Tackling aquatic invasive plants in the Tahoe Keys

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.

The bottom line is that Lake Tahoe remains at risk until the infestation of invasive plants 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 a portion of a scientific test in the Keys lagoons to determine what technologies and non-chemical methods are most successful at controlling the spread of aquatic invasive plants.

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 in the Keys Lagoons to slow aquatic plant growth and reduce hazardous algae outbreaks starts with laminar flow aeration.

• Laminar flow aeration is a technological solution that injects oxygen directly into a lakebed floor. This process reduces the amount of nutrients available for plant growth and algae blooms.
• If effective, the process of aerating the sediment floor of a lagoon or lake makes it more difficult for aquatic invasive plants to grow back.
• This technology will be installed in early 2019 in the Tahoe Keys Lagoons.
• The League will monitor the project and gather data throughout a three year pilot project to learn if this technology can be effectively applied to other infested areas at Lake Tahoe.

• Lead creation of a long-term integrated aquatic weed management plan for the Tahoe Keys.
• Research, design and test innovative methods to control the weeds in the Keys.
• 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.

• Learn more at the Tahoe Key’s website
• Join Eyes on the Lake
• Donate to Keep Tahoe Blue