Southern California Edison's 3.5-mile power line project slated to run through the Tierra Rejada Valley has raised the ire of the Center for Biological Diversity, which is calling the power company's proposed route the most environmentally destructive alternative yet.

While residents and city officials have argued with Edison for months about the aesthetic impact of its Presidential Substation project, the center has joined the fray over its potential impact on the local ecosystem.

The project threatens the existence of flora and fauna in the Tierra Rejada greenbelt, according to Jonathan Evans, staff attorney for the center, which is dedicated to fighting for environmental causes.

"A lot of investment has been put into creating wildlife movement and viability in this area," Evans said during a tour of the proposed project site earlier this month.

The tour was led by Chuck Cronin, cofounder of the citizens' group sTTop, or the Substation and Transmission Towers Opposition Project.

"To allow Southern California Edison to come in with this highly destructive route for the power line project is ridiculous," Evans said. "They have much better environmentally sensitive alternatives that they can choose that don't impact wildlife and don't impact communities to such an extent."

The project calls for the construction of a new substation and subtransmission line, which Edison says is needed to meet the increasing demand for electrical service in Simi, Thousand Oaks and adjacent unincorporated areas.

The substation would be located on the south side of Olsen Road in Thousand Oaks and the power lines would travel down Read and Sunset Valley roads.

"It's like putting a knife into a cake," said Cronin, who lives just off Read Road.

Initially, the route followed the property line of the Reagan Library, but public outcry pushed Edison to move the power lines to the lesspopulated Tierra Rejada Valley.

Edison filed an application with the Public Utilities Commission in December for a permit to construct, but the commission determined in February that the project must undergo a full environmental impact report.

The center filed a formal protest with the PUC against the project and submitted comments on what should be included in the EIR.

Of particular concern are three endangered species: Lyon's pentachaeta (a plant native to Southern California), the coastal California gnatcathcer (a grey songbird that only lives in coastal sage scrub and chaparral) and the Riverside fairy shrimp (a microscopic crustacean that lives in vernal pools).

Evans said Edison's proposed route will run through critical habitat for the gnatcatcher and will be adjacent to critical habitat for the Riverside fairy shrimp and Lyon's pentachaeta.

"These areas are critical for keeping these wildlife in existence for us and for future generations," Evans said. "If we don't do the minimum to protect their habitat, we could lose them."

The valley is also an important linkage for animals such as coyotes, rabbits and barn owls to move between the Santa Monica Mountains and Los Padres National Forest.

As part of the required mitigation for the 23 Freeway widening project, wildlife-proof fencing was installed along the highway rightofway to direct animals to crossing structures.

Three culverts under Highway 23 allow animals to pass safely. Evans said Edison's project would compromise the work that's been done to preserve the corridor.

"Obviously, this area is impacted already—there are roads, homes; it's already a constrained linkage," he said. "But by putting in additional power lines, it impacts the area more and you have a wildlife corridor that could suffer from a death of a thousand cuts."

Another concern is how the fuel modification and vegetation clearance will affect wildlife in the greenbelt. Cronin is worried that many of the mature trees lining Read Road will be removed, since Edison is required to clear a 5to10-foot swath around each pole.

In a report to the PUC regarding the center's protests, Edison states that once surveys of the area's sensitive species are complete it will propose appropriate mitigation measures to reduce impacts, though the company anticipates no "direct or indirect impacts" to the Lyon's pentachaeta or the Riverside fairy shrimp.

The report also states that vegetation removal associated with the subtransmission line will be limited to clearing around the poles and an access road. However, details on the fuel modification zone will be developed after the final engineering of the site is complete.

For more information on the project, visit www.sce.com/presidential.