19th annual Snapshot Day to unveil conditions in Lake Tahoe and Truckee River

For the past 18 years, volunteers have been monitoring water quality conditions across the Lake Tahoe and Truckee River watersheds, collecting data at a single point in time to better understand the area as a whole. It is a bi-state collaborative that can achieve a larger watershed approach to successful data collection.

On May 17 and 18, 2019, volunteers will once again head out and perform a variety of tests including temperature, pH, conductivity, dissolved oxygen, turbidity, algae, and nitrogen.

On the 17th volunteers will test along the Lower Truckee River in Nevada and on May 18 for the other sites in Truckee, South Lake Tahoe and North Lake Tahoe, from 9:00 a.m. to noon each day.

Volunteers wishing to participate are invited to RSVP (http://ow.ly/Il1t30nlhmh) and join in efforts. No experience is necessary, and all are welcome to attend.

In 2018 365 volunteers were part of 84 teams along both the north and south shores of Lake Tahoe and the middle and lower reaches of the Truckee River. They made observations, took photos, did measurements and took samples.

One positive finding was that only 22 percent of the sites monitored in 2018 showed elevated levels of turbidity, down from 30 percent of the sites in 2017. Turbidity is a measure of the water’s cloudiness and an indicator of the presence of fine sediment pollution, the leading cause of clarity loss in Lake Tahoe.

“This is a positive trend and one we hope continues in 2019. But it needs to be tempered by the fact that prior to this, we had four years of drought followed by a big winter in 2017 and significant spring runoff,” said Emily Frey, natural resources associate for the League to Save Lake Tahoe. “Measuring consistently year after year is critical for getting an accurate read on this and other water quality trends,” she added.

But not all water quality trends were positive. More than 50 percent of the samples taken by citizen-scientists during Snapshot Day showed less-than-optimal dissolved oxygen levels. Dissolved oxygen is a measure of the amount of oxygen dissolved in water, and is used as an indicator of stream health because a certain amount of dissolved oxygen is necessary to support aquatic life, like mountain whitefish and Lahontan cutthroat trout.

“If dissolved oxygen levels drop too low, we start to see significant impacts on our native aquatic life,” said Zack Bradford, natural resources manager for the League to Save Lake Tahoe, “which is why the League’s work is critical.” The League is working to control the spread of aquatic invasive plants and inputs like Nitrogen and Phosphorus, which drive algal growth in Lake Tahoe. When algae and invasive plants die and decay, they consume oxygen, robbing it from our wildlife.

Snapshot Day has been held in the morning of the second Saturday of May for the past 18 years. It is a collaborative effort between the League to Save Lake Tahoe, the Nevada Division of Environmental Protection (NDEP), the Tahoe Water Suppliers Association (TWSA), and the Truckee River Watershed Council (TRWC). Additional agencies that assist include: The Pyramid Lake Paiute Tribe, the South Tahoe Public Utility District, the Lahontan Water Quality Control Water Board, and the Tahoe Regional Planning Agency (TRPA).

“We want to collect as much relevant data as possible each year and to do that we depend on dedicated volunteers. They are critical to the success of Snapshot Day,” said Darcie Goodman Collins, Ph.D., CEO of the League to Save Lake Tahoe. “This event is a great opportunity for our community to come together for one day to Keep Tahoe Blue.”