The Sacramento-San Joaquin Delta was once known as an expansive wetland landscape, formed after centuries of floods and natural growth. However, over the last 160 years, the Delta has rapidly declined and changed as modern land development has taken its toll. Now, a new study from the San Francisco Estuary Institute has issued a shocking conclusion: the Sacramento Delta can no longer be considered a delta.

In a report titled “A Delta Transformed,” funded by the California Department of Fish and Wildlife, the Institute compares the modern state of the 1,200-square mile waterway with its conditions since 1854. Their findings are shocking: the area has been radically transformed to allow for agricultural and urban development, including significant work to increase the region’s water supply. As a result, the most common habitat in the ecosystem has almost entirely disappeared, native wildlife are declining, and invasive species are prospering.

The Delta reportedly originally contained 10 different habitat types, including oak savannas, vegetated dunes, and grasslands. While the region’s grasslands and open water have increased since the Gold Rush era, the oak woodlands and dunes have essentially been eradicated. In 1854, there were 2,500 acres of dunes and 80 square miles of oak savannas; today, there are only four acres of dunes and no remaining oak woodlands. However, the greatest change in the Delta’s habitat is the disappearance of “freshwater emergent wetlands,” which refers to areas of standing water with plants rising above the surface. The study reports that there were nearly 750 square miles of this wetland feature in the mid-1800s, but years of draining, filling and dredging has left only 16.4 square miles remaining. This represents a 98% decline of a habitat type that was once one and a half times the size of Los Angeles. The report says it has also seen a similar disappearance of seasonal wetlands, such as vernal pools, wet meadows, and riparian forests.

While farming and urban development can be blamed for much of the waterway’s problems, another major issue is that the Sacramento Delta serves as an important component of California’s water transport system. While the river system once mixed seawater with runoff from the Sierra Nevada, Cascade and Coast Range mountains, it has since been adapted into a network of canals that move water from the north to farms in San Joaquin and a number of southern cities. This has a significant impact not just on the face of the area, but also its life: native species like salmon and other fish

can no longer travel downstream to the ocean, while the Delta’s famous annual floods no longer spread sediment packed with nutrients over the landscape.

In light of the report, the California Department of Fishing and Wildlife has said that it plans to use the information to help restore the Delta. The findings will apparently be used to determine which parts of the landscape could benefit from intervention and provide better habitats for native wildlife. But while this might solve the plight of the Delta’s salmon, the San Francisco Estuary Institute’s comments about the area suggest that the Delta will never return to its original condition.