Watching Snow Melt

Daniel McGlynn
April 11, 2016

Sierra-Net from CITRIS Media on Vimeo.

This article on Dr. Steven Glaser and soon-to-be Dr. Ziran Zhang was originally published on UC Berkeley's Engineering blog. It features UC Water investigators Steven Glaser and Roger Bales.

Ziran Zhang, a civil and environmental engineering Ph.D. candidate at Berkeley, is up ahead breaking trail. The movement of his snowshoes creates a crunch-drag, crunch-drag rhythm. It’s almost spring in the Sierra Nevada, and the bright sun gives the snow underfoot the consistency of quickly melting shaved ice. Zhang pauses every so often, looking through the evergreen branches of the dominant fir and cedar trees for tall silver posts he installed last summer, before there was three feet of snow on the ground.

There it is, he’ll say, and crunch-drag off in that direction. He’s followed by professor of civil and environmental engineering Steven Glaser, a systems expert and Zhang’s advisor. The two are here, at about 8,000 feet in elevation, in an alpine bowl above Caples Lake, on the outskirts of Kirkwood Ski Resort, south of Lake Tahoe, to check on a massive environmental monitoring array they have constructed out of hundreds of wireless sensors. The goal is to collect enough data to build accurate models of California’s precious water supply, which comes from the snowpack stored in the state’s high mountainous reaches, like this one. 

Some of Zhang’s posts hold a sensor station, equipped with a handful of measuring tools, while other poles have relay nodes to wirelessly transmit the information from each sensor array to a nearby base station. The base station compresses the data and in this case, because the site is so remote, beams it to a satellite and then back to Berkeley every 15 minutes.

Sierra Net
There are 14 Sierra Net sensor networks spread across the high elevation reaches 
of the America River headwaters.

The station in the lower right, marked as CAP, is the location of the Caples Lake sensor network. (Image courtesy Ziran Zhang). Having found the sensor station he was looking for, Zhang says, “This is just one of the 14 sites that we installed in the American River watershed.”

The American River headwaters run in three forks high in the mountains, braiding together behind Folsom Dam, east of Sacramento, altogether draining roughly 1,500 square miles. Once funneled through the dam, the American River continues on, meets up with the Sacramento River and eventually flows to the San Francisco Bay.

“Obviously, we can’t instrument all that area, so we’ve found representative physiographic regions and are looking at elevation, slope, aspect, vegetation and sometimes, the concavity of the surface,” Glaser says. “This site represents a much larger set of topography of the river basin.”

Continue reading at Berkeley Engineering