Bay-Delta: An Introduction

This is the 1st in a series on the crisis facing the Sacramento-San Joaquin River Delta. Click here for a list of all posts in the series.

Bradford Island, western Delta; courtesy of Sac Bee.

The Sacramento-San Joaquin River Delta (referred to here as simply “the Delta”) is, in a nutshell, California’s most important water resource. The Delta occupies a 1,150-square mile area located just to the east of the San Francisco Bay Area and west of the Central Valley, at the confluence of the south-flowing Sacramento River and the north-flowing San Joaquin River, which then flow to Suisin Bay, Carquinez Strait, San Pablo Bay, and thence to San Francisco Bay and the Pacific Ocean. Altogether, these assorted bodies of water comprise the San Francisco Bay-Delta Estuary, the West Coast’s largest estuary, with a watershed that encompasses about 40-45% of California’s land area. The ecosystem of the Delta is home to some 750 species of plants, fish, and other wildlife. The Delta is also the hub of California’s water infrastructure: about 22-25 million Californians and 4.5 million square miles of farmland rely on diversions from the Delta for water, supporting the agricultural and urban areas that provide for the state’s well-being and fuel its economy.

Although Californians have relied for decades on the Delta as a static source of freshwater, the Delta was historically a great tidal marsh whose salinity (salt concentration) was dynamic — varying with the tides, with some parts fresh and other parts brackish. Beginning with the Gold Rush in 1848, there was an influx of thousands of settlers into California, and many of them decided to pursue a fortune based on agriculture, rather than gold. The Delta was regarded as a fertile region whose agricultural output could support the state’s burgeoning population. Congress passed the Swamplands Act of 1850, in which control of federal swamplands around the nation were turned over to states, and title was then transferred to individual private parties who would drain the swampland and reclaim it for productive use. The Delta was included among the lands that were handed over. Throughout the latter half of the 19th century and into the early 20th century, Delta settlers fought a decades-long struggle against both mining debris dispatched upstream, and the vicious floods that swept through the Sacramento Valley. But the Delta, though not wholly “conquered” even now, was eventually drained and converted into a rich agricultural resource. It is now a patchwork quilt of about seventy islands reclaimed as farmland, separated by some 700 miles of rivers and other waterways, and protected by over 1,100 miles of levees. Although most deltas fan out to a triangular shape near to where the river flows into a larger body of water, this Delta is one of few throughout the world that are inverted: the wide end is in the inland Central Valley, and the Sacramento and San Joaquin Rivers flow into a narrow mouth going out to sea.

The Delta and the East Bay; courtesy of NASA.

Farmers during the early decades of Delta reclamation were beleaguered by considerable sedimentary debris (the “tailings”) that moved downriver from the upstream hydraulic mines where it was originally discharged. The debris choked the Delta’s waterways and harmed its agricultural production. According to an estimate from the Public Policy Institute of California, more than 800 million cubic yards of debris from the mines made its way through the Delta between 1860 and 1914, an amount that could fill 10,000 football fields sixteen yards deep. Agricultural and mining interests came to a head in the 1880s, when a series of decisions in California courts attempted to halt the practice of using the river as a dumpster for tailings. The decisions were largely ignored — until 1884, when the Ninth Circuit delivered a definitive ruling in the landmark case Woodruff v. North Bloomfield Gravel Mining Company. The ruling came from Lorenzo Sawyer, who himself was first drawn to California by the Gold Rush. Nonetheless, Sawyer called for the end of dumping tailings into the river, and operations at hydraulic mines throughout California ground to a halt. In 1893, Congress passed the Caminetti Act, which created the California Debris Commission, an agency consisting of three officers from the U.S. Army Corps of Engineers. The California Debris Commission permitted only certain hydraulic mines to operate, namely, those that used dams to prevent debris from flowing downstream. It was an attempt to restart California’s aborted hydraulic mining industry, but one that was ultimately unsuccessful. By 1893, the mines had sat dormant for almost a decade, and there was not enough money to build the required dams. Gold mining, once the heart of California’s economy, was fading, to be replaced by agriculture.

The primary purpose of the California Debris Commission evolved accordingly, and its work was increasingly focused on controlling Central Valley floods. Throughout the first few decades of the 20th century, reclamation of Delta lands continued. But there was increased concern over salt water compromising Delta water quality, and there was also a desire to transport water from the Delta to the San Joaquin Valley. The delivery and management of water resources in California have long been a joint state-federal effort. This practice had its origins in the Gold Rush described above, but came to fruition later with the construction of the Central Valley Project (CVP, the “federal project”) and the State Water Project (SWP, the “state project”). The Delta is the hub of the state and federal projects, and thus has been greatly impacted by them.

Shasta Dam and Shasta Lake; courtesy of USBR.

In 1931, Edward Hyatt (State Engineer with the Department of Public Works) finalized the State Water Plan, which set forth the infrastructure that would be needed to convey water to the south. In 1933, the legislature approved the CVP — as did voters, who passed a $170 million bond issue in December 1933. But in light of the Great Depression, the federal government took over the CVP project. The U.S. Bureau of Reclamation operates the system of conveyance and storage facilities that make up the CVP. Important CVP components include canals (Contra Costa, Delta-Mendota, Friant-Kern, and Madera), Friant Dam/Millerton Lake, Folsom Dam/Folsom Lake, and the Tracy Pumping Plant in the southern Delta. The Contra Costa Canal diverts water from the Delta to its namesake county; other water is diverted to the Tulare Basin and San Joaquin Valley. Another component of the CVP is Shasta Division, which includes the dam, reservoir, and power plant, and the Keswick Dam and power plant; among Shasta’s purposes were the storage and release of water to control the salinity of Delta water.

In the 1950s, the State of California planned the State Water Project, which consisted of power plants, and conveyance and storage facilities operated by the California Department of Water Resources. State Engineer Edmonton presented a plan in 1951, which was greeted by more skepticism and scrutiny throughout California than the CVP had two decades earlier; both the north and the south wondered if the other half of the state would try to compromise its water supply. But the legislature passed the Water Resources Development Act in 1959, followed up by voter approval in 1960; the legislature also passed the Delta Protection Act of 1959, which required that CVP and SWP operations be coordinated to ensure that Delta water was kept fresh enough for agricultural and other users. The backbone of SWP infrastructure is Oroville Dam and the multiple branches of the California Aqeduct, which facilitate the transport of water from Lake Oroville and the Feather River, through the Delta and the California Aqueduct, providing water to users throughout the state, including the North Bay and South Bay, the Central Coast, the San Joaquin Valley, and Southern California. The planning and construction of the state and federal projects is a story unto itself; in future posts, we will have something more to say about them in the context of the Delta.