Progress Continues On Innovative Plan To Build 101 Overcrossing For Mountain Lions, Other Wildlife

May 16, 2018

Some new milestones have been reached in a cutting edge effort intended to help mountain lions and other wildlife safely cross Highway 101.

It’s an ambitious plan to create a freeway overpass between some wildlife corridors separated by eight lanes of freeway between Calabasas, and Agoura Hills.

Seth Riley is a Wildlife Ecologist with the Santa Monica Mountains National Recreation Area. Riley says aside from the danger of wildlife being struck and killed trying to cross the highway, the 101 serves as a man-made barrier for animals which perceive the threat and don’t try to cross. The result is the loss of genetic diversity as animals become isolated, and don’t move between areas.

Riley says they brought in experts who helped look at looked at seven different options for the crossing, examining everything from evidence of wildlife use to connectivity with habitat. The recommendation is for a crossing at West Liberty Canyon.  They also recommended an overcrossing instead of an undercrossing, saying a tunnel under the freeway would be prohibitively expensive.

It’s an ambitious effort, because the crossing would be about 160 feet wide, and covered with soil and plants to make it look like native habitat. It would have to cross eight lanes of freeway.

Riley says this report moves the project forward, but there are still a number of things which needed to be resolved. One of the biggest is money, with the price tag estimated at around $60 million dollars. If funding is raised planning completed, the project could potentially be built by 2021.

Riley says the project could set a new standard. While there are wildlife crossings over roadways around the world, he says there’s nothing on this scale.