The Nature Conservancy. Protecting nature. Preserving life.™

Sandhill cranes in the Delta. Photo © Ramona Swenson / The Nature Conservancy

Whether they know it or not, almost all Californians rely upon the Sacramento–San Joaquin Delta. In fact, it supplies one of our most vital and precious natural resources: freshwater.

The 700,000-acre Delta is the heart of the largest estuary on the West Coast of the Americas and home to 750 distinct species of plants and animals, some found nowhere else on Earth. It also sustains farmland that produces about 45 percent of the nation’s fruits and vegetables.

Each year streamflow originating in the Sierra Nevada and the coastal and southern Cascade ranges is transported throughout central and southern California, comprising one of the world’s largest water-delivery systems. This maze of tributaries, sloughs and islands, located east of the San Francisco Bay Area, stretches nearly 50 miles from Sacramento south to Tracy.

On the Verge of Collapse

The Delta is an ecosystem on the verge of collapse due to invasive species, pollution and the destruction of most of the area’s wetland and river habitat. Existing water-supply operations have also had profound impacts on the Delta. They have transformed the estuary into what is now essentially a freshwater lake and have reversed the natural direction of the rivers flowing out of the Delta. As a result of these and other issues, several native species, such as the Delta smelt, are on the brink of extinction.

Many of the Delta’s earthen levees are just one earthquake or major flood away from collapse. In addition to the environmental impacts of a natural disaster, such an event would disrupt the water supply for millions of Californians for months or years and could have a catastrophic impact on our economy.

Climate change is bringing additional pressures to the Delta. Sea-level rise is pushing more saltwater into the Delta and adding pressure to its fragile levees. Less snow and more rain in the Sierra Nevada will increase the winter river flow and further strain the levees as flooding becomes more intense.

Working Against the Clock

The Nature Conservancy has protected and restored nearly 25,000 acres of wildlife habitat in the Delta and manages a wildlife-friendly farm operation next to the Cosumnes and Mokelumne rivers. The Conservancy has also been deeply engaged in Delta planning efforts and studies, including major efforts like the Bay Delta Conservation Plan and Delta Vision — all of which seek solutions to the Delta crisis as quickly as possible.

Additionally, Conservancy scientists recently completed an independent study of the Delta using our Conservation by Design process. Our findings led us to conclude that the only way to save this beautiful and unique region is to restore significant portions of habitat as well as the natural water-flow conditions under which native Delta species evolved and thrive.

After careful analysis, The Nature Conservancy has come to the conclusion that we need a new conveyance system to move water through the state and restore natural water flows in the Delta.

Moving Past the Debate

The concept of an alternate water conveyance system in the Delta is not new and was quite controversial when it was first proposed in the early 1980s. However, today there is broad recognition that it would serve dual purposes to restore the Delta ecosystem and provide a reliable water supply to other parts of California.

Ultimately, advances in water conservation and technology will enable many regions in California to become largely self-sufficient for water, but this will not occur within the timeframe left to save the Delta.

Verging on a Solution

California’s leaders recognize the urgency of this situation, and have taken an historic step towards restoring the Delta with the passage of a landmark water package. It will provide the most comprehensive water reform in the State's history and will improve the health of the Delta and reliability of California’s water supply once and for all.