A Pennsylvania American Water project at the No. 7 Reservoir in Dunmore is causing sediment to flow into Roaring Brook.
Brown muddy water is then finding its way into the Lackawanna River at its confluence with the stream in South Scranton, impacting aquatic life in both waterways.
"It's like you bring a cement truck up to your dining room window and you just fill your dining room into your living room into your bedroom and your kitchen with cement," said Bernie McGurl, senior project manager for the Lackawanna River Conservation Association (LRCA). "That's sort of what's going on, on a macro scale on the bottom of Roaring Brook and the bottom of the Lackawanna River over the next several months.”
The water company began work on the $17 million dollar rehabilitation project in October, said spokesperson Susan Turcmanovich. Two large valves were opened to lower water levels in the 138-year-old reservoir, she said. Upstream sediment from Roaring Brook began to flow through the valves.
"It's unfortunate that we have a case study in what can happen when you don't prepare for this kind of sediment load when you do dam work," said Tara Jones, executive director of the LRCA.
The LRCA estimates the issue began over the weekend.
Turmanovich said PA American Water is currently working with the Pennsylvania Department of Environmental Protection (DEP) to stop the flow of sediment. Smaller rock dams were already installed, she said, adding contractors will be onsite this weekend to construct a larger riprap dam, four-feet high, across Roaring Brook. One of the valves will be closed.
The dam was built in 1886 by the Scranton Water Company, McGurl said. Since then, there have been numerous hurricanes, thunderstorms, downpours and blizzards.
Roaring Brook is very steep, he said.
"It can move a lot of sedimentary material," McGurl said. "It built up a layer of approximately 20 to 30 feet deep of mud and silt and sediment and sands and gravels and cobblestones, but a lot of fine particulate sediment."
The utility company’s engineers and project designers miscalculated, said McGurl.
“They should have anticipated that they might need to manage the sediment in the bed of that reservoir," he said.
The dam structure at the reservoir is considered a high hazard dam because of its age, said McGurl. State law requires that dams are inspected and certified every few years. Older structures either have to be rebuilt or taken down.
It is being upgraded for stability and to continue to meet DEP regulations, said Turmanovich.
The LRCA has received reports that the sediment is making its way into the Susquehanna River in Luzerne County, said McGurl.
“The river will recover," he said. "But depending on how much sediment continues to be distributed in the habitat, and how long that that occurs for, that's going to mean a longer recovery time for the fisheries and macro invertebrate community.”
While the LRCA is disappointed, McGurl said the most important thing is that they solve the problem.
Jones said they are looking forward to touring the dam and helping clean up the sediment.
"We just want to see this be prevented from happening again in the future," she said.
