The City of Boulder is escalating efforts to contain an invasive aquatic plant at Boulder Reservoir, pivoting to a labor-intensive removal strategy after a planned herbicide treatment fell through. Officials warn the plant’s spread could threaten recreation and drinking water infrastructure.
Eurasian watermilfoil was first detected in the reservoir in 2022. Since then, it has taken over western coves, extending 10 to 20 feet from the shoreline, according to reservoir manager Stacy Cole. The plant displaces native species, can tangle swimmers and boat motors, and can clog water infrastructure. It may also affect the odor and taste of drinking water.
While Boulder does not currently draw drinking water directly from the reservoir, it remains a backup supply that must be maintained. The reservoir also provides irrigation and drinking water for parts of unincorporated Boulder County…