Letter: Tahoe Keys Control Methods Test a collaborative success

Thank you to all who supported and assisted with the Tahoe Keys Control Methods Test. Following a thorough analysis and significant public input, in 2022 the Tahoe Keys Property Owners Association (TKPOA) began a project to test innovative methods to control the aquatic invasive weeds in the Tahoe Keys lagoons. 

Aquatic invasive species pose a serious risk to Tahoe’s water quality and clarity, native species, and the public’s enjoyment of the lake. As we approach the completion of the third year of our Control Methods Test (CMT) project, the TKPOA would like to extend its deepest gratitude to our partners and homeowners who have made this ambitious initiative a success.

The CMT was designed as a multi-year test done in small sections of the Tahoe Keys lagoons as a feasibility study to determine what combination of aquatic weed control methods could be successful in Tahoe based on the principle of a limited application of herbicides. Over the last three years, we have seen an unprecedented level of collaboration, effort, and dedication aimed at controlling the spread of invasive aquatic weeds in the Tahoe Keys Lagoons. We are especially thankful to the Tahoe Regional Planning Agency, the League to Save Lake Tahoe, the Lahontan Regional Water Quality Control Board, and our TKPOA homeowners. Their commitment has been vital in our efforts to move forward with such a challenging, yet essential project.

A special thank you is extended to our lead Scientist Dr. Lars Anderson, project manager, and Rick Lind with his staff at Sierra Ecosystem and Associates, and Committee Chairman Pete Wolcott for their unwavering dedication and tireless efforts. Their leadership has been indispensable to the success of this multi-year project. We are sincerely appreciative of their commitment to coordinating such a complex undertaking. We also extend our thanks to the seventeen independent contractors, along with each agency and organization involved in bringing this all together. Whether through on-the-ground efforts or financial contributions, their support has been vital to the continued progress of this test.

Highlights for the 2024 project

Completion of the third and final year of the CMT later this year: The 2024 CMT focused on testing non-chemical methods as maintenance strategies —UV-Light Treatments, Diver Assisted Suction Harvesting (DASH), Bottom Barriers and Laminar Flow Aeration (LFA).

Extensive Environmental Monitoring: Coordinated actions and communication among all partners allowed for the successful execution of extensive environmental monitoring. Over 150,000 sampling points were recorded and analyzed this year, and this data, along with data from 2022 and 2023, will guide future decisions. Independent sediment sampling and a certified lab analysis confirmed no residual presence of Year 1 herbicides in the lagoons. Both the invasive and native weeds have shown species-specific results and habitat preferences. Our observations from this year, combined with insights from all three years of the CMT test, will help inform targeted treatment methods tailored to each plant’s specific and unique growth patterns.

Reporting and Next Steps: A progress report – the 2024 Implementation Special Report – has recently been published with details that expand on what was specifically done in 2024. The formal Year 3 CMT Compliance Report, which will have extensive data-driven findings, is scheduled to be published and submitted to the basin’s regulatory agencies in March 2025. A comprehensive final report will follow in April 2025 which will summarize cumulative insights from all three years of the CMT. This report will include conclusions and recommendations for scalable, holistic approaches with the overall objective of protecting Lake Tahoe. All reports and updates are accessible on https://tahoekeysweeds.org/ and https://www.keysweedsmanagement.org/.

The collaboration between agencies, experts, and stakeholders has been a remarkable demonstration of how a community can come together to protect our natural resources. The environmental monitoring and treatment techniques tested in the Tahoe Keys have laid an important foundation for future aquatic weed management within the lagoons and throughout the Lake Tahoe Basin.

To all our partners and community members, thank you for your unwavering commitment to this cause. While we still have a long road ahead for long-term management of the weeds in the Tahoe Keys, we look forward to continued collaboration and future shared successes.

- Dave Peterson
Tahoe Keys