Danger warning at Indian Creek Reservoir for harmful algae blooms

Submitted to the Tribune
A signs posted in July at Indian Creek Reservoir warns visitors of toxic algae.
Kurt Hildebrand/Record Courier

SOUTH LAKE TAHOE, Calif. – The Lahontan Regional Water Quality Control Board, in collaboration with Alpine County, is urging visitors to stay out of the water at Indian Creek Reservoir after recent tests confirmed the lake is being impacted by harmful algal blooms that are especially dangerous for children and dogs. 

The lake is posted with a recreational advisory of “Danger” to alert visitors of the elevated risk. Recreational water users are encouraged to follow the below guidance until further notice. 


  • Stay out of the water, including watercraft.
  • Do not let pets and other animals drink or go into the water, or go near the scum.
  • Stay away from scum, and cloudy or discolored water.
  • Do not eat fish or shellfish from this water.
  • Do not use this water for drinking or cooking. Boiling or filtering will not make the water safe.

South Tahoe Public Utility District, a regional partner that assists with sampling during the Labor Day pre-holiday assessment, observed a spilled paint appearance while sampling at Indian Creek Reservoir. Results confirmed toxins were present at danger level thresholds at all three locations sampled. More info can be found at My Water Quality: California Harmful Algal Blooms (HABs).

Cyanobacteria, a group of organisms that form harmful algal blooms, can produce potent toxins. HABs can cause skin inflammation, gastrointestinal distress, headaches, agitation and weakness, or abnormal breathing if HAB material is swallowed while swimming.

Dogs and children are most susceptible to exposure because of their smaller body sizes, increased potential to swallow water while swimming, and tendency to stay in the water longer. If you suspect exposure, wash your children and dog immediately. 

The bloom occurring in the lake appears suspended on the water’s surface. Due to the size and toxicity of the bloom with increasing temperatures and decreased precipitation this time of year, the bloom may proliferate and alter its potential to produce toxins. 

Bloom conditions can change rapidly, as the winds and waves move or concentrate the bloom into different regions of the lake. In some areas, the bloom may concentrate and form a film or scum on the water surface. The color of the water may also appear discolored as bright or dark green and brown. 

The District has posted advisory signs to notify recreational users of the bloom. The State Water Resources Control Board will provide regular updates to inform the community when postings are removed on the California HAB Reports Web Map.

The Water Boards recommend that people practice healthy water habits while enjoying the outdoors this summer at your local lake, river or stream: 

  • Heed all instructions on posted advisories if present 
  • Avoid algae and scum in the water and on the shore 
  • Keep an eye on children and pets 
  • If you think a harmful algal bloom or toxic algal mats are present, do not let pets and other animals go into or drink the water or eat scum/algal mats on the shore 
  • Don’t drink the water or use it for cooking 
  • Wash yourself, your family and your pets with clean water after water play 
  • If you catch fish, throw away guts and clean fillets with tap water or bottled water before cooking 
  • Avoid eating shellfish if you think a harmful algal bloom is present 

Get medical treatment immediately if you think that you, your pet, or livestock has gotten sick after going in the water. Be sure to alert the medical professional to the possible contact with cyanobacteria. Also, make sure to contact the local county public health department. 

To report a bloom, do one of the following:

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