Hyalite Reservoir–State and local agencies continue to provide education and study Harmful Algal Blooms
By Moosetrack Megan

Posted: August 1, 2020

As Montanans and visitors head to local ponds, lakes and reservoirs for late summer fun, public health officials urge citizens to know the health risks of Harmful Agal Blooms, or “HABs”.

HABs are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs. Not all varieties of blue-green algae are harmful, but some can produce dangerous cyanotoxins. Blue-green algae blooms often look like pea soup, grass clippings or green latex paint. The algae are usually suspended in the water or appear as floating mats; they do not grow from the bottom like roots, mosses, or water plants.

An algal bloom with the potential to produce toxins harmful to human health has been identified at Hyalite Reservoir in the Custer Gallatin National Forest. The Gallatin City-County Health Department encourages recreationists to exercise caution to avoid an algal bloom that could potentially produce toxins that pose a risk to people, pets, and livestock. “We want people to be aware of risk from the algae,” said Lori Christenson, Environmental Health Director with the Gallatin-City County Health Department. “People should excerice caution where algal blooms are present.”

Importantly, “children and pets are more likely to ingest HAB infested waters because they spend most of their time wading in the shallow waters where algae can accumulate, and they have less control over how much water they ingest”, said Hannah Reidl, water quality specialst at the Montana Department of Enviromental Quality.

Hannah Riedl, continues, “ because we can’t track rapidly changing conditions in every body of water, we want people to be informed enough to make their own decisions. We also ask the public to help by reporting HABs so that we can respond quickly and hopefuly prevent people, pets and livestock from getting sick.”

Suspected HABs can be submitted, including photos, to the website: www.hab.mt.gov. This site also has a live map of reported HABs and identification information. When a HAB is reported to either DEQ or directly to the Gallatin City-County Health Department it is investigated to determine whether the bloom is nuisance green algae or potentially-toxic blue-green algae. In Gallatin County, the health department then works with the entities managing the waterbody to determine whether water quality testing results warrant safety advisories.

The City of Bozeman Water Treatment Plant personnel collect and test water samples weekly from multiple locations in Hyalite Reservoir for the presence of microcystin. This testing is done from July to October. The City of Bozeman treats water to remove contaminants at its treatment facility and is confident the city’s water supply has not been affected. Testing has confirmed that the city’s water is safe. The City of Bozeman monitors Mystic Lake for signs of HABs as well throughout the summer.

Suspect a HAB? “When in doubt, stay out. Do not drink, swallow, or swim in water that shows signs of a HAB and be sure to keep kids, pets, and livestock out too” said Lori Christenson, Environmental Health Director, for Gallatin City-County Health Department. Direct contact, ingestion or inhalation of cyanotoxins may irritate the skin, eyes, nose and respiratory system or cause nausea, vomiting, diarrhea or headaches. If you suspect a HAB-related illness in a person or animal call Poison Control 1-800-2221222 and seek medical attention.

Report a suspected HAB at www.hab.mt.gov or call 1-888-849-2938. You may also report a suspected HAB by calling the Gallatin City-County Health Department Environmental Health at 406-582-3120.