El Niño threatens deadline for $114 million wildlife overpass in Southern California

A $114 million wildlife crossing over the 101 Freeway in Agoura Hills is on track to finish by Dec 2, provided a severe El Niño storm does not intervene. The structure already includes a concrete bridge across ten lanes and a vegetated deck with about 6,000 native plants, and a recent overpass over Agoura Road has been completed. The remaining work involves depositing millions of cubic feet of soil to create a continuous corridor linking the freeway, nearby road and northern habitats, a process that can be stalled by rain because the local clay-silt soil becomes dangerously slick and hampers compaction.

Beth Pratt, who heads the Wildlife Crossing Fund, and lead landscape architect Robert Rock both stressed the weather risk, recalling a 2022-23 rain event that delayed earlier work. Despite attacks from right-wing commentators and a $114 million price tag, the project is defended as essential for the threatened mountain lion population, which suffers from high rates of inbreeding; genetic models predict near-certain extinction within 50 years without new gene flow. Early wildlife monitoring has already recorded coyotes, deer and a female lion with cubs near the crossing, and the corridor is expected to allow future generations of lions to move between the Santa Monica and Simi Hills, boosting genetic diversity.