Aquatic Invasive Weeds in the Tahoe Keys

 
Aquatic weeds, unintentionally introduced by humans, have taken over more than 90% of the Tahoe Keys’ lagoons. These problem plants are growing out of control in the Keys and are spreading into Lake Tahoe proper. Left unchecked, aquatic invasive weeds threaten to destroy Lake Tahoe’s native ecology, pristine water quality and world-famous clarity.

A proposal to test a suite of methods to control the invasive weeds problem is currently moving through a thorough environmental review process. Click here for more information about the Tahoe Keys Lagoons Aquatic Weed Control Methods Test.

Read the League's official comment letter on the proposed test and our op-ed in the Reno Gazette Journal.

Tahoe Keys
Since 2013, the League has been deeply involved in addressing the infestation of aquatic invasive weeds in the Tahoe Keys – ground zero for the problem at Tahoe. With a consistent, credible voice, the League has collaborated, innovated and funded cutting-edge treatments for the invasive weeds problem in the Keys.

To overcome the aquatic weeds problem in the Keys – and safeguard Lake Tahoe for the long term – the League is focused on three goals: CONTAIN, TEST & CONTROL.

Contain
While a sustainable, long-term solution to the invasive weeds problem is developed, the League is working to contain the problem and prevent Lake Tahoe from becoming choked with aquatic invasive weeds.

Bubble Curtain & Sea Bins 
In 2017, the League began funding scientific tests and innovative pilot projects in the Keys lagoons. 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 west channel between the Tahoe Keys lagoons and Lake Tahoe. In early 2021, a second bubble curtain will be installed across the east channel connecting the Tahoe Keys Marina to the Lake.

This technology mimics the bubble nets humpback whales use to corral and catch prey. In this case, the bubble wall blocks fragments from leaving the Keys lagoons by dislodging them from passing boats and corralling them to the edges of the channel. There, the fragments are easily collected and removed by the seabins, which act as floating trash cans.

 


Eyes on the Lake
Our citizen science program trains volunteers to identify and report aquatic invasive species using a smartphone app, which is free to downloaded here. The League has been training Tahoe Keys Property Owners Association members for the past seven years, giving them the tools to monitor and report on the problem at their back doors.

 


Boat Backup Station
Aquatic weeds can get tangled in boat propellers and carried into the Lake. The League supported the creation of a mandatory boat backup station for boats exiting the west channel of the Keys. By reversing their propellers, weeds are dislodged inside the Keys before they can hitch a ride into the Lake.

Tahoe Keys - Boat Backup Station
Test

While progress has been made in containing the spread of invasive weeds, the tools we have now are not sufficient to overcome the massive, 172-acre aquatic weed infestation in the Tahoe Keys lagoons. We need to test innovative and proven tools that have been shown effective elsewhere to get the right combination for long-term use across the Keys lagoons. Click here for a virtual tour through of the Tahoe Keys weed problem.

Tahoe Keys Virtual Tour
A plan for a Control Methods Test is now moving through a rigorous, science-based environmental review and public consultation process. This proposed plan is not a full-scale project. It’s a limited, strictly controlled and tightly monitored test to learn what will work as a long-term management approach. Crucially, the test will not be allowed to proceed unless Lake Tahoe and the people who enjoy it remain safe and healthy.

We must act now. The problem will intensify the longer we delay.

  • To read the complete Draft Environmental Impact Report/Statement (DEIR/S) for the Control Methods Test, click here.
  • For detailed information about the Control Methods Test, visit tahoekeysweeds.org.
  • Click here for the League's official comment letter on the DEIR/S for the Control Methods Test.
Control
Though containment mechanisms are now in place, for years invasive weeds moved from the Keys into the Lake unimpeded. As a result, there are now over 100 acres of infested area just outside the Keys, making up the largest population of invasive weeds in Lake Tahoe proper. This infestation is being called the "Tahoe Keys Complex."

Invasive weeds spilling into Lake Tahoe


This photo of weeds creeping out of the Tahoe Keys and into the Lake itself illustrates the immediate threat to the Lake's clarity and delicate ecology. For years, the League has advocated for the immediate removal of the Tahoe Keys Complex. In October 2020, our efforts came to fruition when active treatment of the densest growth in the Complex started using SCUBA diver-assisted suction dredging. The League provided a donation that unlocked public funding to start the weed removal.

The photo below, taken in November 2020, shows that suction dredging was effective in eradicating nearly all of the weeds in this heavily infested area. With additional support and advocacy from the League, treatment of the Tahoe Keys Complex will continue in 2021.


Tahoe Keys Virtual Tour

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