EcoStewards Program

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Nature Based Delta Solutions

Rachael Byrne

EcoStewards Conservation Technician

I’m a native Californian and have lived in the Bay Area for 15 years, but I didn’t know much about the Delta until I joined CCRCD’s EcoStewards crew a year ago. As a conservation technician I work to keep invasive plants at bay in restoration projects across the county. I enjoy working in the Delta because it is a dynamic environment, changing with the tides and visited by hundreds of thousands of migrating birds. It is also the heart of the state’s water supply. Often the needs of healthy habitat and quality drinking and irrigation water are at odds, making management of the Delta particularly challenging.

The Delta is formed by the confluence of California’s two largest rivers, the Sacramento and the San Joaquin, where these freshwater rivers flow into the Pacific Ocean through the San Francisco Bay. Because the Delta crosses multiple county lines, CCRCD works closely with both Yolo and Solano RCDs to restore habitat throughout the Delta. As one of the largest estuaries in the US, the Delta is an important habitat for fish, shorebirds, and other wildlife. All anadromous fish (those that migrate from freshwater where they hatch to the ocean where they spend most of their lives)from the Sacramento and San Joaquin rivers migrate through the Delta. The Delta is an important nursery for fish and serves as rearing habitat for juvenile fish. For example, Chinook salmon and steelhead depend on the Delta as rearing habitat while they migrate to the ocean. Fourteen species of fish found in the Delta are imperiled by dwindling population numbers, largely due to habitat loss (Cloern et al. 2011). Despite the huge loss of habitat in the Delta, the remaining wetlands serve as an important stop on the Pacific Flyway, where migrating birds can rest and forage.

In addition to wildlife habitat, the Delta is a major source of water for human use. Two-thirds of the state’s population(approximately 27 million people) depend on water from the Delta for some portion of their water supply. As a critical element in the state-scale water-conveyance system, the Delta also supplies irrigation for at least $27billion in agricultural production that provides 45% of the nation’s produce (Dettinger et al. 2015).

Before colonization the Delta was an expansive marsh. Today more than 90% of the original wetlands have been lost to urban development, conversion to agricultural fields, or degraded by pollution and exotic species introductions. The dramatic change in Delta channel geometry has altered seasonal flow, salinity, and sediment regimes to the detriment of native species. These changes are exacerbated by the effects of climate change. Sea level rise puts 270,000 people and $62 billion of development at risk of flooding (Cloern et al. 2011).

The risks of climate change and the Delta’s critical role as both habitat and water supply create a complex challenge for management. The San Francisco Estuary Institute proposes several mitigation strategies in the San Francisco Bay Shoreline Adaptation Atlas, and CCRCD is committed to implementing these strategies for the benefit of our county. The EcoStewards are involved in tidal marsh restoration projects that increase habitat while mitigating flood risk, and CCRCD works with farmers to integrate habitat on working lands.

The problems facing the Delta can be overwhelming, and competing needs make management complex. Over the past century humans have dramatically altered the landscape of the Delta to meet their needs while devastating critical habitat. Human-caused climate change continues to impact the Delta, putting both humans and wildlife at risk. But solutions are being developed and implemented now in the Delta. Some days I see more birds than people while working on habitat restoration sites in the Delta alongside legacy farms and housing developments. I am encouraged by how we are working towards a more sustainable future where human and wildlife needs are met.


Cloern, James E., etal. "Projected Evolution of California's San Francisco Bay-Delta-RiverSystem in a Century of Climate Change." PLoS ONE, vol. 6, no. 9, 21 Sept.2011, p. e24465. Gale Academic OneFile, 2 Oct. 2022.

Delta StewardshipCouncil, “The Delta Plan.” 2 Oct. 2022.

Dettinger, Michael,et al. “Western Water and Climate Change.” Ecological Applications, vol. 25,no. 8, 2015, pp. 2069–93. JSTOR, Accessed2 Oct. 2022.

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