SCRANTON — Whether caused by storm or man, the muddying of Roaring Brook in Dunmore and Scranton has sediment removal underway to clean up recent major episodes of silt pollution.

Earlier this year, Pennsylvania American Water’s renovation of the old dam at the No. 7 Reservoir in Dunmore inadvertently released large amounts of silt and sediment into the lower 4.8 miles of Roaring Brook, and beyond.

The state Department of Environmental Protection became aware of the silt pollution Feb. 4 and investigated. In March, the DEP determined the silt pollution in Roaring Brook violated state law and regulations. Later that month, the agency released a study that determined the excessive silt has significantly impaired Roaring Brook, nearly wiping out macroinvertebrates by 90-95% in some areas by burying stream-bottom habitats in sandy silt up to 3.5 feet deep.

Roaring Brook’s flow appears to have washed silt from the dam out of the main stream channels, said Bernie McGurl of the Lackawanna River Conservation Association.

“There’s a lot of sediment that got into the creek. Most of it in the stream (remaining) is on the embankments and in the shallower spots,” McGurl said. “There are a few spots where there’s a foot or two of sediment that’s finer and distinguishable from larger stones that are part of the natural sediment of the creek.”

The water company, with DEP oversight, devised an “action plan” in April that calls for building rock dams in four locations in Roaring Brook in the borough and city, to contain flows of silt and sediment that later would be dredged out via pumping.

One spot required manual removal of sediment, which has already started, while the rock dams and dredging will occur at different times, according to DEP and PAW.

The four locations include two each in Dunmore and Scranton.

In Dunmore:

• The area immediately downstream of the No. 7 Reservoir dam previously had containment measures taken after the silt release. This area will be maintained and enhanced.

• DeNaples junkyard area. An existing access point was used to remove sediment along the banks using manual labor, hand tools and buckets for about 600 feet. About 40 cubic yards of sediment has already been removed, PAW spokeswoman Susan Turcmanovich said. A rock dam also will be built about 2,400 feet downstream of the dam.

In Scranton:

• The Myrtle Street Bridge area. A rock dam will be built just upstream of the pool area where the stream makes a hard bend to the left. There is a visible sand bar at this location. Work in this area could start the soonest.

• Cedar and Mattes avenues: A site visit here on April 2 confirmed there is a significant amount of sediment captured behind the spillway just downstream of the bridge that carries Cedar Avenue over Roaring Brook. Dredging via pump would extend 300 to 500 feet upstream of the spillway and bridge.

Even before the dam discharge, severe storms have muddied Roaring Brook.

The city already has a project underway in Roaring Brook at the Cedar/Mattes location that’s scheduled to be completed by July. This work includes sand bar removal, masonry wall rehabilitation and the addition of riprap in an eroded bank. This work is done under a Federal Emergency Management Agency declaration from a 2018 storm, city Business Administrator Eileen Cipriani said.

Roaring Brook flows through a concrete flood-control channel in the area of Cedar and Mattes avenues, where sediment from storms regularly collects behind the spillway that acts like a large catch basin. This location has had sediment removed regularly, depending on storms, Scranton City Council President Gerald Smurl said. Heavy equipment vehicles can access the brook at this spot via a gate at the intersection of Mattes and Cedar avenues.

“That gets cleaned out regularly. That’s why that gate is there,” Smurl said.

The water company has been in contact with the city regarding coordination of each one’s projects at the Cedar/Mattes spot.

The state Department of Transportation also is planning a rehabilitation project on the Cedar Avenue bridge possibly to begin in 2024.

The DEP’s approval of the water company’s Plan of Action for Roaring Brook sediment removal also does not limit remediation efforts to the four primary locations chosen. The DEP encourages the water company “to continue to seek access to other areas to remove the bulk of the sediment” discharged from the dam project, according to an April 18 letter from the DEP to the water company.

Meanwhile, the DEP also has FEMA project expected soon to remove sediment and debris at the confluence of Roaring Brook and the Lackawanna River.

The Lackawanna flows into the Susquehanna Rivers, which is a major feeder of the Chesapeake Bay.

“Anecdotally, I believe it (the silt from the dam) is cleaned up in the flow channel where you normally have flow. And the flow in springtime is high and fast and that flow really scoured out the sediment because it’s finer and it’s just been broadcast throughout the Chesapeake by now,” McGurl said. “It’s widely dispersed and lot of it moved downstream” into the other waterways.