Lake Tahoe’s geological history underscores the ecological and cultural significance of this incredible place. Recent research shows that Lake Tahoe first took shape more than 2.3 million years ago, making it the oldest lake in North America and the third oldest waterbody in the world. We also recognize the importance of the native Washoe people, who have served as the original and current stewards for 10,000 years. Today, we continue this legacy of stewardship through science-based environmental protections.

Last month, the Tahoe Regional Planning Agency (TRPA) released a comprehensive, four-year report on Lake Tahoe’s environmental health. The peer-reviewed report highlights significant progress throughout the Lake Tahoe Region in preserving this national treasure and outlines critical challenges where continued collaboration and action are needed. This draft Threshold Evaluation Report marks our eighth assessment, covering 140 standards across ten categories, including water and air quality, transportation, wildlife, forest health, and more.

During the four-year reporting period, nearly 80 percent of environmental standards assessed were in attainment. Notably, TRPA and our partners surpassed a landmark goal to restore or enhance 1,100 acres of Lake Tahoe’s wetlands. For more than 40 years, partners in the basin have pursued this goal, underscoring our commitment to revitalizing wetland areas damaged by past development.

These accomplishments are a testament to the collaborative work of more than 80 organizations and citizens alike participating in the Lake Tahoe Environmental Improvement Program (EIP). Since 1997, the EIP has been instrumental in accelerating threshold attainment through public and private investments in projects such as stormwater infiltration, wetland restoration, defensible space, forest fuel reduction, and biking and walking paths that enhance environmental conditions and provide lasting community benefits.

In addition to our progress, the evaluation highlights several challenges. The increasing frequency and intensity of wildfires within and around the Tahoe Basin impacted air quality standards for short periods. In 2021, over 1.5 million acres burned across the Sierra Nevada, with wildfires like the Caldor and Tamarack Fires introducing heavy smoke and ash into the watershed. While not every air quality standard can be managed from inside the Tahoe Basin, the Caldor Fire also tested our collaborative forest management and defensible space strategies, which made a difference for firefighters and helped save Lake Tahoe. In this new era of extreme weather and megafires, we must continue to strengthen regional coordination of forest resilience and community wildfire protection projects.

In the lake itself, the discovery of invasive New Zealand mudsnails in 2023 poses a new threat to our ecosystem. Researchers are reporting an alarming increase in Lake Tahoe’s temperature, which can make invasive species even more difficult to control, emphasizing the need for enhanced monitoring and preventive measures.

Another critical factor in preserving our environment is how we move around the basin. Regional transportation partners met our new standards to reduce vehicle use during the reporting period, but we recognize that to further reduce reliance on our cars the region’s transportation system needs continued investment. Local governments are already working together to reduce congestion and protect air and water quality. In 2022, the free LakeLink microtransit service launched on the South Shore, filling a key gap in the transit system. Together with TART Connect on the North Shore, microtransit has provided 1.4 million riders with free, on-demand service. Combined with traditional transit, local investment reached nearly $8.5 million last year, the highest level of transit funding in the basin’s history.

While we have seen substantial strides in the basin, this work is far from complete. Emerging challenges, such as the effects of extreme weather on lake clarity and the threat of invasive species, require innovative solutions, new research, and sustained partnerships to address them head-on.Over the coming months, TRPA will be collecting public and partner input on the draft Threshold Evaluation Report, and will present a final report and recommended actions to the TRPA Governing Board in June. The threshold evaluation summary, underlying data, and a feedback survey are available at thresholds.laketahoeinfo.org.

The recent findings on Lake Tahoe’s true age lend some perspective to this work. Rather than diminishing our shared progress in the basin, the knowledge underscores the significance of each step forward. We look forward to working with everyone to continue protecting and restoring this spectacular place for generations to come.

-Julie Regan is Executive Director of the Tahoe Regional Planning Agency.