A harmful algal bloom warning is in effect at East Wallsburg Bay on Deer Creek Reservoir, and Summit County Health Director Phil Bondurant said his department is actively monitoring Jordanelle, Rockport, and Echo reservoirs for similar blooms.

The Wasatch County Health Department issued the warning on Friday, July 24. It is the only active bloom warning in either Wasatch or Summit County. Under the warning, visitors should avoid swimming, waterskiing, paddling, and drinking the water. Boating is still permitted, and anglers may proceed with caution.

No Summit County water bodies carry a warning or health watch as of July 24, Bondurant confirmed. But Jordanelle Reservoir, where he said Summit County residents are most likely to recreate in summer, is among the three reservoirs his department tests regularly.

"Any time we see bodies of water that don't look healthy … we want to stay out of it," Bondurant said. "Keep your dogs away. Keep your children away. Keep yourself away. Go to a different part of the lake and enjoy where the water appears to be a little bit healthier and a little bit clearer."

What to look for

Lewis Hastings, an environmental expert and emergency response coordinator at the Wasatch County Health Department, said harmful algal blooms typically look like a fluorescent spill of green paint or antifreeze over the water surface. The bright, brilliant green color or sheen is the first sign to watch for.

Not all algae are harmful, Hastings said. But blooms that produce toxins pose the greatest risk to pets and children, who are more likely to drink the water.

Mild exposure causes skin, eye, nose, throat, and respiratory irritation, Hastings said. Ingesting contaminated water at high concentrations can cause abdominal pain and headaches. Severe exposure can result in neurological damage.

Hastings said there have been several reports of pets drinking water where harmful algal blooms were present. Those animals usually become sick, and some have died.

Why now

Harmful algal blooms thrive in heat and direct sunlight, making summer the peak season. They can also migrate across a water body with thermal shifts and wind, Hastings said. The Summit County Health Department warned residents about bloom risks on April 14, noting that warm, sunny, still water with excess nutrients from runoff, fertilizers, or septic systems creates ideal conditions.

Bondurant said Summit County will continue testing water bodies throughout the summer. Residents who spot suspicious algae should report it to the Utah Department of Environmental Quality at (801) 536-4123. A statewide map of all active advisories is available at deq.utah.gov/dwq/recreational-water-quality.