By Matthew Chin

Southern California imports between 80 to 90 percent of its water from outside the metropolitan region. And much of it comes from the Sierra Nevada.

So to learn right at the source, UCLA students in the Civil and Environmental Engineering 157M hydrology of mountain watersheds class took a five-day field trip to Sagehen Creek Field Research Station, eight miles north of Truckee, Calif., in the heart of the Sierra Nevada.

“We depend heavily on the yearly snowpack in the Sierra Mountains which melts and flows into California reservoirs in the spring,” said Terri S. Hogue, a UCLA associate professor of civil and environmental engineering who teaches the class. “Understanding the amount and distribution of the snowpack, as well as the water content in the snow, or snow water equivalent, is critical for accurate spring forecasts of water supply for the state. Urban, agricultural and recreational users depend on these water supply forecasts for planning and management of this critical resource.”

The advanced class focuses on the study of catchment processes in snow-dominated and mountainous regions. Students measure and quantify snowpack properties, watershed fluxes, investigate geochemical properties of surface and groundwater systems, classify mountain streams and evaluate flooding potential.

The field trip to Sagehen has been a part of the class since Hogue started teaching it in 2006. The goals are to understand snow-dominated watershed processes, familiarize students with the observational data and uncertainties in hydrologic design, and utilize a range of equipment to gather that data. Students also connect to where much of Southern California’s water comes from.

This year, California had a big year for snow, with the statewide snowpack at 144 percent over average. The class of 32 students faced tough late winter conditions, despite the late April stay at the mountain research station. There was five feet of snow at the station, and more than 20 feet at higher elevations. And it rained or snowed almost every day the class was there. But the weather also made the field trip memorable.

“It was gorgeous, but it definitely made the process more difficult,” said Carolyn Chou, who graduated in June and is now studying hydrology at Princeton University. “Hiking in fresh snow every day was slower than if we were hiking on hard pack, and taking measurements in freezing conditions was definitely more difficult than if temperatures had been warmer.”

“We had studied the conditions before by looking at data recorded by sensors and weather towers in the watershed, so we pretty much knew what we were getting ourselves into,” said Sara Miller, a senior finishing her last classes this fall. “That being said, snow shoes are difficult to walk in and gloves make handing equipment tricky. It was definitely more of an adventure to have to keep working no matter how cold it was or how much it was snowing.”

Hogue and the graduate teaching assistants made adjustments to the planned measurements depending on the conditions. This included taking snowpit measurements, which quantifies how much water is in the snow, at a lower altitude.

“Actually performing the hydrologic field measurements added another dimension to what we learn in the classroom,” said Brandon Hale, a graduate student enrolled in the class.  “All hydrology classes use data that is collected in the field, but we never experience how that data is collected. Performing the data collection ourselves allowed us to see the advantages/disadvantages, errors, and accuracy associated with various methods.”

For these UCLA students, this course could be the first step in a career in water resources engineering, a field where there is a large variety of opportunities.

“Climate change, as well as expanding urban and agricultural demand, will require highly skilled, interdisciplinary engineers,” Hogue said. “They will work to develop innovative water technologies, improve our predictive capabilities, maintain the quality of existing resources, and optimize management of the state’s water supplies.”

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Main Image: Students on the trip. Photo by Terri S. Hogue.