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By Emily Rasmussen

High bacteria levels in samplings from Rancho Mission Viejo Riding Park overland flows near San Juan Creek during wet weather exceeds regulation standards, in one sample by almost 7,000 percent, which is closer to the levels of untreated raw sewage, new data reveals.

Amidst a lawsuit filed by Orange County Coastkeeper that claims the Rancho Mission Viejo Riding Park contributes to pollution in San Juan Creek, against the city of San Juan Capistrano, which owns the Riding Park’s land, and Blenheim Facility Management (BFM), which operates the Riding Park’s facilities—new data has shown high bacteria levels in a Rancho Mission Viejo Riding Park water sample during wet weather. The data, collected and analyzed by Sierra Analytical Laboratories—a state certified lab in Laguna Hills—shows an exceedance of fecal coliform and enterococci levels from the San Diego Water Board’s targets for wet weather.

A portion of San Juan Creek is marked as an Environmentally Sensitive Area, just across from the Rancho Mission Viejo Riding Park. Photo: Emily Rasmussen
A portion of San Juan Creek is marked as an Environmentally Sensitive Area, just across from the Rancho Mission Viejo Riding Park. Photo: Emily Rasmussen

“These are the highest numbers I’ve ever seen that aren’t from a composting or trash facility,” Orange County Coastkeeper Senior Staff Attorney Colin Kelly said.

The San Diego Water Board Basin Plan, which bases its bacterial targets by Environmental Protection Agency (EPA) guidelines, holds San Juan Creek to a wet weather numeric target for enterococcus of 104 Most Probable Number (MPN) per 100 milliliters, with a 22 percent allowable exceedance frequency.

In data collected from overland flows from Rancho Mission Viejo Riding Park by Sierra Analytical on Jan. 9, one sampling shows enterococcus levels of 700,000 Colony-Forming Units (CFU) per 100 milliliters. Enterococci are bacteria found in human and animal feces and can cause human and animal infections, according to the American Society for Microbiology.

“It definitely indicates some pollution in the water, that is why there are high numbers,” San Diego Water Board Water Resource Engineer Helen Yu said. “They are also close to the untreated sewage level, the lower level of untreated sewage.”

Roger Mitchell, engineering geologist at the San Diego Water Board who oversees the San Juan Capistrano region, said that although the city is tasked with monitoring discharges with San Juan Creek, the board has been monitoring it as well.

“The water board is aware of ongoing litigation between the city (of San Juan Capistrano) and Orange County Coastkeeper,” Mitchell said. “As far as the Water Board’s involvement, we’ve been out to the site, performed some inspections and found there were some deficiencies in terms of compliance with federal and state laws. Beyond that, the Water Board has not been closely involved with the litigation, we’re aware of it but we’re not a party to it.”

Source: Sierra Analytical Laboratories, San Diego Water Board Basin Plan, 2016

At the San Juan Creek Ocean Interface, where San Juan Creek meets Doheny Beach, Heal the Bay’s Beach Report Card gives an ‘F’ grade for wet weather and a ‘D’ grade for dry weather. The grades are based on a 30-day period ending on April 3, according to the Beach Report Card website.

“Even if there are lower numbers, such as 15,000 or 20,000 CFU, that is way above the allowable numbers (of 104 MPN),” Yu said, adding that CFU and MPN are interchangeable methods of measurement.

Yu said that these numbers “raise concern,” however, normally when samplings are collected during a rain event, there is a high concentration of bacteria as a sort of “first flash” on the surface. Then, they flush out and you’ll see lower concentrations, she said.

In the Jan. 9 data, four other samplings are recorded with lower levels of enterococcus. They range from 11,000 to 22,000 CFU per 100 milliliters.

“It’s a snapshot and doesn’t necessarily mean it’s a long term issue,” said Michelle Santillan, a water resource control engineer at the San Diego Water Board.

However, these numbers raise the possibility of people getting sick, Yu said.

“Bacteria themselves, especially enterococcus, they themselves don’t make people sick,” Yu said. “It is the pathogens associated with them in sewage that makes them sick.”

Sometimes, Yu added, concentrations can come from wildlife, such as seagulls. However, the 22 percent exceedance for the Basin Plan Wet Weather Numeric Targets would typically allow for variables such as wildlife, she said.

Creek (4)
The Rancho Mission Viejo Riding Park sits along the San Juan Creek. Photo: Emily Rasmussen

One of Orange County Coastkeeper’s claims in the lawsuit is that during wet weather, runoff of horse feces drains to San Juan Creek from the Riding Park. One of the main concerns, Kelly said, is that there are wash racks for the horses that directly drain into the Creek.

“I would like to check if there’s any onsite treatment facilities, if there are I would suppose they are doing a better job than to send this high concentration to the beach,” Yu said. “If they’re not, they should do a better job in installing, maintaining and operating the onsite treatment facility.”

The Rancho Mission Viejo Riding Park at San Juan Capistrano enrolled in a water quality permit issued by the State Water Resources Control Board. The permit requires water quality sampling from overland flows produced as a result of rainfall, San Juan Capistrano Assistant City Manager Jacob Green said.

“The sample results help to inform the facility operator (BFM) as to which areas of the property may need adjustment,” Green said. “The state’s permit allows for the facility to operate in an iterative manner (to adjust, modify and adapt the necessary water quality controls).”

Green said monitoring is necessary to make modifications and achieve compliance.

“A single set of results above the action levels does not mean the property is out of compliance or not complying with the permit, it simply communicates to the facility operator that adjustments should be made,” Green said.

Data collected from Feb. 27 also shows enterococcus numbers higher than the 104 MPN standard, with three samples ranging from 900 to 24,000 CFU.

Rancho Mission Viejo Riding Park is a 40-acre facility that is home to many equestrian events. Orange County Coastkeeper filed the lawsuit, which alleges Clean Water Act violations, against the city and BFM on June 2, 2017.

Green did not comment on the lawsuit; and BFM did not respond for comment by deadline.

EDITOR’S NOTE: This story was updated for clarification that data samples were collected from overland flows during wet weather from Rancho Mission Viejo Riding Park, not directly from San Juan Creek. 

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comments (1)

  • Steve Behmerwohld Reply

    I’m hoping that there will be another piece soon that shows the whole story. Roger Butow at Clean Water Now would be a good place to start.

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