Harmful algal bloom at Indian Creek Reservoir prompts warnings

MARKLEEVILLE, Calif. - Elevated levels of blue-green algae in the Indian Creek Reservoir have prompted officials to warn users to stay away from algae and scum in the water and both humans and pets should avoid drinking it.

Routine sampling at the reservoir on July 22 found levels of cyanotoxin, Microcystins at 4.39. µg/L (microgram per liter), which is above the 0.8 µg/L level established for safety and triggers notification of the public.

South Tahoe Public Utility District manages the property and has posted caution signs at the reservoir

The Alpine Watershed Group (AWG) in coordination with the Lahontan Regional Water Quality Control Board has initiated a new Harmful Algal Bloom (HAB) monitoring program to more closely track the water quality in some of Alpine County’s most popular summer recreation reservoirs. AWG began these monitoring efforts in late June and plans to continue through mid October at Red Lake, Indian Creek, and Wet Meadow reservoirs at least once each month.

Fishing is still allowed at Indian Creek Reservoir but anglers should clean fish fillets with tap water before cooking and throw away the fish guts.

Cyanobacteria & Harmful Algal Blooms
Cyanobacteria, also known as blue-green algae, are naturally present in waterbodies and are an integral part of our ecosystems. When provided the right conditions, cyanobacteria can develop into a HAB from excessive growth. Blooms, if stimulated enough, can decrease water quality but are only considered an immediate threat to human and animal health if emitting toxins. Not all cyanobacteria produce harmful toxins, but in rare cases, toxin levels may be concentrated enough to cause rashes, diarrhea, or vomiting. If you see signs of a HAB, such as discolored, pea-green water, surface scum, floating algae, stay out of the water.

Warmer air and water temperatures, high nutrient levels, and slow and stagnant water can cause cyanobacteria to multiply at an excessive rate and turn in to a HAB. When HABs are present, the algal scum can be a variety of colors such as fluorescent blue, green white, red or brown. Blooms can have more than one color present and may look like thick paint floating on the water and give off a foul odor. HABs may move to different locations of the lake by wind or wave.

AWG will conduct HAB monitoring at Indian Creek Reservoir again on August 19. STPUD, who take a minimum of three cyanobacteria water samples per month, will be sampling at a higher frequency to monitor the status of bloom and will remove caution signs when levels of cyanotoxin are below the action trigger.