On May 10, the Environmental Protection Agency (EPA) quietly signed off on a plan meant to reduce pollution in the 146-square-mile Petaluma River Watershed.
That’s right. Although the problem is rarely discussed, the Petaluma River has been listed as “impaired” by excessive levels of bacteria since 1975.
The bureaucratic document approved by the EPA is known as a Total Maximum Daily Load (TMDL). It sets levels of acceptable waste discharge from various sources in an attempt to lower the levels of fecal bacteria found in the watershed until the water is deemed clean.
While preparing the TMDL, scientists from the San Francisco Bay Regional Water Quality Control Board tested water from throughout the watershed for Fecal Indicator Bacteria to determine the amount of waste from warm-blooded mammals that has seeped into the water. Although indicator bacteria themselves are not dangerous, scientists use the strains to detect potentially dangerous levels of contamination in the water.
In a report accompanying the TMDL, water board staff identified 12 sources of pollution, which they then lumped into three general categories: human waste, animal waste and municipal stormwater runoff. In tests conducted between 2015 and 2016, water board scientists found bacteria tied to humans, horses, cows and dogs throughout the Petaluma River and its tributaries.
When asked in late 2019 about the levels of E. coli discovered in the Petaluma River, Farhad Ghodrati, an environmental scientist with the San Francisco Bay board, said the test results showed “some of the highest concentrations we have seen in the region.”
At the same time, Dr. Celeste Philips, who then served as Sonoma County’s Health Officer, warned Petaluma River users against drinking the river water or using the water for cooking due to the levels of E. coli. “Adults and children should wash hands/shower and towel dry after swimming; rinse off pets after they come into contact with the water,” Philips added.
Although some of the various parties named in the report appear to be undertaking the work required of them by the TMDL, the clean-up process will likely stretch on for at least a decade, according to an implementation timeline.
However, if critics of the plan are correct, the process may stretch on much longer due to flaws in the TMDL. San Francisco Bay Keeper, a nonprofit focused on cleaning up Bay Area water sources, raised concerns throughout the approval process that the plan does not meet the legal requirements of a TMDL laid out in the Clean Water Act.
“Baykeeper has concerns about the strength and legality of the Petaluma River Bacteria and Nutrients TMDL because we believe the TMDL isn’t specific enough or strong enough to lead to meaningful improvements for the river,” Ben Eichenberg, a staff attorney with Bay Keeper, said in a statement. Among other weaknesses, Eichenberg says that the current TMDL fails to identify specific pollutant sources and “underestimates the scope and cost of what it will take to clean things up.”
The regional and State Water Quality Control Boards largely dismissed Bay Keepers’ concerns throughout the plan approval process, and the EPA appears to have signed off without making any changes.
Whether or not the current plan is strong or specific enough, the current TMDL and accompanying documents do offer some insight into the reason the watershed is polluted—and what should be done about it. Now, without further delay, let’s take a look at a few of the sources and suggested solutions.
Cattle and Horses
According to a 2020 staff report, the 17 cow dairies in the Petaluma River Watershed are home to an estimated 11,000 cows. Meanwhile, 32 horse farms house approximately 8,600 animals in the watershed.
Given the number of four-legged watershed residents, it shouldn’t come as a surprise that tests found that bacteria originating from cow and horse waste “were identified at very high rates throughout the watershed, in both dry and wet seasons.”
In order to comply with the TMDL, Confined Animal Facilities, the technical term for high-density commercial ag operations, must prove they comply with Water Board regulations “as soon as possible,” and monitor water quality as required by the Water Board moving forward.
Meanwhile, grazing operations in the watershed, which include less dense ag operations, must obtain a Grazing Order from the Water Board by September and follow Water Board regulations.
Sewer Systems
Sewer system overflows during heavy rainstorms appear to be another historically significant source of pollution in the watershed.
Between 2007 and 2017, the Petaluma and the Penngrove Sanitation Zone, a small district located north of Petaluma, reported 94 large overflows, spewing a total of 1.35 million gallons of sewage into the watershed.
Tests in 2016 and 2017 “detected fecal bacteria of human origin at many sites throughout the watershed, which could point to discharges from the sanitary sewer collection systems as a likely source,” the 2020 staff report notes.
The report tasks Petaluma and the Penngrove Sanitation Zone with preparing an updated Sewer System Management Plan identifying necessary repairs to the systems within a year. Once the plans are approved by the water board, the agencies will have 10 years to complete all of the required improvements. More pressing projects identified in the report must be completed within five years.
Homeless Encampments and Marinas
People living in informal shelters inside the watershed may also pose a risk to water quality.
In July 2017, there were an estimated 17 encampments along waterways within Petaluma city limits. If encampment residents are not disposing of their waste properly, it could make its way into the waterways.
As a result, the TMDL requires Petaluma and CalTrans, the state transportation agency, to create a plan to “prevent human waste discharges into storm sewer systems from homeless encampments on City of Petaluma and Caltrans properties within the Petaluma River watershed” by next May. The resulting plan must be implemented by the end of 2022.
The TMDL also requires marina owners and operators to increase “no dumping” education for boat owners by the end of 2021, and to create a plan review and install proper waste management equipment by next May. The marina owners must complete the improvements within five years.
More information about the Petaluma River Bacteria TMDL is available here.
