Monitoring beach water keeps people and animals safe

Before heading out to your favorite swimming hole this summer you may want to check in on King County’s Swim Beach Monitoring Program to see if there is any bacteria or algal lurking in the water that could make you sick.

“There may be multiple bacterial sources for high fecal coliform counts,” states Debra Bouchard, senior limnologist and water quality planner with King County Water and Land Resources Division. “Potential sewage spills are the highest concern because of the increased risk of transferring disease from a human source.”

Algal Bloom

Pond scum at Lake Ketchum.

Other risks include fecal contamination from waterfowl, dogs and cats, surface run-off from poorly drained grassy areas adjacent to the beach, high concentrations from nearby creeks, and poor water circulation in the swimming area may contribute to high bacterial counts. Algal blooms are also a hazard that swimmers need to be aware of before entering the water, as some algal species can present potential health risks to people and animals when in bloom.

“Some beaches are more prone to toxic algae blooms due to high nutrients, wind conditions, shallow water, and poor circulation,” said Bouchard. “Algae and bacteria tend to accumulate in protected coves that are less flushed out by water movement.”

Residents can help prevent bacteria from growing in local swim beaches by not taking dogs to public swimming beaches (there is a fine for having dogs on public beaches in Seattle), properly disposing of pet waste, ensuring children are taken to restroom facilities often, and not feeding geese or ducks in local parks.

“If geese spend less time at the parks, there will be fewer feces and the bacterial load will decrease,” said Bouchard. “Park personnel and the King County Marine Patrol have replaced the practice of washing duck and geese feces off of the walkways and into the swimming area.”

Most swimming beaches have their water quality tested weekly by environmental specialists from the King County Department of Natural Resources and Parks from mid-May to mid-September. The beach monitoring program monitors 27 freshwater beaches, 19 funded by King County and eight funded by the cities of Shoreline, Mercer Island, Sammamish, Kenmore, and Maple Valley via interagency agreements.

While funding restrictions limit the number of beaches that King County’s monitoring program can monitor routinely for bacteria and algal toxin, the state has a Toxic Algae Program that allow anyone to send in a sample for algal toxin testing.