From SDCK Watershed Wiki
Frequently Asked Questions (FAQs)
Under Development - Please send questions to firstname.lastname@example.org
Where are beach water quality samples collected? What are the samples tested for?
Samples are collected in ankle to knee deep water along the shoreline. Samples are analyzed for fecal indicator bacteria (FIB) which include fecal coliforms and enterococci. These bacteria are used to indicate the likelihood of the presence of pathogens (other bacteria, virus and protozoa). The levels of bacteria in any one sample should not be greater than the following state standards: Total coliform 10,000 per 100mL. Fecal coliform 400 per 100mL. Enterococci 104 per 100mL.
What’s going to happen if I go in polluted or contaminated water?
Maybe nothing, but there is an increased risk of illness. Developing an illness depends upon many factors, including the concentration of pathogens in contaminated water, the degree of exposure (how much water you ingest), age, your immune system status, other health issues, etc. Possible illnesses include respiratory and ear infections, gastroenteritis (vomiting and diahrrea, sometimes with fever), and skin infections.
How does water quality where are samples collected in knee deep water compare to the surfing line-up 50-200 yards offshore?
A 2004 study conducted by the Southern California Coastal Water Research Group (sccwrp.org) found that bacterial levels exceed standards more often in knee deep water than offshore water during dry weather, but less so during wet weather. So for dry weather, this means water quality offshore should be better than the shoreline. However, if you go surfing at a location under advisory, remember you still have to paddle out in the shallow water, and then there's wipeouts too at the end of a ride that are usually in shallower water. For wet weather (up to 3 days after rain), bacterial levels between shoreline and offshore will be similar.
How long after a rain event does urban runoff impact water quality?
Bacteria and other pollutant levels will increase significantly (often several magnitudes above dry weather levels) in ocean and bay waters after stormwater or other sources of water wash urban runoff through storm drains, rivers, and lagoon outlets. The increased levels can last a few hours to a few days depending upon the volume of runoff, concentration of pollutants, mixing, dispersion, and other factors. Water quality at most locations returns to background levels within 72 hours (3 days). If you are concerned about getting sick from ocean or bay water after it has rained, avoid water contact for the full 3 day period. If you feel like rolling the dice, see this table on likelihood of contamination for different county beaches following small (less than 0.5") rain stroms.
Will beaches be as contaminated later in the rainy season as after the first big storm?
Probably not, but its risky to assume not because urban runoff is generated year round, every day. (See our Pollution Prevention Tips).
If I wear earplugs, then shower immediately after and use mouthwash, can I safely surf at the Tijuana Slough following rain?
Unless you are wearing a full body condom, no. South county beaches are put under a closure when they may be impacted by sewage contaminated runoff from the Tijuana River. Sewage is known to contain human pathogens.
What if I've been immunized for Hepatitis A?
Then you have immunity for this one virus, but not the other 90 or so pathogens that can be found in sewage and possibly in stormwater runoff.
I've surfed at beach X for years, often when signs are posted, and I don't get sick. Do I have acquired immunity from surfing here for so long?
Unlikely. There are too many factors, including the variety of pathogens potentially found in contaminated water, the number of strains that can be associated with a single pathogen, and the likelihood that most pathogens in contaminated water are not concentrated enough in recreational waters to create immunity. Note: this likelihood of low concentration of pathogens does not guarantee safety from contact with contaminated water; this is why water contact advisories and closures are issued. (this answer provided by the County of San Diego, Public Health Services, Epidemiology and Immunization Services Unit)
Why don't I see the temporary signs posted on the beach after it rains?
There are not enough signs nor staff to post them. While many coastal outlets are posted with permanent metal warning signs, additional temporary signs are not posted for General Advisories.
The protocol after it rains is to issue the 3 day General Advisory for all beaches. How come this is not more specific to each beach?
There are two reasons: First, the variability of ocean currents, pollutant loads, and others factors make it impossible to say with certainty that any one beach is contaminated and another is not. Secondly, its also impossible to simultaneously collect 40 - 90 samples in one morning. And if you could, you would still have to wait at least 1 day to get the test results, so the information would not be timely. However, having said all that, there are distinct patterns of bacterial contamination for different beach types (nearby coastal outlet or none, open coast or enclosed bay). This table lists the beach types and likelihood of contamination following small (less than 0.5") rain stroms. This table is intended as a guide and does not guarantee safety from illness or replace the General Advisory message to avoid ocean and bay water contact for 72 hours following rain.
Who provided this information on this table?
Clay Clifton, who worked for nine years as the Ocean Recreational Water Program Coordinator for the County of San Diego, Department of Environmental Health.
What is the foamy water I see along the shoreline sometimes? It looks like some kind of pollution or contaminated water.
Seeing discolored foam along the shoreline is not uncommon, nor is it necessarily an indication of contaminated water. (In fact, contaminated water often has the same appearance as uncontaminated water, so don't rely upon appearance as an indication of quality.) The foam (which can be white to brownish in color), is usually produced by high winds that emulsify organic matter like kelp and plankton in ocean waters.
What is red tide really and is it a natural occurrence in San Diego? Why does it occur and is it harmful to humans or wildlife?
Red Tide is a common name for a phenomenon where blooms of certain algal species, which contain red-brown pigments, cause the water to appear to be colored red. Occasionally single celled plants that live in the ocean called phytoplankton can grow very fast and form very dense populations or "blooms". Some of the blooms can be harmful to their environment by depeting oxygen levels in water or by producing toxins. These are commonly referred to as Harmful Algal Blooms, ("HABs"). The two major groups of phytoplankton that have HAB species are diatoms and dinoflagellates.
Not all harmful algal blooms discolor the water and some HABs are formed by species of phytoplankton which can produce potent toxins that can be transferred through the food web where they affect zooplankton, shellfish, fish, birds, marine mammals, and humans that feed either directly or indirectly on them. This type of HAB does not necessarily require the same dense populations as the prior to show harmful effects. (this answer is copied from Southern California Coastal Ocean Observing System, www.sccoos.org)
What about sand? I've heard some beach sand has very high levels of bacteria.
Beach sands near storm drain outlets can have high levels of bacteria. Our suggestion is to not eat sand.
What should I do with trash that I find floating?
Put it in your wetsuit and then in a trash can when you are back on the beach.