Why are Kansas lakes turning green?

by: Matthew Self

Posted: Jun 2, 2023 / 05:06 PM CDT

Updated: Jun 7, 2023 / 07:46 AM CDT

TOPEKA (KSNT) – With the start of summer, some lakes around the state are beginning to look a little greener than usual.

If you’ve noticed that your local lake or reservoir isn't looking quite right, that could be because of the presence of blue-green algae. Every year, this algae appears in lakes across Kansas as a nuisance or, in some cases, a public health hazard. The presence of the algae can lead to the appearance of a dangerous harmful algal bloom (HAB).

The Kansas Department of Health and Environment (KDHE) say on their website that a HAB can appear like foam, scum or paint floating on the water. It can be a variety of colors like blue, bright green, brown or red. A bloom is hazardous to both people and animals, as it produces toxins that can be absorbed by ingestion, inhalation and skin contact.

Exposure to a HAB can include a rash, vomiting, diarrhea, fever, sore throat and a headache, according to the KDHE. People and animals that come into contact with an HAB are recommended to rinse the impacted area clean with fresh water. HAB-related incidents can be reported online by clicking here.

The algae comes from a "perfect storm" of conditions, according to KDHE Director of the Bureau of Water Tom Styles. A combination of plentiful nutrients, calm conditions and warm temperatures create an environment where the algae and HABs can form. The presence of some invasive species, like the notorious zebra mussel, can also cause HABs to appear.

Lakes in Kansas can be designated by one of three different levels if blue-green algae or a HAB are found in their waters by KDHE staff: Watch, Warning and Hazard. The KDHE recommends different precautions to those who might come into contact with lakes afflicted by the algae:

The KDHE regularly samples waterbodies for the presence of algae or HABs. Lakes and reservoirs can reach an elevated status, fall to a lower status or have their blue-green algae advisory lifted. For a list of all impacted waterbodies, click here.

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