Aquatic invasive plant species confirmed at Boulder Reservoir
Dec. 9—A survey by Colorado Parks and Wildlife has confirmed that an invasive plant is now established at the Boulder Reservoir.
CPW first detected the presence of Eurasian watermilfoil in the reservoir this summer, according to a news release from the city. Then during an additional survey this fall, CPW confirmed its establishment.
The plant is not harmful to public health, and at its current growth levels, there are no impacts to recreation use at the reservoir or its use as a regional drinking water supply, the release said.
EWM is established primarily along the western coves of the reservoir, as well as in areas along the southern and northern shorelines, the release said. The density of EWM is currently low near the swim beach and drinking water intake areas. If it becomes very dense, the plant could impact swimming and boating and cause taste and odor issues with drinking water.
"While the survey confirmed the presence of EWM at the reservoir, we don't know how it arrived," said Parks and Recreation Director Ali Rhodes in the news release.
"It can easily be transported by wind, connected waterways, humans fishing, dogs, watercraft, or wildlife, so we encourage anyone who recreates in the water to be vigilant about checking for aquatic nuisance species. The survey did find that there are no other aquatic nuisance or invasive plant species in the reservoir, which is good news."
Upon initial detection of the plant, the city adjusted operations to include exit inspections on watercrafts, increased education to users and added notification signage, the release said. Because the current impact of EWM is low, the city and Northern Colorado Water Conservancy District are not planning to make any additional changes to the water supply operations or recreational activities beyond changes made this summer.
Eradication of EWM from the reservoir is unlikely if not impossible since EWM can reproduce and establish from just one fragment, the release said.
Jeff Stahla, spokesperson for the Northern Colorado Water Conservancy District, said this is the first time this species has been found in northern Colorado reservoir supplies. He added that while Boulder and CPW are taking the lead on the project, the Northern Colorado Water Conservancy District will be involved in monitoring the species.
"We deliver water from Carter Lake to Boulder Reservoir, so we will certainly be watching in terms of what they find at the reservoir," he said. "This is an issue that certainly will capture the attention of water managers throughout the region."
More information will be posted at boulderparks-rec.org and bouldercolorado.gov/locations/boulder-reservoir.
