SANTA ROSA (CBS SF/BCN) — Water quality regulators let a Sonoma County-based quarry know last week it could face a $4.5 million-fine for multiple alleged violations of the Clean Water Act that threaten the survival of endangered salmon populations in tributaries of the Russian River.

The proposed fine from the North Coast Regional Water Quality Control Board is part of a legal proceeding known as an administrative civil liability that alleges the operator of Mark West Quarry, Dean Soiland, doing business as BoDean Co. Inc., discharged highly turbid stormwater from its quarry operations into Porter Creek from September 2018 through May 2019.

READ MORE: Afghan American Family Finally Returns to California; 'It's A Story Of Hope'

The complaint alleges that BoDean violated requirements of its National Pollutant Discharge Elimination System general permit by failing to implement best management practices that would have reduced or prevented sediment in stormwater discharges.

The complaint also alleges that from December 2018 through May 2019, the quarry discharged more than 10.5 million gallons of highly turbid stormwater, causing significant amounts of fine sediment to deposit in Porter Creek.

READ MORE: Will The Oakland A's Strikeout With Fans Over Proposed 2021 Ticket Price Hikes?

“Stormwater runoff from quarries and other industrial operations exposed to rainfall can cause substantial impacts to water quality unless practices are in place and maintained to prevent soil erosion and sediment transport,” said Claudia Villacorta, North Coast Water Board assistant executive officer.

“Had the quarry operator complied with the storm water permit, impacts to water quality could have been avoided. The proposed fine reflects the extent of those impacts and the operator’s failure to implement minimum practices established in the permit,” Villacorta said.

A public hearing to consider the complaint and vote on whether to approve the $4.5 million fine is scheduled for Dec. 2-3 before the North Coast Water Board.

MORE NEWS: Santa Rosa Seeks Input From Public on Vacation Rental Ordinance

© Copyright 2021 CBS Broadcasting Inc. and Bay City News Service. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.