By Tobi Tyler, Sierra Club

It’s time to take Lake Tahoe’s clarity and water quality seriously and provide long term, holistic solutions to the source of invasive aquatic weeds that are spreading throughout Lake Tahoe from the Tahoe Keys, instead of offering toxic band aid solutions such as herbicides.

Dredging Tahoe’s largest natural wetland to build 1,500 homes and associated canals in the 1960s (now known as the Tahoe Keys) was an ecological disaster, something that would never be approved today. This project destroyed the lake’s natural filtering system (a healthy wetland) and replaced it with artificial canals that are now rife with invasive aquatic weeds (Eurasian milfoil and curly leaf pondweed) and dangerous algae blooms. The Keys’ unnaturally warm water encourages the growth of harmful algae, including deadly cyanobacteria and other non-native species.

To make matters worse, the Tahoe Regional Planning Agency and the Lahontan Regional Water Quality Control Board are moving forward with a proposal by the Tahoe Keys Property Owners Association to treat the Keys’ invasive weeds with aquatic herbicides. However, new non-chemical methods have not been fully tested and shown ineffective as required by the Water Board before resorting to herbicides. Chemical herbicides have never been allowed in Lake Tahoe before because the Environmental Protection Agency classifies Tahoe as a Tier-3 Outstanding Natural Resource Water that cannot be degraded.


To add insult to injury, the above agencies admit using herbicides in Lake Tahoe will never eliminate the weeds; it will only “manage” them. Continued use of dangerous chemicals will be necessary in perpetuity to keep the weeds under control, all for a treatment that will never work to suit the convenience of boat owners in the Tahoe Keys. The agencies are also dishonest by asserting the herbicide use during this “test” would be a one-time event. Every lake in the country where herbicides have been used have had to continue their use once started to keep the invasive weeds down to a manageable level.

So what can be done instead? Returning the lagoons (i.e., the stagnant, dead-end canals) to a healthy, functioning wetland would solve the weed problem by eliminating the warm, shallow waterways that are habitat for just three things: weeds, algae, and boats. The homeowners would keep their houses and only lose their ability to boat to the Lake from their backyards. Is that too large a price to pay to save Lake Tahoe from the Keys? Eliminate the habitat for the weeds and you eliminate both the weeds and need for herbicides. Restoring the canals to wetland would immediately improve the water quality and clarity by filtering nutrients, sediments, and pollution from the surrounding neighborhood of the Keys. Done well, it could enhance the health, beauty, and quality of life at the Keys while saving tens of millions of taxpayer dollars. Natural wetland habitat (and perhaps some boardwalks or hiking trails) in that location would restore wildlife habitat and natural beauty, while enhancing quality of life and opportunities for outdoor recreation.

In the meantime, the Keys should be walled off from the greater Lake Tahoe by installing a barrier in the channel between lake water and the Keys. This short-term solution would help prevent the continued spread of the weeds to Lake Tahoe, which come from the Keys’ boats traveling out to the Lake. Both of these suggestions were ignored by the agencies last year during the scoping phase of this project.

It’s time to stop putting band aids on severed arteries. The Tahoe Keys development never should have happened. But now that they exist, we can heal the damage they continue to inflict on the lake and everyone who lives and visits the region by removing the canals and restoring them to natural wetlands. Attempting herbicide treatment only adds insult to injury at the taxpayer’s expense without solving the problem.

Nature has proven time and again that if we put the pieces back, natural systems will return. A wetland habitat would begin filtering and purifying the waters that feed Lake Tahoe. If we really want to Keep Tahoe Blue, it’s time to restore the canals and lagoons at the Keys.

The Draft Environmental Impact Statement and Environmental Impact Report (DEIS/DEIR), “Tahoe Keys Lagoons Aquatic Weed Control Methods Test” may be found here.

Public comments on the herbicide proposal are being accepted through September 3.

~ Tobi Tyler is the Vice Chair of the Tahoe Area Group of the Sierra Club. She worked for 12 years as a Water Resource Control Engineer for the Lahontan Water Board. Find out more about Sierra Club’s concerns with the herbicide proposal here.


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