Under clear blue skies, 185 volunteer participants fanned out across the Tahoe-Truckee Watershed to take water quality samples from 80 sites in streams, creeks, ponds, and lakes from South Lake Tahoe to Pyramid Lake for the 26th annual Snapshot Day. Organized by Keep Tahoe Blue, Truckee River Watershed Council, Tahoe Water Suppliers Association, and Pyramid Lake Paiute Tribe, this event is made possible by the citizen science volunteers and local laboratories including WETLAB, South Tahoe Public Utility District, Lahontan Regional Water Quality Control Board, and High Sierra Labs. Taken together, the data gathered at this event each May provides a “snapshot” of water quality at a single moment in time for this important source of drinking water and outdoor recreation.

Photo from Katy Jo Caringer

Snapshot Day is one of the longest-running citizen science events of its kind in the nation, beginning in 2001. The volunteers who participate are just as consistent and committed. In Keep Tahoe Blue’s South Shore sampling region, Dr. Larry Green is a fixture. He has taken part in 25 of the 26 years of Snapshot Day. The single missing year was due to the pandemic, when the public did not participate. Eleven-year-old Everett Patterson, son of Keep Tahoe Blue’s Chief Strategy Officer Jesse Patterson, has participated in every Snapshot Day since he was born.

A group of Keep Tahoe Blue’s Core Volunteers sample the same site every year. They have dubbed themselves the “Trout Creekers” and donned custom shirts for this year’s event. One of the team members, Tara Dobyns, rescheduled a trip overseas so she could take part in this year’s event.

“Our volunteers’ dedication to protecting Lake Tahoe is just amazing, and honestly moving,” said Courtney Baumann, Keep Tahoe Blue’s Engagement Manager and the South Lake regional coordinator for the event. “I love Snapshot Day because it creates those strong bonds by directly connecting people with the watershed where they live, work, or play.”

At sites stretching from the Upper Truckee River at Christmas Valley in South Lake Tahoe to Popcorn Rock Beach at Pyramid Lake, volunteers waded into the water to take measurements of characteristics like pH, dissolved oxygen, and electrical conductivity. They also collected samples to be analyzed by laboratories like WETLAB for bacteria, total dissolved solids, and turbidity. Following the event, participants were thanked with a raffle and lunch in South Lake Tahoe provided by event sponsor Lime.

Snapshot Day citizen scientists’ work has rendered a robust water quality dataset stretching back a quarter century. It allows researchers, scientists, and organizations like Keep Tahoe Blue to track changes in important water quality parameters and 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.

Learn more about Snapshot Day at keeptahoeblue.org/ssd and tahoetruckeesnapshotday.org.