Invasive species

Aquatic invasive plants in the lagoons of the Tahoe Keys are growing out of control and are spreading to Lake Tahoe. Unchecked, they threaten to destroy Lake Tahoe’s native ecology, pristine water quality and famous clarity.

A looming threat to Lake Tahoe

The current methods of controlling aquatic invasive plants are not adequate to address the size and complexity of the decades old infestation in the lagoons of the Tahoe Keys, near Lake Tahoe (172 acres of lagoons, which are 90 percent full of invasive plants). These plants spread to Lake Tahoe by attaching to the thousands of boats leaving the Keys every year. New methods need to be tested now and a solution found to stop this assault on Lake Tahoe’s shoreline. The League is engaged and is leading the charge to address this urgent threat.

In the summer of 2019, a comprehensive public engagement process was conducted to gather feedback on the draft plan to test methods for controlling aquatic invasive plants in the Tahoe Keys. The comments gathered, along with other information, formed the October 2019 Scoping Report. Click here to download the report.

Innovate | New combination of methods needed

The bottom line is that Lake Tahoe remains at risk until the infestation of aquatic invasive weeds at the Keys is addressed. Unfortunately, the complexity of the built environment within the Tahoe Keys (docks, pilings, etc.) makes the application of existing control methods impractical and likely ineffective. A combination of approaches for stamping out the weeds and preventing their continued spread is the most likely path to long-term success. The League is working closely with the Tahoe Keys Property Owners Association and other partners to push the envelope on pilot testing innovative methods in the Keys now to identify a solution before it is too late.

In 2017, the League began funding scientific tests and innovative pilot projects in the Keys lagoons to determine what technologies and non-chemical methods are most successful at preventing the growth and spread of aquatic invasive weeds.

Laminar Flow Aeration
Bubble Curtain and Sea Bins

Schematic of combined methods

Containment | Bubble Curtain

It will take several years to test and develop a solution for controlling the massive infestation of aquatic weeds inside the Tahoe Keys. While this process develops it is essential that the Keys problem does not continue to spread to Lake Tahoe. It must be contained...

Stopping the spread into Lake Tahoe: A wall of bubbles

League scientists worked with experts from Canada and the Tahoe Keys Property Owners Association to design, fund and install a custom underwater wall of bubbles or “bubble curtain” across the channel between the Tahoe Keys lagoons and Lake Tahoe. The tiny bubbles dislodge plant fragments from boats passing through the curtain and moves them to the edges of the channel where they can easily be collected and removed. Bubble curtains have been used for decades in other parts of the world for different purposes (aquaculture, control of floating marina debris, etc.) but never for the purpose of preventing the spread of aquatic invasive plants. The hope is that this project can buy Tahoe more time while we figure out a long-term solution. Meanwhile, the League is gathering data on the effectiveness of the bubble curtain to see if it can be a solution for other infested marinas at Lake Tahoe.

Improving Water Quality | Laminar Flow Aeration

Laminar flow aeration is a technology that injects oxygen directly into the lakebed floor assisting a process that reduces organic material and nutrients available for plant growth and algae blooms.
A 5.9 acre installation began operation in April 2019.
The Tahoe Keys Property Owners are operating and monitoring the three-year project and if proven effective it can be applied to other infested areas in the Keys and around Lake Tahoe.

Goals

Stop the current spread of weeds from the Keys into Lake Tahoe by installing containment measures.
Monitor effectiveness and expand successful methods to other infested areas of Lake Tahoe.
Research, design and test innovative methods to control the weeds in the Keys.
Develop a long-term integrated aquatic weed management plan for the Tahoe Keys.

Ways to get involved

Learn more about efforts to control aquatic weeds in the Tahoe Keys
Join Eyes on the Lake
Donate to Keep Tahoe Blue