Toxic Blue Green Algae in Idaho Lakes this Summer

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Toxic Blue Green Algae in Idaho Lakes this Summer

As summer is starting to fade into fall I am reminded and wishing for that amazing warm weather we saw this season. With that weather and current pollutants found in lakes, two documented blue green algae blooms exploded in Fernan and Hayden lakes causing health advisories and shutting down lake access.

Why is Blue Green Algae showing up in our lakes?

Blue Green Algae is actually a bacteria that photosynthesizes like algae. It is microscopic and causes lake to turn into green soup. When the bacteria rise to the surface of calm, static waters (like many of our lakes) it will form a scum that blocks light to other plants, shading them out and will dominate that body of water. These blooms are caused by warm weather in combination with inputs of phosphorus and nitrogen, which come from fertilizers, organic wastes, stormwater and septic systems. According to Panhandle Health District (PHD), “often excess nutrients associated with algae blooms are caused by pollution from human activities.” During the summer when irrigation is kicking in, runoff from farms and lawns carry fertilizers and nutrients with it into our waterways, creating conditions for an algae bloom. Because of blue green algae and the amount of phosphorus in the water a TMDL (total maximum daily load) for Fernan Lake is being issued by Idaho Department of Environmental Quality (IDEQ). Black Lake and Lake Cocolalla both have TMDLs for phosphorus due to past blue green algae blooms. Hauser Lake, Lake Spokane, Newman Lake have also had past blue green algae blooms.

Why is Blue Green Algae Toxic?

Blue Green Algae is toxic to humans and wildlife. Although it is unknown why some algae is toxic and some is not, we do know that particular strains are dangerous. These toxins when ingested can be lethal to humans and animals. Certain strains will cause skin irritation and allergic response, and when ingested can cause muscle spasms, labored breathing, liver damage, convulsions and death. The two different strains were found on Fernan and Hayden and both are toxic. When blue green algae is identified health advisories must be made to ensure public health. People are warned to stay away from the water and do not let pets or livestock drink or get in the water.

What can we do to prevent Blue Green Algae?

As the weather gets cooler blue green algae has and will disappear in the lakes. However, next summer if conditions are right we will see blue green algae again. In order to prevent these blooms, residents and landowners need to reduce their impact by decreasing the input of nutrients in the water. If you are going to use fertilizers, follow the instructions, do not over apply and do not over water causing run-off. It is also very important to maintain septic systems so they do not contribute to the problem. IDEQ is working on assisting residents with improving water quality and according to a press release from PHD, “the Hauser Lake Watershed Coalition adopted the Lake-A-Syst program this summer to provide lakeside landowners with information and tools to reduce nutrient inputs from their properties.”


By | 2012-09-06T13:51:01+00:00 September 6th, 2012|blog, Community, Hayden Lake, KEA, Water, Wildlife|1 Comment

One Comment

  1. David Dolan May 7, 2015 at 9:43 am - Reply

    We have reports from some local experts that algae has appeared in Spirit Lake, which I live on. I have noticed an odor in my water and also have seen that the lake water is murky with brown patches on the top of the lake. We need to be informed by someone in authority if the water is indeed becoming dangerous to us as soon as possible. Thank you for any information you might be able to provide.

    David Dolan
    7330 West Lake Drive
    Spirit Lake Id 83869


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