And for two weeks every summer, Agua University students headed out on a camping tour of urban California's water sources: Yosemite, Owens Valley, the California Delta. Once, while visiting with the Winnemem Wintu Tribe at Mount Shasta, one of the kids found a discarded plastic water bottle whose contents had been bottled where they stood. "That had a big impact on us," says Villareal, "because we had just learned that water is sacred for (the tribe). And because so much of their water is used for bottled water, they can't use it the way they used to."

"It was," Luna adds, "a profound spiritual moment."

A handful of Agua University's 118 graduates have gone on to pursue careers they once would have considered off-limits. Villareal, who says he had "no purpose" in high school before the program, now studies civil engineering at Los Angeles Trade Tech College, with hopes of "relating my studies to the environment." Luna's students also saw career possibilities open up as they listened to certain guest speakers. Once, for instance, some divers from the local environmental group Baykeeper came to talk about kelp restoration. "They came in with all this scuba gear," Luna remembers, "and showed them the basics of diving, which they needed to do if they wanted to work on the project. They saw that this person had a job, and it was a fun job. And they started to ask, 'What do I need to do to become scuba certified? Can I save $500 in my current job so I can do that?' "

Luna went about looking for other jobs that might be within the reach of young people who might not be destined for college. Water-quality testing filled an obvious need, but Luna lacked the laboratory and equipment to produce rigorous data for state or federal agencies. Last winter, however, he secured a $65,000 grant from Metabolic Studios, a philanthropic organization devoted to science-based restoration, and used the money to launch the Urban Stream Corps in partnership with the Los Angeles Conservation Corps, turning out trained water analysts to work with the state and county.

The grant allowed Luna to set up a sophisticated laboratory, vetted and approved by the state water board. It also allowed him to pay his recruits for three months of training, during which they collected data at more than 30 sites.

The work was not for everybody. Last May, Luna started out with nine students culled from the Conservation Corps, ranging in age from 18 to 22. All of them came from "tough neighborhoods," and none had been to college. By the time the program ended in July, he was down to four.

"The work was challenging," says Anthony Jackson, 21, one of those four. Collecting water in an urban environment sometimes involves dropping a bucket from a 50-foot bridge and hauling it up; then you have to carefully measure the ratio of liquid to chemical. "You have to be really precise; you have to take it step by step to get the correct results," Jackson says. "One little thing can mess up the whole test."

But Jackson found the work fascinating enough to pursue as at least an interim career. "For me, it's about getting out and doing something that matters in the world," he says. The training also transformed him: "I keep trying to get my dad to stop washing off the driveway with a hose," he says. "I tell him, 'All that water runs into the ocean.' "

Luna himself has hired an Urban Stream Corps graduate, 20-year-old Edgar del Campo, to work part-time at his own public landscape-design firm, Dake-Luna Consultants. And Luna is in the process of recruiting a new Urban Stream Corps, this time to gather data on dry-weather runoff from the foothills of the San Gabriel Mountains. In the meantime, Agua University continues, as does a more personal project of Luna's: Passing Grandmother Hercilia's lessons down to his 16-month-old daughter, Olivia. "She's been visiting the Los Angeles River since she was 4 months old," Luna says. And she already knows how much it matters. "Her first words were 'daddy' and 'mama'," Luna says. "But her third was agua."