Tuesday, October 5, 2010

Successful removal of aquatic invasive weeds in Lake Tahoe


From Tahoe Resource Conservation District:


South Lake Tahoe, Calif. – Efforts to remove approximately one-third of the Eurasian watermilfoil infestation in Lake Tahoe’s Emerald Bay using experimental technologies has been deemed an early success.


Eurasian watermilfoil is a fast-spreading aquatic invasive weed that has been on the rise in Lake Tahoe since its introduction more than a decade ago. A partnership including Tahoe Resource Conservation District, California Department of Parks and Recreation, Tahoe Regional Planning Agency, UC Davis Tahoe Environmental Research Center and subcontractor A.C.E. Diving covered approximately 8,500 square feet of lake bottom near the pier and swimming beach of Emerald Bay using 8’ x 40’ reusable bottom barrier strips in June and hand removal of remaining weeds. On Sept. 14, the barriers were removed to reveal just sand, with no signs of invasive weeds below the barriers.


The project’s objective was to focus efforts on the removal of a significant portion of one known, discreet infestation site, with the goal of completely removing all visible plant growth.


According to California Department of Parks and Recreation Environmental Scientist Dan Shaw, “We’re very optimistic about the initial results of this pilot project because it demonstrates that it is possible to eradicate the majority of an infestation in a specific locale. These findings will help us establish a control plan for aquatic invasive weed populations in Emerald Bay and other afflicted areas of Lake Tahoe.”


Participating resource managers are implementing a prioritized strategy for the effective removal of aquatic invasive weeds based on risk of spread, previous removal projects, public benefit and likelihood of removal success. The swimming beach and pier area in Emerald Bay was identified for the pilot project because it meets all of these criteria. Surveys will be conducted in subsequent seasons to document the long-term success of the removal efforts. It is anticipated that future control efforts will only require more limited maintenance removal to keep the swim beach and pier free of aquatic invasive weeds, greatly reducing control costs.


It is estimated that 3 acres of Eurasian watermilfoil have established in three distinct locations within Emerald Bay, near Parson's Rock, the Swim Beach and Avalanche Beach.

For more information, visit http://www.tahoercd.org/.