Algae Update for Discovery Bay
Contra Costa Environmental Health (CCEH) encourages anyone planning to boat or enjoy the water in or around the Sacramento-San Joaquin River Delta this weekend to stay safe and avoid harmful algae blooms (HAB).
A bloom is a buildup of blue-green algae (cyanobacteria) that creates a green, blue-green, white or brown coloring on the surface of slow-moving waterways. Contact can make people or pets very sick.
The East Bay Regional Park District has posted a “danger” advisory at Big Break Regional Shoreline in Oakley at the kayak launch and around the fishing dock after detecting cyanobacteria in the water.
A “danger” advisory means:
Stay out of the water, and do not touch algae scum in the water or on the shore
Do not use the water for drinking, cleaning or cooking
Do not let pets or livestock enter or drink the water
Do not eat fish or shellfish from the water
Additionally, the California State Water Resources Control Board has posted a “caution” advisory around the mouth of Mormon Slough near the Morelli Boat Ramp due to the presence of cyanobacteria.
Visitors should follow the directions on all posted signs and: Do not swim or wade near algae or algae scum, Keep children and pets away from algae in the water or on the shore, Do not drink the water or use it for cooking or cleaning, Don’t eat shellfish from the water
Visit cchealth.org/eh/hab for health and safety instructions associated with HAB advisories.
The California State Water Resources Control Board also found small amounts of cyanobacteria in water sampled in three other areas: Fourteenmile Slough/White Slough, Buckley Cove and the San Joaquin River at Windmill Beach. Other waterways may also have cyanobacteria, but they’ve not been reported.
Whether or not there’s a posted advisory, protect yourself and your pets by rinsing off with fresh water after touching the water, and make sure dogs don’t drink the water or swim near algae blooms. Bring fresh drinking water for your pets.
If you see large algae blooms in the water, do not swim and avoid contact.
The Central Valley Regional Water Quality Control Board, had staff in Discovery Bay on May 02, 2019 collecting water samples for a nutrient loading assessment study they are conducting. During the sampling, staff noted small clumps of visible cyanobacteria at three of the sampling locations.
These locations were the Yacht Harbor near the BoardWalk Grill, Pebble Bay along the deep channel and at the mouth of Discovery Bay and Indian Slough.
A water sample was collected at the Yacht Harbor for cell identification under the microscope. The cyanobacteria identified included Aphanizomenon sp., which was the dominant cyanobacteria within the sample, Dolichospermum sp. and Pseudanabaena sp. No Microcystis sp. were observed in the samples.
The amount of cyanobacteria observed in these areas was low and no toxin testing has been done.
Discovery Bay are cautioned to be aware that cyanobacteria are starting to appear in the area and to exercise care when recreating in the water. The California Water Quality Monitoring Council’s Harmful Algal Bloom (HAB) Portal provides information on healthy water habits that all water users should follow to protect themselves from a potential HAB. Additional information on algae blooms can be found here: https://cchealth.org/eh/hab/
You can also find the press release dated August 29, 2019 posted on the Contra Costa Environmental Health Harmful Algal Bloom (HAB) webpage below:
Field Photos:Taken at the Yacht Club on May 02, 2019 during mid-morning. (~10:00 am). Water appeared green in color and cyanobacteria were observed suspended in the water column and at the surface.