The Delta's Endgame

The delta - that labyrinthine confluence of the Sacramento and San Joaquin rivers, the biggest and most biologically significant wetland on the West Coast - is going belly-up like a sick carp.

True, it has been moribund for a long time, but that doesn't make its imminent demise any more tolerable. When the first white explorers entered the Central Valley, they found a horizon-to-horizon marshland of tules, sedges and willows where the two great rivers conjoined before debouching into San Francisco Bay. The waters teemed with chinook salmon, steelhead, green and white sturgeon and lesser fish, such as Sacramento perch, Sacramento blackfish, starry flounder and Pacific lamprey. The sloughs were choked with ducks and geese, vast flocks that blackened the dawn sky when they rose en masse to feed. Tule elk, beaver, grizzly bears, river otters - they were all here, in numbers unimaginable in our now populous and altered world.

Things began changing in the 19th century, when farmers reclaimed much of the region with an ambitious - if fragile - system of levees. The great marshes were drained, and the rich peat soils planted with everything from grains to orchard fruits. The tule elk and grizzlies were extirpated.

But the waterfowl still swarmed down from the north during the winter migration, and salmon still churned up the Sacramento and San Joaquin; in many years the fish were so plentiful they were pitch-forked out of the spawning redds and used as hog feed.

But as California grew, so did demands on the delta. Large-scale appropriations of water began in the 1950s, with the completion of the major dams anchoring the federal Central Valley Project, a mammoth system of reservoirs, aqueducts and pumps. The State Water Project, largely finished in the 1970s, diverted roughly equal amounts. Today, the two projects annually extract as much as 6 million acre-feet of water from two massive pumping stations located in the delta near Tracy.

The freshwater yield of the Sierra's snowmelt once surged through the delta and out the Golden Gate, creating a fluctuating brackish zone that sustained a vast food web, from plankton to the once-ubiquitous, now nearly extinct delta smelt, to salmon and steelhead. But with the completion of the government projects, the water went through home taps and San Joaquin Valley irrigation canals instead; the essential biological productivity of the delta wavered, and then dipped.

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