By Michael Abeyta

AURORA, Colo. (CBS4) – On one of the hottest weekends of the year, the swim area at Cherry Creek State Park is closed. That’s because of blue-green algae blooms in the water that can be harmful to people and pets.

File photo of the swim area at Cherry Creek State Park (credit: CBS)

Summer in Colorado provides the right conditions algae bloom, but most types of algae are okay.

“Algae is natural in Colorado waters. Most of it is harmless, and actually a very important part of the aquatic food chain,” said Jason Clay the Public Information Officer for Colorado Parks and Wildlife.

(credit: CBS)

Blue-green algae, however, can be toxic if there is too much. It can make people and pets sick. At the Cherry Creek Reservoir, they currently have a large bloom which is why they decided to close the swim area.

“We’re rapidly monitoring and testing our waters so when those toxins are elevated in numbers then we close down areas just for precaution or safety,” said Clay.

The swim area being closed didn’t stop people from getting in and on the water in other parts of the park.

(credit: CBS)

The off leash dog area is so far free of algae, but if you are in the park, the best way to keep yourself and your pets safe is to stay on dry land.

“Don’t let your pets get in the water. Don’t let your kids get in the water. Don’t ingest any of that water,” Clay said.

The blooms form as a result of a number of things including warmer temperatures, stagnant waters, and nutrient loading from fertilized lawns. For more information on blue-green algae, click here.

Michael Abeyta