The city cited growing concerns over a mussel infestation as the reason for canceling 2019 permits.

WESTMINSTER, Colo. — Growing concerns over a mussel infestation has caused the City of Westminster to ban trailered boats on Standley Lake beginning this summer.

Westminster made the announcement Tuesday, saying that the invasive species has not yet been detected in the city's drinking water supply, but "a recent review of the policies and methods used to prevent an infestation found decontamination is not fully effective for many trailered boats."

Zebra and quagga mussels are a non-native aquatic species that have the potential for significant damage.

They are a growing threat to Colorado water resources because once they are established in a body of water, they decimate local ecosystems. They also clog potable water infrastructure and cause algae blooms that threaten water quality, Westminster said.

Westminster added that data from 2018 found 24 instances where people boating in Standley Lake deliberately bypassed protective measures.

Max Kirschbaum, department director for Westminster Public Works and Utilities, said Standley Lake provides drinking water for about 300,000 residents in Westminster, Northglenn and Thornton.

"Water comes directly from the lake into our treatment system," Kirschbaum said. "If these mussels establish themselves in the lake, there would be significant, on-going costs to keep our system running. Protecting our community’s water supply will always be the chief concern."

Westminster said it will issue a full refund to anyone who purchased a 2019 permit, which will be canceled.

No additional permits will be sold. Permits can still be purchased for non-trailered watercraft such as kayaks, canoes, rafts and paddleboards. Those types of watercraft will still have to go through the city’s on-site decontamination procedure.

Decontamination involves spraying all surfaces of a vessel and conducting a visual inspection to ensure zebra and quagga mussels are not present.

Jason Genck, director of Westminster Parks, Recreation and Libraries – the department that manages Standley Lake recreation facilities and permits – said the city does not have a timeline for when it will lift the ban.

"Until we can determine if there’s a way to ensure these types of boats won’t pose a substantial risk at the lake, we need to put these activities on hold immediately and indefinitely," Genck said.

A meeting has also been scheduled for Tuesday, April 2 from 6:00 -7:30 p.m. in the community room at the City Park Recreation Center at 10455 Sheridan Blvd. City staff will be there to discuss the decision and answer questions from the boating community.

Standley Lake Regional Park Protecting your water supply is an essential priority. After a thorough review of policies in place to prevent invasive zebra and quagga mussels from entering Standley Lake, the City is indefinitely...