Q: What are the Tahoe Keys?

A: For the purposes of the Integrated Management Plan and Nonpoint Source Water Quality Management Plan, the Tahoe Keys is a development complex, which includes seven primary private and public landowner groups. This includes a nonprofit residential association (Tahoe Keys Property Owners Association) comprised of 1,529 homes and townhomes, a commercial marina, a medium sized commercial business center, a nonprofit dock and boat moorage association, the privately owned Lake Tallac and the nonprofit California Tahoe Conservancy.

Q: What is the Tahoe Keys Property Owners Association?

A: The Tahoe Keys Property Owners Association (TKPOA) is a private community connected by 11 miles (172 acres) of interconnected waterways. The Tahoe Keys is located at the southern tip of Lake Tahoe in South Lake Tahoe, California. Most of the 1,500+ members who own homes, townhouses or vacant lots have a private boat dock and are located on its lagoons.

Q: What are the aquatic invasive plants in Tahoe Keys, and why are they a problem?

A: Aquatic invasive species including Eurasian watermilfoil and curly leaf pondweed, along with the native nuisance plant coontail, make up the bulk of the problem in the Tahoe Keys. They interfere with native species, harbor non-native fish species, create mosquito habitat and interfere with boating and other recreation. Click Here for more information on the AIS in the Keys.

Q: How did these plants get into the Tahoe Keys? Where did they come from?

A: Both invasive species are native to Europe and Asia, with Eurasian watermilfoil likely being introduced in the 1980s - curly leaf pondweed some time after that (first recorded in the Tahoe Keys in 2003). No one knows how they were introduced, but it is likely from home aquarium dumping or transported via boat.

Q: How are environmental and regulatory organizations involved in this process?

A: We have been engaging local and regional agencies and stakeholder groups throughout the process for more than five years now, keeping them apprised of the planning process, jointly performing studies, and investigating proposed methods of weed management. Ultimately, the Plan will need to be approved by the Lahontan Regional Water Quality Control Board.

Q: Why is the Tahoe Keys Property Owners Association preparing the Plan?

A: TKPOA has been investigating long-term solutions to the weed problem since 2007. The severity and cost of the weed problems in the Tahoe Keys, combined with TKPOA’s support of regional efforts to maintain and improve the quality of the Tahoe Keys and Lake Tahoe for its members, along with the predominately private land ownership of the Tahoe Keys, prompted TKPOA in 2012 to begin preparing a Plan in cooperation with numerous public agencies, interest groups and other landowners. In 2014, the Lahontan Regional Water Quality Control Board made the Plan a formal requirement.

Q: Can the Tahoe Keys just use only bottom barriers to eliminate the problem?

A: Plants can easily grow on the barriers unless they are cleaned or removed and replaced every year. Experiments testing the barriers in the Tahoe Keys also showed that watermilfoil begins to inhabit the sediment that deposits over time on the bottom barriers. And curlyleaf pondweed does not require roots to grow, reproduce, or expand, thereby making bottom barriers of limited effectiveness for the highest threat invasive plant. A significant portion of the lagoons cannot be treated with barriers effectively due to the presence of hundreds of structures like docks, pilings and platforms (divers would have to work the barrier mats around these obstructions in turbid water). From a practical standpoint, widespread use of bottom barriers is not effective due to boat traffic that dislodges bottom barriers, which then become a safety hazard. For these and other reasons it has been estimated that complete coverage of the Tahoe Keys with bottom barriers, including placement, maintenance and removal, would cost more than $40 million.

Q: Can the Tahoe Keys be drained to eliminate the problem?

A: Realistically, no, due to a combination of variable waterway depths, structural threats to bulkheads, local groundwater conditions, seed bank of invasive species present in the sediments evolved to tolerate drought, the amount of energy/pumping required, and the need to filter, treat and dispose of the aquatic animals/plants/waters drained from the waterways. From a groundwater perspective, because the Tahoe Keys lands are built on highly porous materials (sand), draining the waterways is likely not possible. With the environmental impacts, prohibitive costs, problematic groundwater conditions, extensive seed bank in the sediments, and economic/recreation impacts of this method, draining is considered infeasible. Again, for curlyleaf pondweed, turions have evolved to survive extended drought periods and would come back even after drying the lagoons.

Environmental Catastrophe: Aquatic Invasive Weeds