The Bay Delta

The Bay Delta bioregion encompasses the vast watershed system of the San Francisco Bay and Sacramento-San Joaquin River Delta, forming one of North America’s most ecologically significant and complex ecosystems. This diverse bioregion stretches from the coastal waters of the Bay, through wetlands and marshes, and South into the Central Valley and North into the Sacramento Valley, incorporating numerous tributaries that drain approximately 40% of California's land area.

The Bay Delta bioregion serves as a critical habitat for hundreds of species, including endangered salmon, Delta smelt, and migratory birds, while simultaneously supporting California's agricultural heartland and providing drinking water for over 25 million residents.

The region represents a dynamic intersection of freshwater and saltwater systems that has been dramatically altered by human development, water diversion projects, and agricultural expansion, creating ongoing tensions between ecological preservation, water rights, urban development, and farming interests that define the complex environmental politics of California.

Why The Bay Delta?

There are many ways to define bioregional boundaries, and bioregions exist across many scales. There is a valid question to be asked about the “right” context for a given outcome. Hence the importance of bioregional mapping.

The Bay Delta tidal estuary is a compelling scale to explore bioregional governance, not just because it is an intact and abundant watershed. The Bay Delta is also abundant in cultural diversity. The human partners here comprise a wonderful array of demographics, ethnicities, wordviews, interests and skill sets. Crucially, this Trust will also embrace the bioregion itself – the watersheds, along with the flora, fauna, and fungi living within – as a key partner and beneficiary.

The Bay Delta as a bioregion has historical precedents in regional and state planning. In 1991, California counties ratified the Coordinated Regional Strategy to Conserve Biological Diversity in which they agreed to adopt an adaptive approach in the development of bioregional strategies, and to establish Bioregional Councils. An initial map of California bioregions was drafted (right), with the intention of further defining boundaries with local stakeholders.