A plan to set new restrictions on the levels of bacteria in the Petaluma River Watershed is nearing the next stage of approval.
At a virtual meeting on Tuesday, the California State Water Resources Control Board, an oversight body which presides over nine regional water quality boards across the state, will consider a plan meant to cap and reduce the amount of bacteria getting into the Petaluma River Watershed.
The federal Clean Water Act requires the state to create the regulatory plan, known as a Total Maximum Daily Load (TMDL), for water bodies which have been found to have excessive levels of pollution—in the case of the Petaluma River Watershed, the culprit is an excessive level of bacteria.
The hearing comes six months after the San Francisco Bay Regional Water Control Board approved the plan. The plan will be sent to the Environmental Protection Agency (EPA) for final approval If the State Water Board signs off on Tuesday.
The main stem of the Petaluma River has been listed as impaired—a regulatory term which means regulators have discovered unsafe levels of bacterial or other contaminants in the water—for over four decades.
Other parts of the watershed appear to have been contaminated more recently. For instance, the San Antonio Creek, which runs into Marin County, was added to the state’s list of impaired waterways as a result of recent data collected by the regional water board.
In November, Farhad Ghodrati, an environmental scientist with the San Francisco Bay board, told the Pacific Sun that water quality tests completed in recent years showed that the watershed has “some of the highest concentrations [of E.Coli indicators] we have seen in the [Bay Area] region.”
Excessive levels of bacteria in the watershed may be tied to a wide range of sources, including a wastewater treatment plant, sanitary sewer collection systems, private sewer laterals, onsite wastewater treatment systems (OWTS), vessel marinas, homeless encampments, confined animals facilities (e.g., cow dairies, commercial horse facilities), grazing lands (e.g., cattle and sheep ranches), domestic pet waste, and [stormwater runoff from municipal and Caltrans properties], according to a State Water Board staff report.
More information about the Petaluma River Bacteria TMDL is available here.
Click here to read our past coverage of the plan.