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100 citizen scientist volunteers gather water quality data for 24th Snapshot Day

League to Save Lake Tahoe
May 13, 2024

LAKE TAHOE, Nev./Cal., May 13, 2024 – On a sunny Saturday morning, 100 volunteer participants fanned out across Lake Tahoe’s South Shore to take water quality samples from 34 streams, creeks, ponds, and lakes to monitor the health of the Truckee River watershed and Lake Tahoe as part of the 24th annual Snapshot Day. They were joined by teams doing the same tests simultaneously in other regions of the watershed. 

Since 2001, Snapshot Day partners have sampled sites from Meyers to Tahoe’s North Shore, on to Truckee and through Reno, terminating at Pyramid Lake. By collecting water quality data from the same sites each year, the League to Save Lake Tahoe and event partners can track changes in the health of Lake Tahoe and the Truckee River watershed. For the past eight years, the League has focused on the upper watershed, which includes the headwaters of the Upper Truckee River and dozens of water bodies across the South Shore. 

“What was surprising is just how much goes into monitoring all the different tributaries that go into Lake Tahoe,” commented Ian Walter, a first-time participant in Snapshot Day. 

As volunteers waded into marshes and streams to take measurements of characteristics like pH, dissolved oxygen, and electrical conductivity, they became “citizen scientists” for the day, contributing important environmental data. They also gained a deeper understanding and connection to the watershed where they play, visit, live, and work. 

“I think it’s important for us to do our part. Especially if we love a place, it’s up to us to protect it,” said Aislinn Kari, another first-time Snapshot Day volunteer who made the journey from Reno to join in. “Being a part of this and feeling as if I contributed something, it just feels good.” 

With the addition of this year’s sampling, there is a robust water quality dataset stretching back nearly a quarter century. It allows researchers, scientists, and organizations like the League to track changes in important water quality parameters, as well as gain a better understanding of how the Tahoe ecosystem responds to environmental shocks like droughts and wildfires. The data analysis can also guide planning for ecosystem restoration projects and other efforts that make the Tahoe environment more resilient in the face of climate change.

“Since 2001, the water quality data collection and field assessments for Snapshot Day have played an integral part in telling the story of Lake Tahoe’s health,” said Deirdre Francks, Science and Data Coordinator from the League to Save Lake Tahoe. “Next year, for the 25th year of the event, we are going to compile a larger report highlighting the story of Lake Tahoe, its clarity, and the volunteers that ensure it remains healthy for future generations.”

In addition to water quality tests conducted by citizen scientists in the field, samples are also taken to a lab to be analyzed for bacteria, total dissolved solids, and turbidity by generous event partners from the South Tahoe Public Utility District and Lahontan Regional Water Quality Control Board.  

Snapshot Day partners look forward to analyzing this year’s data and sharing findings with the public in the coming months. Learn more about Snapshot Day at and



Media Resources: Photos and videos 

Media Contact:
Chris Joseph, Communications Director, League to Save Lake Tahoe

The League to Save Lake Tahoe, also known by its iconic slogan “Keep Tahoe Blue,” protects and restores the Tahoe Basin’s unique natural beauty and environmental health—today and for future generations. Guided by science, we develop innovative solutions to complex environmental problems, mobilize thousands of volunteers each year, and act as both watchdog and advocate for Tahoe’s wellbeing. Learn more about our 67-year-old, 501c3 organization at 

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