City officials said Thursday that Sloan’s Lake is closed to visitors because of an increase in blue-green algae blooms.
The park area remains open, but contact with any lake water is banned due to an increase in potentially deadly algae. This is the first time Denver Parks and Recreation employees can recall the closure of a lake in Denver for this reason, spokeswoman Cindy Karwaski said.
The blue-green algae, or cyanobacteria, were first discovered in the lake earlier this month, and public health officials posted warning signs around the lake asking visitors to avoid contact with the water. Now, they’ve replaced them with cessation signals due to increased toxin levels.
Although it happens every year, Karwaski said the continued heat has caused higher than normal levels, causing algae to bloom and grow. Usually algae stop growing at 77 degrees.
“We just want to encourage people to avoid the water,” she said.
People and pets are asked not to get in or near the water in the park, and activities such as fishing, wading, boating, canoeing, paddleboarding, and kayaking are prohibited. Ingesting algae can poison pets, livestock, wildlife, birds, fish, and humans. It is so toxic that pets can die within hours of drinking the water, and humans can become ill and suffer headache, diarrhea, weakness and liver damage.
When algae blooms and cyanotoxin levels are depleted, the lake is expected to reopen.
Karwaski said the city is still using the lake’s water to irrigate the surrounding park because testing has not found the toxin in the water used for irrigation. The water is taken from the bottom of the lake, which is cooler, while the algae bloom occurs higher up in the warmer area. However, park staff continue to test the water before using it, she said.
If you or a pet comes into contact with water, you should seek medical attention.