Silverwood Lake Algal Bloom at Danger Level

SACRAMENTO, Calif. – Today, the Department of Water Resources (DWR) urged people to avoid physical contact with the water at Silverwood Lake in San Bernardino County until further notice and avoid eating fish from the lake due to the presence of blue-green algae.

Boating is allowed, but swimming and other water-contact recreation and sporting activities are not considered safe under the danger advisory due to potential adverse health effects. The danger advisory is in effect for the entire lake.

Advisories are based on the potential health risks from algae. Exposure to toxic blue-green algae, also known as cyanobacteria, can cause eye irritation, allergic skin rash, mouth ulcers, vomiting, diarrhea, and cold- and flu-like symptoms. Pets can be especially susceptible because they tend to drink while in the water and lick their fur afterwards. Keep pets away from the water.

Bloom conditions can change rapidly, and wind and waves may move or concentrate the bloom into different regions of the reservoir. The algal bloom can accumulate into mats, and scum, form foam at the surface and along the shoreline, and range in color from blue, green, white, or brown.

State guidelines on cyanobacteria and harmful algal blooms recommend the following precautions be taken in waters impacted by blue-green algae:

Take care that pets and livestock do not drink the water, swim through algal blooms, scum, or mats, or lick their fur after going in the water. Rinse pets in clean water to remove algae from fur.
Avoid wading, swimming, or jet or water skiing in water containing algae blooms, scum, or mats.
Do not drink, cook, or wash dishes with untreated surface water from these areas under any circumstances. Common water purification techniques such as camping filters, tablets, and boiling do not remove toxins.
Do not eat mussels or other bivalves collected from these areas. Limit or avoid eating fish. If fish are consumed, remove the guts and liver and rinse filets in clean drinking water. No fish should be consumed under a danger advisory.
Get medical treatment immediately if you think that you, a family member, friend, pet, or livestock might have been poisoned by blue-green algae toxins. Be sure to alert medical professionals to the possible contact with blue-green algae. Also, make sure to contact the local county public health department.

For more information, visit:

California Department of Public Health
State Water Resources Control Board
CA Office of Environmental Health Hazard Assessment
US Environmental Protection Agency: CyanoHAB website
Centers for Disease Control and Prevention

Maggie Macias, Information Officer, Public Affairs, Department of Water Resources
(916) 653-8743 |

-Simone Graham, Editor High Desert Gazette

This aerial view looks west toward Silverwood Lake nestled in the San Bernardino National Forest, formed by the 249 foot high Cedar Springs Dam. The reservoir provides regulatory and emergency storage, and helps firm deliveries to users along the East Branch Aqueduct of the California State Water Project. It also provides recreation, and assures continuity of discharges through Devil Canyon Powerplant. Photo taken May 9, 2014.
Florence Low / California Department of Water Resources

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