Three years ago, when Mark Murphy first saw the pristine walls of Thousand Oaks' La Barranca covered with graffiti and other signs of urban life, he was angry.
The isolation that preserved the oak-studded canyon for many years is now destroying it, he said. Unlike 1,300-acre Wildwood Regional Park north of the canyon, which is preserved by the city, La Barranca is largely ignored, he said.
"Here is a refuge of nature that is being surrounded and swallowed by the city," said Murphy, a Newbury Park resident. "It's been doing its best as an ecosystem to survive."
Murphy, a 39-year-old designer at Design Works, has launched a campaign to clean up the canyon for good. He has asked the city of Thousand Oaks, which owns some parts of the canyon, to take it under its wing and install a trail system, signs, bridges and foot paths.
He has also advocated the construction of storm drains and the burial of an unsightly sewer pipeline that runs along the canyon walls.
"If people are aware that this is a valuable community asset, then we'll have more people come through here cleaning it up," he said.
La Barranca--Spanish for canyon--is a three-mile-long gorge that runs north from Hillcrest Drive to the city's sewage treatment plant. The canyon, part of the Arroyo Conejo, is a 10-minute hike from the closest residential street. It is bordered on both sides by housing tracts--Lynn Ranch and the planned Shapell housing project. While city officials agree that the canyon should be preserved, they are reluctant to establish more trails.
"It's a nature preserve area that we really don't anticipate any improvements in as far as trail access," said Doug Nickels, the city's open-space planner. "We just want to leave it in its natural state."
For years, the sheer canyon walls that lured adventurous hikers prevented work crews from venturing in with sandblasting equipment, he said. Rangers have been unable to patrol the area regularly to prevent weekend visitors from illegally camping in the canyon.
A city study conducted in 1977 called it "the Grand Canyon of the Conejo," said Rorie Skei, chairwoman of the Conejo Open Space Conservation Agency.
The canyon was abused because it did not belong to any one private owner and was not under the jurisdiction of one public agency, Skei said. Although there is considerable interest from the conservation agency in Murphy's plan, Skei said a trail system throughout the canyon bottom would be hazardous for hikers.
"It's precipitous and quite dangerous," she said.
Once inside the gorge, sandstone walls rise 300 feet in some spots, and majestic waterfalls hide caves that have been carved by years of falling water. Rushes, willows and cattails rise from fertile marshland and then give way to mighty oaks farther on.
The area has a rich history as well. The creek once supplied ancient tribes of Chumash Indians, and artifacts have been found there, Murphy said.
The canyon is also home to wildlife. Murphy said he has seen deer, coyote and ducks there. Even non-native trees, washed into the creek from domestic gardens, have sprouted and taken root.
But the Conejo Valley's Grand Canyon is also its main drainage ditch and trash dump, even attracting some toxic industrial pollutants, a county environmental official said.
It has become the resting place of at least four rusting vehicles. An upside-down Chevrolet Camaro lies in one spot, and the bumper of an old Ford Pinto is half-submerged in water.
When Murphy first stumbled on the canyon, he said, it was covered with plastic and glass bottles, aluminum cans and fast-food containers.
"This was a disaster when we first came through," he said.
Murphy said the canyon must be preserved before the first houses are built in the Shapell development and more household waste ends up in the creek.
Across the state, many creek beds like La Barranca face pollution from encroaching development, said Earl Cummings, manager of a state Department of Water Resources program that is helping to preserve 60 streams in California.
"Every time you get a rainfall, the crankcase oil and antifreeze and lawn clippings that people have dumped wash into the creek and cause water-quality problems," said Cummings, whose program doles out about $1 million a year to help local groups restore streams.
In his search for canyon benefactors, Murphy contacted local environmental groups, as well as the Urban Creeks Council, a Berkeley-based volunteer organization that has helped community groups restore urban waterways.
Suburban neighborhoods are starting to look differently at local streams and canyons that have been destroyed or entombed in flood-control channels, said Bruce Van Allen, a director of the Urban Creeks Council.
"Most people think the environment is out in the Sierra or Alaska or in the desert," Van Allen said. "It's a change in mind-set to look at environmental features within the city."
Murphy's call for volunteers has already lured groups of Thousand Oaks environmentalists who have hiked into La Barranca. They have taken a low-tech approach to restoration, using burlap bags to move trash out of the creek.
Murphy also has experimented with nontoxic solvents that would cleanse the graffiti from the canyon walls. He would like to rig a portable sandblaster that could be carried in.
But more than sandblasting needs to be done at La Barranca, Murphy said. He hopes to establish a docent program that would lead guided tours through the canyon and a fund that would go toward a permanent cleanup program.
On a recent tour of the canyon, Murphy plucked a plastic bottle out of the water and shook his head, clearly irritated.
"How many towns have an urban wilderness?" Murphy said. "It's going to be a trashy canyon full of stinking water if we don't take care of it."