Kings Canyon, Calif. ? The first wave of cold Kings River water slapped me hard in the face. Breathless, I was flung high in the air, my paddle far from the churning stream. A fraction of a second later, my raft hit the river — just in time for another nose dive into a swirling, clear green trough.

“It’s like being put through a washing machine,” said Marge Jensen, digging deep with her paddle as the river turned to foam on its rush out of the deepest canyon in North America.

Jensen, a volunteer with the environmental organization Friends of the River, joined me and five others for a 10-mile trip down the Kings, through one of about a dozen stretches of whitewater that have escaped dams in California and are suitable for commercial rafting.

The first rapids are the craziest, said Vince Strykers, a guide who has maneuvered down California rivers for 19 years. He’s part of an industry that draws thousands of visitors and their dollars to out-of-the way communities without disturbing the environment they come to see.

Water put to work

But like most Sierra Nevada rivers, the Kings never sees the ocean. Just a dozen miles downstream, the water we’re riding is put to work at Pine Flat Dam, a barrier 429 feet high with a hydroelectric plant.

Dams like this allow the state’s 36.1 million residents and the nation’s most fertile farm belt to get about a third of their water and one-quarter of their power from mountain rivers.

But demographers predict California’s population will balloon to 51.5 million by 2040, demanding an ever-greater share of the region’s natural resources. Kings River folk are fearful of plans like the one water agencies dusted off during the energy crisis of 2001, which would build another dam that would inundate the rapids.

Protecting the river

Paddlers ride the rapids of the Kings River in Kings Canyon National Park, Calif. Preserving this section of the Kings for the thousands of rafters drawn to the Sierra Nevada each year is one of the goals of a bill proposed in Congress.

The California Wild Heritage Act, introduced by Democratic Sen. Barbara Boxer two years ago, would protect this stretch of the Kings and 440 miles of still untamed rivers from dams and other developments that would alter the quality of the water.

Bob Ferguson, the owner of Zephyr Whitewater, hangs his hope of preserving the Kings on the bill. He remembers when the New Melones dam went up in 1982, holding back the waters of the Stanislaus River and flooding the narrow limestone cliffs where he’d spent years rafting.

“It was heartbreaking,” said Ferguson, whose outfit brings 3,000 to 4,000 rafters into the Sierra every year.

Energy needs

There are no plans to build Roger’s Crossing Dam across the Kings anytime soon. When the King’s River Conservation District last evaluated the possibility in the 1980s, the price tag — $600 million — made it too expensive. But district sees the 2001 energy shortage as evidence that it needs to protect its right to build.

Boxer’s bill “would take away our resource-planning ability in the future,” said district spokeswoman Cristel Tufenkjian. “The water and power needs in this area are only going up, and we need to be able to meet those needs.”

Local supervisors in rural counties like Tulare, Calaveras and El Dorado also oppose such protections, fearing it would slow development.

Similar opposition sprouted in Kernville, a small town on the banks of the Kern River, before a portion of the river’s north fork got the same “wild and scenic” designation in 1987.

“People thought it would be the economic ruin of the area, a case of elitist environmentalists coming in and taking away people’s private property rights,” said Bob Barnes, president of the Kern River Valley Chamber of Commerce.

Touting tourism

But Kernville is thriving today, thanks in large part to tourism. Businesses advertise their location on the banks of the “wild and scenic Kern river.” Rafting on the Kern has grown, and a new hotel opened up, Barnes said.

Rafting on the Kings already draws visitors to remote communities in the foothills. Tourists from other states extend tours of nearby Kings Canyon, Sequoia and Yosemite National Parks with rafting.

Variety of visitors

High school teacher Kathy Hooper drove four hours from Long Beach to celebrate her 50th birthday on the river with her friend Julia Hornby. Refrigeration mechanic Tim Valdez, who came with a rowdy group from the southern San Francisco Bay area, did a paddle high-five after careening through a threatening stretch.

The river flattens, and we rest for a few minutes. Smooth rocks shine on the river bottom. Dragonflies also take a break, settling briefly on our boat.

We gaze up at the cathedral-like walls of the canyon, which is a recovery area for peregrine falcons, and harbors bald eagles in the winter. Sycamores reach up by the bank.

Paddlers ride the Kings River in Kings Canyon National Park, Calif.

We’ve just passed Roger’s Crossing, Strykers tells us. All this would be underwater if a dam is built.

At the end of the day, some visitors nap in tents by the river. Others gather to chat and share a drink.

Hornby and Hooper, won over by what they’d seen, write letters to their representatives asking them to protect the river.