"There! See him! Right there!" Jim Johnson is pointing to a riffle in a quick-flowing stream tiny enough for us to step across. All I see is what seems to be a stick, perhaps six inches long, in the rippling water. Suddenly, the "stick" flicks its tail and darts away. "See! A steelhead! That's what we've been able to do. We've brought back the steelhead to their natural waters."

With the clear, cold stream and the acrobatic game fish, we might be somewhere in a remote mountain setting. In fact, not far above us roar the trucks and minivans of a six-lane Interstate, and if it were not for the intervening trees we could see the nearby Hoover Tower of Stanford University and the office buildings of Silicon Valley. Johnson, an antiquities restorer by trade, is a part-time streamkeeper for this urbanized little rivulet and other tributaries of San Francisquito Creek, whose 43-square-mile watershed rises near the notorious San Andreas Fault and eventually empties into San Francisco Bay. "We" are some 300 college students, Silicon Valley engineers, teachers, housewives and Stanford faculty dedicated to monitoring and restoring it to what it was in the more benign days when the Ohlone Indians inhabited these parts. Thanks to the volunteers, says Debbie Mytels of the San Francisquito Creek Watershed Project, which coordinates the restoration campaign, "we're seeing steelhead where they haven't been seen for a hundred years."

Ariane Bertrand, assistant director of the Coyote Creek Riparian Station in San Jose, California, which trains the volunteers and oversees their efforts. A Thalweg is a basic step in understanding the physical characteristics of a stream, Ariane explains. It charts the deepest part of a river or channel throughout its course so that later observers can detect changes, track them to their source and, possibly, correct them. For instance, upstream construction can cause silting downstream. Mud slides can alter the creek's course.

I stand in the stream holding a telescoping surveyor's rod, calibrated in tenths of a foot. Volunteer Roberta Bischel squints at me through the 20-power lens of a survey level mounted on a tripod. "I can't see anything but his fingers," she complains. I move the offending fingers. "Four point six-two," she calls out to Diana Brumbaugh, a San Francisco State University graduate student, who notes the number in her log.

The figure, when subtracted from the instrument height, Diana explains, represents the elevation of the streambed at that location in relation to a bench mark whose elevation is known. "What's the composition of the bed?" she asks me. I look down at my feet. Having been briefed on the differences among silt, sand, gravel, cobble and boulder, I vote for a combination of gravel and small cobble. Diana makes another entry, meanwhile noting where the stream banks have eroded and the type of surrounding vegetation.

"If someone comes back to this spot next year and finds silt instead of cobble, they'll know to look for a problem upstream," Ariane says. She beckons me to move the rod some five yards farther along. Satisfied with my new location, she gestures to Roberta, who squints through the eyepiece; Diana makes more notes. We move the rod again, and slog slowly upstream until, after three hours, we have charted some 100 yards of waterway.

Largely through the efforts of the Environmental Protection Agency (EPA) and the Izaak Walton League's "Save Our Streams" program, waterway restoration is being conducted all across the country. Much of it is carried out by schoolchildren.

Because of its Mediterranean climate, however, California differs from other areas. When the rainy season ends in April, many streams simply disappear, not to reappear until November. Even the San Francisquito, which alternately bubbles and roars during winter storms, by late spring percolates into a gravel bed about five miles from its mouth.

The San Francisquito was chosen in 1993 for a project in "citizen monitoring," partly financed by a $50,000 grant from the EPA. "We chose it," says Michael Rigney, watershed program director at the riparian station, "because of the huge challenge. The watershed covers every kind of territory: forests, agriculture, pastureland, horsey suburbs, close-in suburbs, a college campus, shopping centers, industrial areas. The watershed straddles two counties and five major cities, plus Stanford University, a city in itself. There are two water utilities, two flood-control agencies and a total of 16 jurisdictions. You couldn't ask for more of a challenge than that."

Yes, you could, Debbie Mytels points out. In the six-month dry season, the streambed becomes a haven for the homeless, resulting in sanitary waste and refuse polluting and clogging the streams. Each winter, swiftly rising runoffs from Pacific storms sweep through the camps, forcing residents to evacuate in a hurry and abandon their possessions. Mattresses, sleeping bags, tarpaulins, plastic bags and clothing are swept downstream.

The sewage problem has been partly solved by the opening of a shelter in a Veterans Administration hospital. But the volunteers face other challenges. Plant-loving homeowners have introduced foreign plant specimens of all varieties, and some of these intruders have run wild. One of the most hardy and tenacious is an ornamental from South Africa, German ivy, which climbs up tree trunks and breaks off the branches, dragging them to the ground and destroying the stream's shade cover. If too much shade cover is lost along the San Francisquito, water temperatures could rise to a degree hostile to steelhead and the entire stream community.

Home gardeners also lace their lawns and flower beds with fertilizers and pesticides, some of which inevitably run off into streams. They drain the chlorinated water from their swimming pools into the creeks, oblivious to the harmful effects. Upstream in the foothills, horse manure from riding stables ends up in the water.

Public education has been a major thrust of the restoration effort. The group has developed a manual of native plants to be distributed to property owners, along with instructions for uprooting the interlopers. Other literature has described more benign fertilizers.

Education, however, is only half the battle. Thus, on a balmy September Sunday, we volunteers converge again along the San Francisquito and its tributaries for a cleanup day. We bypass the inhabited homeless encampments, but zero in on debris elsewhere in the creekbed. A couple of strong Silicon Valley engineers equipped with ropes haul abandoned shopping carts up the steep banks. Other volunteers fill plastic bags with trash, being careful not to disturb natural obstacles like fallen tree branches that could serve as shelter for fish life.

Our main target, however, is the ubiquitous German ivy on the banks, and it proves an implacable foe. Yanking the shallow-rooted stuff out of the ground isn't difficult, we find. The tough part is getting rid of it. You can't just pile it up and expect the plant to die; the ivy will quickly put down roots and thrive again. Vines and leaves have to be carefully crammed into garbage bags to be transported to the town sanitary landfill, and we are continually warned against dropping even a single branch, which could initiate a comeback.

There is still plenty of work ahead, Debbie Mytels tells me. Fish ladders on both Los Trancos and San Francisquito creeks are being restored. When the rains come again, trained volunteers will return to the streams to continue monitoring the changes in sediment, channel elevation and chemical content. "People drive over this creek every day and don't notice it," Debbie says. "We want to make it a community project, a part of local lives."

By Edwin Kiester, Jr.