Cyanobacteria (blue-green algae) advisory issued for Twin Valley Reservoir

June 23, 2023

CLARESHOLM – Cyanobacteria (blue-green algae) has been identified in the waters of Twin Valley Reservoir. Residents living near the shores of this reservoir, as well as visitors to this reservoir, are advised to take the following precautions:

As always, visitors and residents are reminded to never drink or cook with untreated water directly from any recreational body of water, including Twin Valley Reservoir, at any time. Boiling of this water will not remove the toxins produced by cyanobacteria. An alternate source of drinking water should also be provided for pets and livestock, while this advisory is active.

Cyanobacteria is naturally occurring, and often becomes visible when weather conditions are calm. Appearing like scum, grass clippings, fuzz, or globs on the surface of water, cyanobacteria (blue-green algae) can be blue-green, greenish-brown, brown, and/or pinkish-red, and often smell musty or grassy.

People who come in contact with visible cyanobacteria or who ingest water containing cyanobacteria may experience skin irritation, rash, sore throat, sore red eyes, swollen lips, fever, nausea and vomiting and/or diarrhea. Symptoms usually appear within one to three hours and resolve in one to two days. Symptoms in children are often more pronounced; however, all humans are at risk of these symptoms. Exposure to the bacteria may be fatal to pets.

Weather and wind conditions can cause algae blooms to move from one location in the reservoir to another. As such, this advisory will remain in effect for Twin Valley Reservoir, until further notice.

Please note that waters of Twin Valley Reservoir in which the cyanobacteria bloom is NOT visible can still be used for recreational purposes, even while this Health Advisory is in place.

If you suspect a problem related to cyanobacteria or if you require further information on health concerns and cyanobacteria, please call Health Link at 811. Additional information is also available online, at www.ahs.ca/bga.

Alberta Health Services is the provincial health authority responsible for planning and delivering health supports and services for more than four million adults and children living in Alberta. Our mission is to provide a patient-focused, quality health system that is accessible and sustainable for all Albertans. Our current focus is on reducing emergency department wait-times, improving EMS response times, increasing access to surgeries, and improving patient flow.