New Project Returning Former Quarry Site to Nature : Ventura River: Planned restoration of mining area is hailed as key step to regeneration of 20-mile waterway.

It had been nearly 85 years since a tiny songbird known as the least Bell’s vireo sang from the thickets of the Ventura River’s banks.

But last spring, after a sand and gravel quarry in the riverbed fell silent for the first time in decades, at least one and possibly two pairs of the endangered birds returned to nest along the river.

The nest at the edge of the mining site, along with a new restoration project to replant the quarry with native trees and plants, encourages biologists that wildlife will return as soon as human disruptions recede from the riverbed.

“California has already lost 95% of its wetlands habitat,” said Cathy R. Brown, U.S. Fish and Wildlife biologist. “In order for a species to recover, we have to make sure they have habitat.”

Brown credited Southern Pacific Milling Co., which mined the river for 25 years, and environmentalists at Friends of the Ventura River for creating a successful plan to restore a small portion of the river to a productive, natural area.

“Just closing down the operation and removing the equipment and reducing noise and dust and human activity has made the site much more attractive to wildlife,” said Mark Capelli, a biologist with Friends of the Ventura River.

The Ventura River, whose tributary headwaters are high in the backcountry of Los Padres National Forest, has long received pollution from farm runoff, storm drain discharge, treated sewage, encampments of homeless people and even an RV park along its path.

The planned restoration of the sand and gravel quarry is an important step in what biologists hope will lead to the regeneration of the 20-mile river.

“This is going to be one of the most significant steps taken toward restoration of the lower river,” Capelli said. “I think both the county (of Ventura) and SP Milling will be looking at it as a model.”

The 150-acre mining site, along a two-mile stretch of the Ventura River about a mile north of the Main Street bridge, was cleared for farming around the turn of the century, biologists said.

Vireos, once common in the area, were last seen nesting in 1909 in the Ventura River.

Since then, the river and its grassy banks and seasonally dry bed were kept clear of native brush. SP Milling took over the site from farmers in the early 1960s.

During peak production years of the 1960s, SP Milling used heavy machinery to scoop about 100 tons of rock and sand from the river bottom each year, said Bill Berger, vice president and general manager of SP Milling.

At one time, the company operated an asphalt plant at the site, combining crushed rock with heavy oil to produce blacktop for streets. The intense noise of rock crushing and the dust from trucks and other equipment drove wildlife away.

In 1990, SP Milling decided not to renew its permit for its riverbed operation because of the poor economy, a diminishing amount of rock and the prospect of getting bogged down with expensive environmental studies.

According to the conditions of its original permit issued in the early 1960s, SP Milling was required only to “fill up the gross holes and remove the equipment,” Ventura County planner Judith Ward said.

SP Milling was instead receptive to requests from the Friends of the Ventura River to do more to restore the riverbed site, Ward said. It took years to work out a consensus among several government agencies and environmentalists before a restoration plan was approved in June.

“It’s the first time something like this has been created in our area that everyone is happy with,” Ward said.

SP Milling’s Berger said company officials believe they have a responsibility to leave a mined area in its natural state as closely as possible.

“It’s really important that we view our impacts and the results of our business on the environment and the whole community,” Berger said.

The $150,000 restoration plan calls for replanting the two-mile stretch of the river with oaks, sycamores and cottonwoods along the banks and native willows and other shrubs at the riverbed.

The non-native bamboo in the area that clogs up the river’s flow will be removed. The company will also partly restore the natural contour of the riverbed, which had been dramatically altered by the mining operation. Last year’s heavy storms gave the plan a boost by depositing tons of sediment in the riverbed.

A river whose channel is deepened can make flood flows run faster and colder, hydrologists maintain. And that can alter conditions for native plants and animals and throw off the balance of the river’s ecosystem, said Capelli, considered an authority on the Ventura River by federal wildlife biologists.

Although Ventura County will monitor the site at least once a year during the six-year restoration project, Capelli said his environmental group will continue its vigil.

The restoration of the area will benefit other wildlife, including the endangered tidewater goby, which thrives in the Ventura River estuary, Capelli said.

“The restoration plan will substantially improve water quality in the estuary by reducing erosion and siltation,” he said. “The Ventura River is one of only 10 sites left in Southern California that supports the tidewater goby.”

Wildlife biologists are particularly excited about reopening a habitat for the least Bell’s vireo.

The vireo is still rare and only 20 pairs of the birds are in sites along the Santa Clara River. Once numbering in the thousands in California, the vireo has been driven to near extinction by loss of its habitat and by a parasitic bird that lays its eggs in vireo nests, biologists said.

The parasitic cowbird does not build its own nest, but leaves its eggs with nesting vireos, which nurture and feed the larger cowbird young.

“I have even seen a case where an adult vireo was feeding a young cowbird that was bigger than the adult,” said Jim Greaves, a wildlife biologist on contract with the California Department of Fish and Game to monitor vireo nesting in Ventura and Santa Barbara counties.

The cowbird young often hatch ahead of the vireo eggs, and then push the vireo eggs out of the nest.

Biologists are waging an intensive campaign to trap cowbirds, taking more than 2,000 adults from the Santa Clara River banks over the past three years.

The vireo population along the Santa Clara River has rebounded from 14 pairs in 1992 up to 20 pairs in 1993, primarily because of cowbird trapping, Greaves said. The siting of nests along the Ventura River is a hopeful sign that the vireo population will continue to grow, he said.

Greaves said the female vireo he saw nesting in the Ventura River was probably from the Santa Clara River, based on the color of her leg band. One of the males he spotted was from the San Luis Rey River in San Diego County.

“They are leapfrogging rivers, and that’s very important for genetic mixing to keep the gene pool healthy,” he said. “If the two young from the Ventura River survive to breed, they will be carrying genetic material that has not been mingled in the population for a long time.”

Capelli said the restoration effort will help provide at least a small area of habitat for the birds, which like to nest just above marshy ground in thickets alongside a river, and for other wildlife.

Nature will have the final say over the success of the project, Capelli said.

“If it doesn’t rain for three years, that could have a major effect,” he said. “Every restoration effort is, in a sense, an experiment.”