With the weekend forecast calling for storms and cooler temperatures, the beginning of the end is in sight for Utah’s 2017 crop of toxic algae, yet the poisonous critters are apparently seeking an encore.
Authorities issued several new advisories on Utah’s waterways in recent weeks due to presence of toxin-producing algae, or the poisons they are known to release. Health departments are urging limited use of Mantua Reservoir, Ogden City’s 21st Street Pond and part of Deer Creek Reservoir near the Deer Creek Island Resort in Heber, while most of Utah Lake and portions of the Jordan River also remain under warning advisories.
The waterways are open to the public, but visitors are warned to avoid direct contact through swimming or other sports. Pets and small children should be kept away to prevent them from drinking affected waters.
With the exception of the one on Utah Lake, most of the active blooms remain small. Preliminary tests at Deer Creek Reservoir indicated high levels of the liver toxin microcystin, but only in a limited area. Microcystin is known to cause gastrointestinal distress when ingested.
The affected area is not located near intakes that collect drinking water from Deer Creek Reservoir, said Chris Smoot, a public information officer for the Wasatch County Health Department.
It is, however, located near a beach area, so the department has posted signs indicating which areas swimmers should avoid, Smoot said.
Smoot said the bloom appeared to be breaking up on Thursday due to choppy conditions on the reservoir.
Though difficult to predict, on the whole, this season’s blooms seem to be on the decline, according to Bon Holcomb, harmful algal bloom program coordinator for the state Division of Water Quality. Concentrations of algae and toxins at Utah Lake have decreased, Holcomb said, and the weather expected this weekend should prevent additional blooms from developing.
This summer’s has seen an unusually long period of algal growth on its waterways, particularly on Utah Lake, Holcomb said, though a new pattern seems to have emerged over the last two years that sees even large blooms “fizzle out” in September.
“Unfortunately that also coincides with the recreational season,” Holcomb said, “but sometimes we get some nice days in October.”
“It may be a new normal,” said Jodi Gardberg, who oversees technical services, including algal bloom monitoring, for the state Division of Water Quality. “We had an unprecedented year last year, and this year we have warnings on some similar water bodies. But we also had very hot temperatures this year and last year.”
Grant Koford, director of environmental health for the Bear River Health Department, said he expected the bloom at Mantua Reservoir would be short-lived. The reservoir developed toxic algae last year as well, he said, but as soon as the temperatures started to cool down, it was gone.
The current bloom, which contained levels of microcystin slightly above the threshold at which the state recommends a health advisory, is unlikely to worsen, Koford said.
“I don’t think there is going to be a closure,” he said, “because of the moderation in temperatures this week.”
Some are critical of the state’s handling of algal bloom advisories this year. Eric Ellis, executive director of the Utah Lake Commission, said the criteria for a “warning” are too broad, and the difference between a warning-level advisory and a closure is not clear to the public.
“The EPA has issued, and the state has adopted, a set of thresholds that are very cautious,” Ellis said. “And so this summer, for example, it has been frustrating for lake lovers like myself and lake users that this new threshold is as cautious as it is.”
Water samples collected on Utah Lake this year barely exceeded the state’s warning thresholds, Ellis said.
Ellis urged the state to adopt a system of risk assessment, and produce more nuanced advisories. For example, he said, at low levels, the presence of algal toxins might be dangerous only for small children and pets unaware they shouldn’t drink lake water, while adults could safely recreate without experiencing problems.
Many lake’s patrons aren’t aware of that warning-level advisories do not prohibit recreations but rather only caution visitors against direct contact with the water, he said. Consequently, the summer-long warning drove business away from Utah Lake this year.
“It’s a warning advisory, not a closure,” Ellis said. “But no one knows what that means, so they assume it’s a closure.”
But Gardberg, with the state Division of Water Quality, defended the warning system and said she believed health departments across the state had made “very good decisions,” based available indicators.
The warnings are intended to offer advice to recreational users on staying safe, said Gardberg, who nonetheless acknowledged the impact algal blooms can have on recreation-related businesses.
“When…an advisory is issued, business goes down, and that’s the economic effect of” toxin-producing algae, she said. “It’s unfortunate.”
Even though bloom warnings remain in effect, Ellis encouraged Utahns to visit Utah Lake for safe activities, such as boating.
“There’s beautiful scenery with the fall colors right now,” he said. “Sailing opportunities, boat rentals — there’s so much to enjoy regardless of whether we have blooms or not.”