A multi-partner collaboration: Finding solutions to control and prevent aquatic weeds in the Tahoe Keys lagoons and protect Lake Tahoe

The Problem

There is growing concern about the spread of aquatic invasive and nuisance plant species which cover over 90 percent of the Tahoe Keys lagoons.  Despite the considerable management and financial investment of the Tahoe Keys Property Owners Association (TKPOA) to control this problem, weeds continue to spread and management costs continue to mount.

History & Background

Tahoe Keys curlyleaf pondweed distribution map, 2018

Aquatic weeds have spread to many areas around Lake Tahoe, creating urgency that lake-wide collaboration is needed to control aquatic invasive species (AIS).  The 2015 Lake Tahoe Aquatic Invasive Species Implementation Plan lists the Tahoe Keys lagoons as the highest priority areas for control of AIS in Lake Tahoe, as the largest and most persistent population of aquatic weeds grow in this location, infesting over 172 acres of waterways.  All other lake-wide infestations combined account for approximately 20 acres.

Map of AIS Control Work

Environmental Impact Studies Triggered


TKPOA submitted the Tahoe Keys Lagoons Aquatic Weed Control Methods Test Application, triggering the need for an Environmental Impact Report (EIR) required by the California Environmental Quality Act (CEQA) and Lahontan Regional Water Quality Control Board (Lahontan Water Board), and an Environmental Impact Statement (EIS) required by the Tahoe Regional Planning Agency (TRPA).

The Control Methods Test application proposes the use of targeted herbicides as one weed control method to test along side and in combination with other methods to reduce and control the abundant growth of invasive and nuisance aquatic weeds that are compromising water quality and degrading beneficial uses of the Tahoe Keys lagoons, as well as threatening the future ecosystem and water quality of Lake Tahoe.

The environmental analysis will determine if the use of U.S. Environmental Protection Agency (EPA) and the Department of Pesticide Regulation (DPR) approved herbicides can meet the strict environmental standards of Lake Tahoe’s classification as a Tier Three, Outstanding National Resource Water.

Access the most recent project updates and details HERE.


A Collaborative Multi-Stakeholder Process


The goal of the collaborative, multi-stakeholder process is to ensure stakeholder concerns and perspectives are addressed during the environmental analysis, resulting in a plan for testing weed control methods that is science-based, broadly supported, and effective at controlling aquatic weeds in the Tahoe Keys lagoons.

TRPA, one of the lead agencies on this project, convened a core committee of stakeholders to select neutral facilitation services and an independent environmental consulting firm for the environmental analysis process.  The selection team was composed of representatives from Lahontan Water Board, TKPOA, TRPA, Tahoe Water Suppliers Association, and The League to Save Lake Tahoe.  The core team unanimously selected Zephyr Collaboration to provide facilitation services for the project, and TRC Solutions, Inc. to provide environmental consulting services.

As a first step in designing a collaborative process, an assessment of stakeholder interests, concerns and questions was completed by Zephyr Collaboration in October 2018.  The Stakeholder Assessment Report summarizes various stakeholder interests and perspectives, and includes recommendations for a collaborative, transparent, inclusive stakeholder process to inform the Environmental Impact Statement/Environmental Impact Report (EIR/EIS) and decision makers in what has been described as one of the biggest environmental challenges facing Lake Tahoe.

Read the Stakeholder Committee’s December 2021 Final Report

This website is hosted by Zephyr Collaboration with the aim of sharing the work of the collaborative Stakeholder Committee, while serving as an information resource for the public. Please visit often for updates and opportunities to provide input and feedback.