Santa Monica Bay National Estuary Program is one of the United States Environmental Protection Agency’s 28 National Estuary Programs, dedicated to protecting and restoring water quality and the ecological integrity of estuaries of national significance.

The Bay itself is the submerged portion of the Los Angeles Coastal Plain, bordered offshore by the Santa Monica Basin, on each end by the rocky headlands of Point Dume and the Palos Verdes Peninsula, and onshore by the Los Angeles Coastal Plain and the Santa Monica Mountains. Most Los Angeles beaches are along the coastline of Santa Monica Bay. The 414-square mile area of land that drains naturally to the Bay, known as the Bay watershed, is bordered on the north by the Santa Monica Mountains from the Ventura-Los Angeles County line to Griffith Park, extending south and west across the Los Angeles coastal plain to include the area east of Ballona Creek and north of Baldwin Hills. South of Ballona Creek, a narrow coastal strip between Playa del Rey and the Palos Verdes Peninsula forms the southern boundary of the watershed.

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Santa Monica Bay and its watershed encompass many types of habitats. These habitats deliver life’s necessities for the species that inhabit them, as well as essential ecosystem services that benefit humans, such as nutrient cycling, water purification, and flood control. The diverse ecosystems within the Santa Monica Bay watershed provide habitats for more than five thousand species of plants, fish, birds, mammals, and other wildlife. The Bay’s terrestrial and aquatic habitats include riparian woodlands and streams, coastal sage scrub, oak woodlands, coastal sand dunes, salt and brackish marshes, lagoons, and mudflats. Marine habitats include soft and hard bottom, pelagic ocean, sandy and rocky intertidal, kelp forests, seagrass beds, and submarine canyons.

The ability of the Bay and its watershed to support a rich and diverse ecosystem has also made it a highly desirable environment for human inhabitation. Prior to the late 1700s, the Bay’s watershed was primarily the province of Native American Chumash, Gabrielino/Tongva, and Fernandeño Tataviam peoples. SMBNEP recognizes it is on the Indigenous land of Gabrielino/Tongva, Chumash, and Fernandeño Tataviam who have lived and continue to live here. SMBNEP respectfully acknowledges Indigenous peoples as original and continued stewards of this land and its waterways and is grateful to carry out its work on their traditional lands.

The speed and magnitude of change that has occurred in the Bay watershed in less than 300 years is truly beyond any early settler’s imagination. Today, the metropolitan area surrounding the Santa Monica Bay is one of the world’s most populous urban areas. According to the 2021 U.S. Census, about 10 million people live in Los Angeles County and 3.8 million within the City of Los Angeles. The modern infrastructure and demands of this population have profound effects on the environment.

In addition to residents, the Los Angeles region receives over 45 million visitors per year. The Bay is home to world famous beaches, surf locations, and mountain trails. The diverse ecosystems of the Bay and its watershed offer an abundance of recreational, educational, wellness, and cultural opportunities that enhance quality of life for the resident and visitor. However, the footprint of this large human presence causes environmental degradation, leading to habitat loss and fragmentation, coastal erosion, water and air pollution, and water scarcity. Through a diversity of partners and efforts, the SMBNEP develops projects and programs that address these issues, reducing harm to the environment, protecting public health, supporting wildlife, and increasing coastal access and recreation. Many of these projects and programs produce multiple benefits including greater resilience to climate change, refuge for endangered and vulnerable species, and increasing local water availability.