Karuk’s Water Quality Program field crews were out at various locations from Orleans up to Iron Gate and the Salmon and Scott Rivers setting up harmful algal bloom monitoring equipment the week of July 13th, 2026. During this work, potentially toxic algal mats were identified growing on the bottom of the Klamath, Salmon, and Scott Rivers, as well as Dillon Creek. Water Quality Program staff will be out every two weeks throughout the summer monitoring and sampling the algae in coordination with California’s Northcoast Regional Water Quality Control Board.
While some harmful algal blooms are caused by algae or cyanobacteria that grow floating in the water, some algae or cyanobacteria grow attached to the bottom surface of waterways (benthic) and can form algal mats. If you see algal mats the recommendation is for children, dogs, and adults to not touch or inadvertently ingest any algal mat material in the water or found stranded on the river banks. In addition, dogs should not drink water directly from the rivers. If your dog is exposed, please wash them immediately. These recommendations are based on the potential health risks posed by the toxins that can be produced by algal organisms, commonly cyanobacteria, that can form algal mats. The potentially toxic algal mats can be found either attached to the bottom, floating in the water, or stranded on the river bank. The appearance of algal mats ranges from bright to dull-green, orange, brown, and maroon material. In summary, when in doubt avoid touching algal mats.
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 or incidentally ingesting the mat material. Be sure to alert the medical professional to the possible contact with cyanobacteria. Also, make sure to contact the local county public health department.
Source: https://mywaterquality.ca.gov/habs
