By Cara Hollis

The Tahoe Basin is a big, geographic area with diverse and complex ecosystems that all need to be studied, researched, and monitored. This means that there is just too much area to cover for the research teams dedicated to doing the work. To keep eyes on the lake and its surroundings, researchers need residents and visitors to become citizen scientists.

There are a variety of ways people can do this. People can make easy observations and report what they see through the Citizen Science Tahoe and Mountain Rain or Snow apps. Or they can literally get their feet wet after some quick training and take part in Snapshot Day on Saturday, May 21, which is a water quality testing event that happens around the entire Tahoe watershed, from Carson Pass, around Lake Tahoe, down the Truckee River, and ending at Pyramid Lake.

Citizen Science Tahoe is a one-stop shop for all things that need to be monitored in the Tahoe Basin, and the efforts of amateur scientists provide invaluable data to professionals from several different organizations monitoring the lake. Residents and visitors can make simple observations on water quality, the presence of algae, trash problems, invasive species, and storm water runoff issues, as well as get information into the hands of those that need it most.


The app makes reporting easy. Users are offered examples and can choose the one that most closely represents what they are seeing. For water quality and algae issues reported through the app, human observations are compared to data being collected by the UC Davis Tahoe Environmental Research Center (TERC) near-shore network of sensors that are taking physical measurements of clarity and algae.

IDENTIFYING INVASIVES: Citizen scientists receive training on invasive species identification from a League to Save Lake Tahoe representative so that they can make accurate observations on the Eyes on the Lake app. Photo courtesy League to Save Lake Tahoe

“The idea is to calibrate the actual sensor data with human observations,” said Heather Segale, Education and Outreach Director for TERC. “At what instrument level is there something that is observable to people?”

The observations are simple and anyone can do it with just a few moments of time and no experience or scientific background necessary. Just choose from the selection offered by the app. .

“Does the water have a little bit of algae, a medium amount of algae, or a lot of algae?” said Segale of the types of observations that TERC is looking for. “Does the water look brown, cloudy, or turbid?”

What TERC really needs to make meaningful connections between sensor data and human observations is more human observations.

“We need more people at more places around the lake at more times to tell us what they see,” said Segale.

I CAN SEE CLEARLY NOW: Snapshot Day volunteers collect water samples and check results in the field, assisting in the effort to get a reading on the water quality through the entire Tahoe watershed. Photo courtesy Erica Drake/League to Save Lake Tahoe

One success story from the use of the app is on research of metaphyton, a filamentous green alga that rolls along the bottom of the lake and washes ashore in wavy conditions.

“We never used to see metaphyton, but in the South Shore we started seeing a lot,” said Segale. “We were able to get a lot of these observations through the app and it led to a whole new area of research.”

The invasive species, trash, and storm water runoff data collected in Citizen Science Tahoe goes to the League to Save Lake Tahoe, whose mission is the tag line we all know, “Keep Tahoe Blue.”

To help protect against the spread of the two invasive species of aquatic plants already in Tahoe, Eurasian watermilfoil and curly-leaf pondweed, the league collects data from citizen scientists through the Eyes on the Lake section of the app. The Eyes on the Lake is primarily a summertime program, the growing season for invasive species. Citizen scientists can take pictures of the plants, and the app will record their location and get that data back to the people who need it. Those who don’t know what the invasive species looks like can take a training course through the league.

“There is no background in science or botany needed,” says Emily Frey, Citizen Science Program Coordinator for the League to Save Lake Tahoe.

The trainings take place in June, and those interested can register through the events page found on once the dates are set for this year. But if individuals really want to get their feet wet and rub elbows with fellow community members, they can sign up to be a volunteer for Tahoe Truckee Snapshot Day.

Snapshot Day started in 2001 and is designed to get an overall look at water quality through the entire Tahoe watershed. The event is a coordinated effort between the League to Save Lake Tahoe, Tahoe Water Suppliers Association, Truckee River Watershed Council, and the Great Basin Outdoor School, with each organization coordinating testing over different geographic areas. As with the other citizen science opportunities, there is no experience required. Volunteers receive training and all the supplies necessary to test the water, record the results, and collect samples for further laboratory analysis.

“Teams do visual observations and take measurements in the field for different water quality indicators such as pH, temperatures, dissolved oxygen content, and electrical conductivity,” said Frey.

All data collected will be added to the long-term dataset that helps flag any issues that need to be addressed. Those interested in volunteering can learn more, ask questions, and sign up at

THIS IS HOW YOU DO IT: The League to Save Lake Tahoe trains citizen scientists to identify both invasive and native species of plants to Lake Tahoe. This information helps citizen scientists accurately track the spread of invasive species around the lake. Photo courtesy League to Save Lake Tahoe

The Mountain Rain or Snow app got its start under the umbrella of Citizen Science Tahoe, but participants from Tahoe made it such a success that the program was able to extend nationwide and beyond.

“The Mountain Rain or Snow app involves answering a very simple question: What is falling from the sky right now?” said Education Program Manager Meghan Collins, who is leading the engagement strategy for the Desert Research Institute (DRI). “Is it liquid, solid, or something in between?”

While this may not seem like an area of forecasting that requires study, it is more complicated than just assuming there is a clear cut-off at a certain temperature that determines if it is raining or snowing.

“Seeing snow at temperatures of 35 or 37 degrees is not uncommon in arid regions at higher elevations like ours,” said Collins, which makes forecasting snow lines, understanding run-off, and estimating snowpack difficult at best.

Hydrologists and water managers rely on accurate estimates of rain versus snow for their work. An inch of rain is very different from an inch of snow.

Due to complexities of forecasting, NASA is funding Mountain Rain or Snow because it needs the data to improve their estimates of the precipitation phase from their satellite data.

“If you are watching the weather in the winter for skiing or travel, snow levels are very pertinent,” said Collins. “It takes eight seconds to participate. In those eight seconds, people are providing something very valuable to science and ultimately something that feeds back into their lives.”

Mountain Rain or Snow collects data from the Sierra Mountains, Colorado, Oregon, and the Northeastern region of the U.S. Anybody in or near the Sierra is encouraged to participate as the researchers are looking for a variety of elevations and conditions.

How often should observers submit data? “Anytime the perception phase changes or every two hours,” said Collins.

You can sign up to be an observer in the Sierra by texting the word “WINTER” to (855) 909-0798. You will receive instructions and a link to the app. For more information, visit

With these citizen science opportunities, you can help prevent Lake Tahoe and the surrounding areas from being loved to death, no scientific background required.

TESTING FOR CLARITY: A volunteer tests for dissolved oxygen content of the water on Snapshot Day last year. Results from these tests are recorded and used to evaluate the health of the water through the entire Tahoe watershed. Photo courtesy Sam Armanino


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