As students sipped samples from Dixie cups, their comments didn’t quite have the ring of a sophisticated wine tasting.
“I guess I’d brush my teeth in it.”
“It has kind of a weird aftertaste, like a swimming pool.”
“Yow—toss it.”
The 10 undergraduates enrolled in Geophysics 104: The Water Course were tasting water from around the world—and, as it turned out, from their own hometowns. Junior Molly Meyer, for example, should’ve known what was in bottle No. 13. When the wrapping was removed, the flask was revealed to have come from her father, along with a carefully hand-lettered label: “Indiana Water Company tap water. Collectors Vintage. Rare. Aged for enjoyment since 2/15/03.”
The point of the exercise? To experience how geological factors like “residence time” control the chemistry, and therefore the taste, of water. Rainwater that moves rapidly through rivers and lakes, for example, has a very different taste from water trapped in the ground for hundreds or thousands of years. “The longer the rock and water react, the more the chemistry of the water is going to be changed by the chemistry of the rock,” says geophysics professor Rosemary Knight.
The hands-down winner in Knight’s class this year was bottled water from Fiji’s volcanic highlands, voted both “soft” and “refreshing.” Runners-up included vapor-distilled water with added electrolytes, groundwater from the granitic Sierra and glacier water from Canada. The nastiest? Las Vegas tap water.
Knight, PhD ’85, a specialist in geophysical imaging, designed the course to attract undergraduates who might not otherwise be inclined to take a class in geophysics. “And how do you get an English major to perk up and pay attention when you’re talking about satellite measurements or reflected infrared radiation?” she asks. “By making that information relevant to something that’s important to her, which is where her water comes from.”
In fact, that’s the goal for the quarter: plotting the course of hometown water, from precipitation to tap. After learning how to analyze data from the U.S. Geological Survey and the Environmental Protection Agency, students zero in on the water sources for their localities, including Los Angeles, Mexico City, Tulsa, New Orleans and San Jose. They determine what percentage of land covering in their hometowns is forest or pavement, then figure out how much precipitation winds up in the ground and what it all means in terms of domestic, agricultural and industrial water use. The end product? Information posted on the class website that can be downloaded by, say, junior Danielle Murray’s local water district in Waterbury, Vt.
Although there’s no math requirement for the course, students tend to have strong backgrounds in calculus and linear algebra, which come in handy as they construct models of water storage and evapotranspiration. Learning to quantify a system as complicated as the hydrologic cycle is “incredibly empowering,” Knight says. “It makes them realize that math does work, and they learn that they can sit down, do an analysis and actually be in a position to say something quantitative about long-term water supply in their hometowns.”
Sophomore Kenny Dixon saw immediate real-world applications from his study of the Raymond Basin Aquifer in Pasadena, Calif., which relies heavily on imported water. Before he took Knight’s course, he hadn’t heard about activists’ proposal to tear out concrete channels that alter the natural flow of the Arroyo Seco River. But Dixon now understands that it can be done without causing floods and that the resulting river and creek beds would provide habitat for several endangered species. “I thought to myself, ‘That’s the kind of work I’d eventually like to do,’” he says.
Research for term papers takes students farther afield. Senior Annie Kellough studied China’s Three Gorges Project, and sophomore Kelly Grijalva learned about desalination in Saudi Arabia and the overall scarcity of water in the Middle East. Meyer, who helped install a gray-water toilet system at a Buddhist monastery near Carmel, Calif., last summer, says she’d like to find a job where she could “help the environment and other people.”
That’s what Knight loves to hear. “They’re going to do all sorts of amazing things in their lives,” she says. “Ideally, you would like them to leave Stanford with a higher level of what I call geoliteracy—an understanding of how the Earth works.”
