The Mountains Recreation and Conservation Authority released a study Sept. 3 that spells out the details of an estimated $60-million wildlife passage across the 101 Freeway near Liberty Canyon Road in Agoura Hills, just five miles east of Thousand Oaks.
Commissioned and funded by the MRCA with a grant from the state’s Santa Monica Mountains Conservancy, the study, which was prepared by Caltrans, is the first step on the road toward building a wildlife passage across the busy eight-lane freeway.
The structure will allow animals to roam between the Simi Hills to the north and the Santa Monica Mountains to the south without having to use a concrete tunnel that currently runs underneath the freeway.
Scientists have identified Liberty Canyon as the best location for the crossing because of the large swaths of protected public land extending into the mountain ranges on either side of the freeway.
The study looked at a 165- foot wide by 200-foot long land bridge spanning the freeway with columns in the freeway median and retaining walls on either end.
The bridge, to be built about one-quarter mile north of the existing Liberty Canyon overpass, would be landscaped with native, drought-tolerant vegetation to provide a passage that resembles natural habitat.
Noise barriers would reduce traffic noise and block vehicle light at night in order to make the crossing more effective for wildlife. The new bridge would extend past the freeway and over Agoura Road.
Local representatives used the release of the study as an opportunity to throw their support behind the corridor.
“For over a decade, we have been working towards the goal of creating this wildlife passage in the Santa Monica Mountains,” said Richard Bloom, state Assembly member for Agoura Hills.
“Now, through a (study) that presents a viable, scientifically valid wildlife over-crossing, that goal is within sight. Public support has never been stronger; the ecological need has never been greater,” he said.
State Sen. Fran Pavley of Agoura Hills, who lives near the proposed wildlife corridor, is among those leading the charge for the bridge to be complete.
“It’s critically important to provide a safe crossing over the busy 101 Freeway for wildlife,” Pavley said. “A secure pathway also is essential to protect motorists, who could be killed or injured by collisions with animals,” she added.
National Park Service researchers have documented serious threats to the long-term viability of the mountain lion if a structure is not built. Twelve mountain lions have been struck and killed by vehicles in the park service study area since research began in 2002, including a male mountain lion that was hit on the freeway near Liberty Canyon Road in 2013.
The construction of the 101 Freeway divided the mountain lion habitat into isolated fragments, resulting in significant inbreeding, territorial fighting and low genetic diversity within the Santa Monica Mountains, experts say.
Bobcats, gray foxes, coyotes and mule deer also travel between the mountain ranges.
The details and environmental impact of extending the bridge over Agoura Road will be considered by the City of Agoura Hills through a series of public hearings and community workshops.
Caltrans will now turn to the next stage in the process, which is the preparation of an environmental document. Then it will address the most important question—who will pay for it.
“This report by Caltrans shows a crossing is not only feasible but affordable, and we look forward to working with state officials to make it a reality,” said Beth Pratt, the wildlife federation’s California chief.
