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Zebra Mussel Information
Zebra Mussel Information

​​Current Conditions

​Highline Lake was opened to boating on April 30, 2023. All boats launching at Highline Lake will be decontaminated upon exit. Boats who have green seals and white receipts from Highline Lake before September 14, 2022 will be decontaminated prior to launching, since any water on board is from before the treatment of the lake with EarthTecQZ. All green seals and blue receipts from Highline from 2023 will be honored upon entrance.​

Current West Ramp hours are 7am - 7pm with the ramp gates locking promptly at closing time. 

What to expect for the 2023 boating season: 

  • Boats launching at Highline Lake will continue to be subject to inspection and decontamination protocols prior to launching. All boats must be clean, drained, and dry prior to launching at Highline Lake. 
  • Upon exiting the lake, all boaters will have their boat inspected and decontaminated and will be issued a blue receipt that indicates it was last used on a body of water with a known aquatic nuisance species.
  • Boaters can expect decreased ramp hours and longer exit wait times when boating resumes at Highline in May. ​​​​​

Detection ​Timeline​Zebra mussels up close

On September 14, 2022 a single adult zebra mussel was detected on an artificial substrate at Highline Lake by the Aquatic Nuisance Species (ANS) Sampling Monitoring Team. 

On October 21, 2022, 5 additional adult zebra mussels were found on a work boat that had been slipped in Highline for the majority of the summer and an additional single adult was found on the west boat ramp.

On October 23, 2022, 3 more adult mussels were found when the east boat ramp dock was removed from the water. 

On November 15, 2022, 2 adult zebra mussels were found in Mack wash below Highline. 

These subsequent detections are indicative of an established population of zebra mussels in Highline and as a result Highline is now considered “Infested” with zebra mussels. Surveys of the Colorado River and Highline Canal upstream of Highline Lake did not provide any evidence to indicate there is an established population upstream of the reservoir.​

Over the winter, Highline Lake was lowered approximately 30 feet to expose areas along and near the shoreline to kill zebra mussels through the natural processes of desiccation and freezing. CPW then applied​ EarthTec QZ, an EPA-registered copper-based molluscicide, to the lake on February 28, 2023 and on March 15, 2023. Results from the treatment are pending and Highline Lake will keep its "infested" status for a minimum of five years.

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