Archives: Current Issues 2005

San Dieguito Lagoon Bacteriological Surveys (3/27/05)

Over a period of two years, from July 2001 to August 2004 Coastal Environments conducted bacteriological Surveys in the San Dieguito Lagoon for Southern California Edison. These surveys document that the river and the lagoon are impacted by current land uses. (Location map and photos are located below on this page)

The following comments are excerpts from the reports of Coastal Environments:

Water samples were collected at 7 sample stations identified on the map.
Samples were analyzed for bacteria (coliform., fecal coliforms and Enterococus) following Environmental Protection Agency approved methodologies. These bacteria are indicators of contamination.

Coliform bacteria live in the intestines of humans and others animals.
Fecal bacteria are a specific subgroup that live in the intestines of warmblooded animals. Some strains of fecal coliform can cause serious illness,but in general, coliform bacteria are harmless.

Specific pathogenic bacteria are more difficult to measure. They are generally the result of contamination by fecal material. The presence of the more readily-measured coliform bacteria is an indicator of fecal contamination, and thus can be used as an indicator of the likely presence of pathogens. When fecal coliforms are found in high densities in a water sample, it is probable that other fecal but pathogenic bacteria are also present.

Enterococcus is another type of fecal bacteria found in the intestines of warm-blooded animals, and some species can cause infection and illness. Studies by the EPA indicate that Enterococcus values have a greater correlation with gastrointestinal illness associated with swimming than coliform bacteria.

Station HS at the 22d DAA Horsepark property exceeded standards for 9 samples during this time period, while eight samples at station TR33 exceeded standards. Sixteen samples for total coliforms exceeded standards, compared to 8 for Enterococcus and only 2 for fecal coloforms. The ocean samples exceeded standards only once.

Water samples taken on February 24 2004 during a big storm event measured that all bacterial levels for the seven stations were above Health and Safety standards. Photographs were taken at the same time showing a large storage area of manure at the SW corner of the Horse Park property. Friends of the San Dieguito River Valley sent a letter of complaint to the Water Quality Control Board documenting with the photographs the leakage of polluted water to the Lagoon during the storm event. Fairgrounds personnel removed the manure from that location and after a few weeks the bacteria levels fell.

What these sampling surveys show is that there is a need for monitoring the water quality of both the river and the lagoon to determine the water safety of the lagoon for beach users and of the river for the wild life living in the park.

(Excerpted from the Coastal Environments report by Jacqueline Winterer)

map of sample locations

Letter to Water Quality Control Board 2004