Toxic algae again strikes Prospect Lake

Colorado Springs officials closed Prospect Lake in Memorial Park on Wednesday until further notice because of what's presumed to be blue-green algae, according to a news release from the city.

A visual inspection was done by Parks, Recreation and Cultural Services staff alongside a water sample test by Colorado Springs Utilities on Wednesday. Testing confirmed the presence of the mycrocystin toxin, produced by cyanobacteria, more commonly known as blue-green algae, according to the news release.

“It is always a difficult decision to close a popular recreational area especially in the middle of summer, but when it comes to the health and safety of the public, it is important that we take all the necessary precautions,” Erik Rodriguez, senior environmental, health and safety specialist, said in the news release sent Wednesday afternoon. “Algae blooms can produce toxins that can be harmful to humans and pets, so we decided to temporarily close the lake until the levels of algae are safe again.”

Colorado Springs reverses decision to close Prospect Lake to motor boats

The city reports that further testing will be done on a weekly basis after a required two-week closure, ensuring that the lake is up to water quality levels before it is reopened.

In 2020, Prospect Lake also closed because of blue-green algae. Since then, measures have been taken including the application of an enzyme-based, non-pesticide treatment that consumes the biomass at the bottom of the lake and helps oxygenate the water.

Confirmed presence of blue-green algae at Colorado Springs lake; closure continues

During the closure, the following activities are prohibited:

SwimmingBathingPaddle boardingTubingWater skiingNon-motorized boating of any kind

No pets will be allowed at the lake. However, fishing areas remain open the public. Anglers are encouraged to clean any caught dish thoroughly and remove all guts.

Prospect Lake reopens for recreational use after toxic algae bloom subsides

Algae background

Blue-green algae is a type of bacteria common in lakes throughout Colorado. Blue-green algae multiplies quickly, especially when conditions are right, such as sustained hot weather, stagnant water and polluted stormwater runoff, city officials said.

These conditions will often result in an excess production of nitrogen, potassium and phosphorus in the water, causing harmful bacteria to grow rapidly. The increased bacteria harms water quality, decreases the amount of oxygen available to animals living in the water, and can produce a toxin that is harmful to humans and pets.

Blue-green algae are self-limiting, naturally-occurring bacteria, meaning that eventually, it will phase itself out of the water.

Looking into the future, Timberline Building Systems will work alongside the city to install an aeration system in the lake this fall, tentatively, to assist with future outbreaks.

Motor boats banned on Prospect Lake — at least short term — in fight against algae bloom