WATERFORD -- River guide Carlos Leonzo had warnings for the rafters about to set off down the Tuolumne.
Look out for branches submerged by the high flows this spring. Point your feet downstream if you get tossed. And beware of a swan that likes to fly close to the water.
"He's very territorial," Leonzo said. "So far, I have not been attacked, so we'll see."
Talking about the life of the river is the whole point of Paddle to the Sea, a monthlong effort to raise awareness about the Tuolumne and downstream waters.
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The 241-mile event, organized by the Tuolumne River Trust, started May 7 with whitewater rafting near Groveland. It reached Modesto on Saturday and will end June 5 with sea kayaks in San Francisco Bay.
Participants can do one or more legs. They pay a fee and also must raise at least $50 for the trust's efforts on behalf of fish, wildlife and recreation.
The Bee climbed aboard for last Monday's six-mile journey from Waterford to Hughson. Light rain fell much of the way on a group that had expected to be slathered in sunscreen.
This is not one of the more renowned stretches of the river, which starts at about 13,000 feet in
Yosemite National Park and flows through the Grand Canyon of the Tuolumne before hitting its first wall at Hetch Hetchy Reservoir.
Nor is it a churning chute of whitewater like the stretch just above Don Pedro Reservoir. But the river does run fairly high these days in the Waterford-to-Hughson stretch, thanks to steady storms and releases from Don Pedro.
The flows could benefit salmon, a key concern for the trust, said Jesse Roseman, the group's Central Valley program director, who was along for the trip.
About 40,000 of the fish spawned on the Tuolumne in 1985, according to the California Department of Fish and Game. It counted 455 in 2008.
This time of year, juveniles that hatched in the fall are trying to make their way down the Tuolumne, through the Sacramento-San Joaquin Delta and on out to the Pacific Ocean.
Roseman said even bigger Tuolumne flows are needed at times to scour out the channel and build up the gravel where salmon lay their eggs upon returning from the ocean.
Much will depend on the upcoming federal relicensing of Don Pedro, which supplies the Modesto and Turlock irrigation districts. The seven-year process will deal mainly with how much water to release for fish.
"We're going to have to be involved as we put together the studies and figure out what's really going to bring the salmon back," Roseman said.
The MID and TID are leery of increased releases but have helped fund other efforts on behalf of salmon, such as depositing clean gravel in the riverbed and restoring native vegetation along it.
The districts also point to threats to the fish in the delta and beyond, including predation by non-native striped bass and pollution from city sewage systems.
"There are things that we can do in our riv- er operations," said Walter Ward, MID's assistant general manager for water operations, "but once the fish get out to the San Joaquin and the delta and bay and ultimately the ocean, there are things beyond our ability."
Roseman noted the damage done by gravel mining, which reshaped the Tuolumne channel and left deep pools that can harbor predators of salmon.
"And then the river becomes a lake and the fish go through the gravel ponds and have to run the gauntlet of bass and other large fish that see a tasty treat coming," he said.
The districts release water from Don Pedro under a 1995 agreement aimed at protecting fish. This has reduced irrigation supplies, but not nearly as much so as in the parts of the San Joaquin Valley that rely on the massive delta pumps.
The MID and TID benefit from senior water rights, secured soon after they were founded in 1887.
More than 120 years later, the Tuolumne still nourishes the local economy. The land it waters accounted for most of the estimated $2.47 billion in gross income to Stanislaus County farmers in 2008. Billions more were earned by people who supply the farmers or process the crops.
Hydroelectric plants on the river are the cheapest source for power customers in the MID and TID, although the share is much smaller than in decades past.
"We are extremely fortunate to have the Tuolumne River, and we are extremely fortunate to have Don Pe- dro," said Tom Orvis, governmental affairs director for the Stanislaus County Farm Bureau. "You have to think about the foresight of MID and TID. They were way ahead of their time."
The people paddling the river Monday were well aware of the competing interests and the crucial decisions to come. But about an hour into the three-hour trip, something more urgent arose.
"Is this the dive-bombing swan?" one of the rafters asked as the big bird flew by, just as the guide had warned.
"The thing's like a 747!" another rafter said.
The swan had made its point, and the rafts floated on, finally pulling up at the fishing boat ramp just east of Geer Road.
For most of the participants, it was the only leg of Paddle to the Sea that they would do. Brian Coggan of Sausalito plans to cover the whole route, just as he did by kayak on the Mississippi River last year.
"I love seeing rivers in their entirety, not just the beautiful sections, the exciting sections, but really the whole river," he said. "It's like knowing a person for their whole life rather than just seeing them for a day."
Paddle to the Sea will continue this week with canoes and kayaks on the lower Tuolumne and San Joaquin rivers. A delta yacht cruise and other legs will follow in early June. More information is at 888-994-3394 or www.tuolumne.org.
Bee staff writer John Holland can be reached at firstname.lastname@example.org or 578-2385.