Waste Management El Sobrante Landfill and Wildlife Preserve

Corona, California, United States

Certified Gold through 2023

Project Name
Project Type
Many-Stemmed Dudleya
Riparian habitat
Wetlands & Water Bodies
Burrowing Owl
California Gnatcatcher
Stephens' kangaroo rat
Boy & Girl Scout Projects
Awareness & Community Engagement
Summer Day Camp
Awareness & Community Engagement
Stephens Kangaroo Rat
Species of Concern
The El Sobrante Landfill is located in Riverside County, to the east of the Temescal Valley in Southern California. The landfill, which is 468 acres, has the disposal capacity of 10 million tons. Surrounding the landfill is 680 acres of land that has been placed into permanent habitat conservation. Upon closure, the landfill will be added to the El Sobrante Wildlife Preserve and will total over 1,300 acres of protected habitat. In preparation for this, El Sobrante manages several unique habitats on site, as well as over 31 plant and animal species that are of conservation importance through an Habitat Conservation Plan.
Practices and Impacts
  • Many-stemmed dudleya are plant species of concern in California. Participating in a Habitat Conservation Plan, the team has a goal of mitigating dudleya loss due to landfill expansion. To do this, the team transplants impacted dudleya in a 15 acre mitigation site. To date, more than 22,000 dudleya have been relocated to restoration plots. 
  • Since 2015, the team has been managing 7.6 acres of riparian restoration habitat with the ultimate goal of replacing invasive, non-native weed species with native riparian species. In 2018 and 2019, the team noticed that survival rates for recently planted vegetation were low (~50%) and installed an irrigation drip. Because of this, the survival rate jumped to 88% in 2020.
  • The burrowing owl is a species that is declining throughout California. With the goal of creating a colony of burrowing owls on site, the team installed artificial burrows to provide sheltering and nesting opportunities for the species. Since installation, the team has observed one nesting pair and three individuals wintering at El Sobrante.
  • The team also monitors a second species of bird, the California gnatcatcher. This species is found in coastal sage scrub, relying on the habitat for nesting, foraging and shelter. The team's goal is to support 11 pairs of gnatcatchers in the Preserve and 4 pairs on restored landfill. In 2018 and 2019, 19 California gnatcatcher territories were recorded, while in 2020, 24 territories were noted. 
  • Stephens' kangaroo rat (SKR) is a species of concern in California as its habitat is threated by tall, invasive grasses and disturbances from vehicles. To combat these threats, the team fulfills a 1:1 mitigation of SKR habitat, resulting in 183 acres of maintained habitat. This land is actively improved though targeted weeding and debris removal. The team monitors the species with surveys of active burrows, scat, and trails.
  • Each year the team hosts a variety of events with their local boy scout and girl scout troops with the goal of providing educational opportunities for the children to learn about endangered species and conservation. The most recent activities include cactus and riparian plantings as well as installing six underground burrows for a rare burrowing owl. This is an ongoing project that started in 2009, and has supported over 300 scouts in earning merit badges as a result of the work they completed at El Sobrante Landfill and Wildlife Preserve. 
  • In 2019, the team hosted Summer Day Camp for local children with the goal of providing outdoor, hands-on learning opportunities to the community. Taking place throughout the El Sobrante Wildlife Preserve, children learn about the variety of wildlife and habitat projects occurring at the landfill, including how endangered species such as Stephens' kangaroo rat and the California gnatcatcher use the variety of unique habitats on site.