
Harvey Gummel Road and N. Cape Horn Road
Md. 30 Bypass and Md. 482
Snydersburg Road between Cape Horn Road and Hampstead Mexico Road/Md. 482 has been and will remain closed, Brown said.