Pacifica extends water‑quality monitoring as scientists report widespread bacteria in San Pedro Creek and at Linda Mar

The Pacifica City Council voted unanimously Aug. 26 to extend the city’s agreement with the San Mateo County Resource Conservation District (RCD) for ongoing water‑quality monitoring of San Pedro Creek and Linda Mar (Lindamar) Beach.

The council approved the fifth amendment to the interagency agreement — continuing RCD sampling and microbial source‑tracking work through 2026–2028 — as part of its consent calendar. The monitoring feeds the San Pedro Creek and Pacifica State Beach Total Maximum Daily Load (TMDL) work required under Clean Water Act section 303(d), city and county staff said.

The extension comes after a staff and partner presentation that summarized multi‑year sampling and genetic source‑tracking results. RCD water quality specialist Clifton Herman said the program uses two main tools — bacteria concentration measurement and microbial source tracking (MST) — to determine whether bacteria in the creek are associated with humans, dogs or horses and where in the watershed they appear. “We did see high concentrations at that 1 location,” Herman said, pointing to a storm drain at Seville and Oviedo Court (the site labeled “COSD” in RCD figures) as a recurring hotspot of human‑associated markers.

Why it matters: elevated bacteria are an indicator of possible pathogens that can make people sick, so the monitoring helps target where remediation or outreach can reduce public‑health risk. The RCD and the Lindamar Water Quality Coalition presented complementary datasets and recommended more targeted remediation and grant applications to address controllable sources.

What scientists presented

Kellix Nelson, executive director of the San Mateo County RCD, told the council the district has worked with Pacifica since 2016 under an interagency agreement to fulfill TMDL monitoring obligations and to complete the Pacifica State Beach Bacteria Special Study. Nelson described the RCD as a locally led, non‑regulatory conservation district that provides technical assistance across public and private land.

Clifton Herman (RCD) summarized 2024 monitoring. RCD sampled multiple fixed sites in the San Pedro Creek watershed four times in the wet season and four times in the dry season, then averaged results within each season. The wet‑season maps showed more widespread exceedances; in the dry season monitoring the COSD storm drain site repeatedly showed high concentrations localized to that subwatershed, Herman said. MST testing, which looks for genetic markers tied to specific species, showed detections of human‑ and dog‑associated markers in different parts of the watershed. Herman noted that MST indicates presence but is not strictly quantitative: “Microbial source tracking tells us what is there, but it does not tell us how much.”

John Keener, scientific lead for the Lindamar Water Quality Coalition, presented more than a year of weekly (Monday) samples at four creek sites and showed that enterococcus and E. coli counts were frequently above state recreational thresholds. Keener said about 83% of their enterococcus samples exceeded the recreational standard and that the largest spikes came during and immediately after rain events; he added that occasional very high dry‑season readings remain unexplained. “Well, Lindamar Beach is polluted,” Keener told the council, and he urged caution for beachgoers near the creek mouth.

City actions and staff comments

Deputy Director of Public Works (Wastewater) Louis Sun briefed the council on public‑works efforts in the Linda Mar watershed, including a lateral grant program, extensive CCTV inspection of sewer lines, the Lower Linda Mar Sewer Rehabilitation Program (on track for fall completion), and continued maintenance of the city’s equalization basin that reduces sanitary sewer overflow risk during wet weather. Sun also highlighted the city’s pet‑waste reduction outreach and on‑the‑ground work to stock dog‑waste stations.

Council action: Council approved the fifth amendment to the city’s monitoring agreement with the RCD as part of the consent calendar (motion by Council Member Beier; second by Council Member Wright). The consent calendar was adopted unanimously.

Public comment and partner commitments

Several community members and volunteer groups spoke in support of continued monitoring and remediation. Patrick James Kavanaugh, director of the Pacific Beach Coalition, urged council to not only extend monitoring but to “augment, catalyze, and sustain” community‑based solutions such as beach cleanups and habitat restoration.

Teen and student voices joined the public record: Geneva Chan, a Terra Nova High School student, offered student volunteer support for outreach and education.

Next steps and caveats

Presenters emphasized the complexity of interpreting bacteria counts. RCD staff and coalition volunteers asked the council to support targeted follow‑up work — focused sampling above and below suspected sources, additional quantitative PCR testing, and grants to implement green‑infrastructure or storm‑drain remediation in the Crispi Canal subwatershed near the COSD storm drain. Nelson said the RCD and city staff have applied for grants (including NOAA coastal resilience and other regional funding opportunities) to fund remediation projects.

Council members asked for regular updates on the monitoring results and on city efforts to replace leaking laterals and other infrastructure. Staff said city lateral replacement counts and additional flow‑of‑funds detail would be provided in subsequent briefings.

For now, the monitoring program will continue under the extended RCD agreement through 2026–2028; staff and partners said that continued sampling and targeted follow‑up will guide future capital projects and grant applications aimed at reducing bacteria inputs to San Pedro Creek and protecting Linda Mar beachgoers.