The swim beach at Boulder Reservoir has been temporarily closed after city staff observed what could be a harmful algae bloom in the reservoir on Saturday morning. Visitors are also asked to keep dogs out of the water.

In a press release, the City of Boulder said that samples have been collected for testing and that the swim beach was closed “out of an abundance of caution.” City staff will monitor algae bloom tests overnight and updates will be available tomorrow, according to the press release.

Community members can text the keyword “BPRReservoir” to 888-777 or check the webpage BoulderRex.org for operations updates.

Although the swim beach is closed, the reservoir is still open to watercraft use via entry through the main gate. However, watercraft users should avoid contact with the water in areas that look like they are inhabited with potential harmful algae and be cautious.

According to the press release from Boulder, harmful algae blooms can look like thick pea soup, spilled bluish-green paint on the water’s surface, a thick mat of foam along the shoreline or short grass clippings.

The release also noted that Boulder Reservoir is not currently being used as a drinking water supply as it is only used as a water source for the city periodically.

Find more updates and information here.

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