Decline Seen in Sacramento River's Fish Population California's Sacramento River Delta's expansive system of pumps and irrigation canals is responsible for helping the San Joaquin Valley be one of the most fruitful agricultural regions in the world. But increased farming has diverted more and more water out of the Delta, and that may be threatening fish.

Decline Seen in Sacramento River's Fish Population

Decline Seen in Sacramento River's Fish Population

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California's Sacramento River Delta's expansive system of pumps and irrigation canals is responsible for helping the San Joaquin Valley be one of the most fruitful agricultural regions in the world. But increased farming has diverted more and more water out of the Delta, and that may be threatening fish.


The Sacramento River Delta has seen its population of fish plummet over the last three years. State and federal scientists say it is too early to reach a conclusion about the cause of the decline. Still, preliminary findings suggest that the primary cause may be water from the delta going south for irrigation, and that has California's big agricultural industry worried that it will get less water. NPR's John McChesney reports.

JOHN McCHESNEY reporting:

Satellite photographs of the Sacramento-San Joaquin River Delta look like a vascular system of thick arteries and thinner capillaries branching out from the two rivers, which drain most of the state.

Mr. BARRY NELSON (Natural Resources Defense Council): The Bay-Delta is the largest estuary on the West Coast of North or South America.

McCHESNEY: Barry Nelson is with the California office of the Natural Resources Defense Council.

Mr. NELSON: It's an extraordinary system, the most important salmon-producing system south of the Columbia River. It's a remarkable natural resource, tremendously important for migrating water birds. But overlaid on top of that is the most complex plumbing system in the world.

McCHESNEY: That plumbing system delivers water from the delta to California's farmers and cities. Two-thirds of the state receives its drinking water from the delta, and without its water, the $30 billion agricultural industry in the Central Valley wouldn't exist.

(Soundbite of machinery)

McCHESNEY: The humming heart of that plumbing sits on a channel in the center of the delta in two low-lying concrete structures which belie the immensity of what's going on inside. This one is run by the federal Bureau of Reclamation.

Mr. JEFF McCRACKEN (Bureau of Reclamation): What you're hearing now and what you're seeing is this is one of the pumps that's operating now to export the water.

McCHESNEY: Jeff McCracken points up to a massive steel shaft nearly three feet thick and 40 feet high, spinning a pump below. There are six of these pumps in a row here. Each one can deliver 7,500 gallons of water in one second. In a year, these pumps irrigate three million acres of farmland and supply drinking water for a million people. From here and another bigger state-run pump next door, the water pours south, down a system of huge concrete-lined rivers.

(Soundbite of machinery)

McCHESNEY: And near the pumping station is a fish collection canal, where trouble may be brewing for this vast water system. By the way, the protective grates here keep out big fish, but the small fry slip through. Again, Jeff McCracken.

Mr. McCRACKEN: If a fish happens to go through this, it'll get moved through a couple of tubes at different spots down here, and ultimately move into our fish collection facility where we can capture those fish and return them back to the delta.

McCHESNEY: It's not known precisely, though, how many fish are captured and returned, and how many are killed when they're sucked through the big pumps. But Bruce Herbold of the US Environmental Protection Agency told a recent gathering of scientists we do know that some fish species are disappearing at an alarming rate.

Mr. BRUCE HERBOLD (EPA): We looked at the abundance of fish as sampled by Fish and Game, and noticed that for three years in a row, we had had pretty much record low abundances of the fish that the sampling program is designed to sample.

McCHESNEY: Among those fish, the tiny delta smelt is considered a key indicator for the health of the delta ecosystem. It's also on the endangered species list, and the dramatic decline of the smelt, the striped bass and other species happened at the same time lots more water was diverted from the delta during the winter months.

Mr. HERBOLD: Where they used to take about two million acre-feet on average, now they're taking almost three million acre-feet on average in the months when these free-spawning adult fish are swimming up to the delta to spawn.

McCHESNEY: Scientists like Herbold stress that there are other possible culprits in this decline, like toxic runoff from the farms and cities or invasive species that devour fish food. But if water exports from the delta are the biggest reason for the decline, the implication for California agriculture could be enormous. Farms consume 10 times more water from the federal project than the cities do, and the biggest customer, 150 miles to the south, is the Westlands Water District, the largest irrigation region in the world. Farmers here reap rich harvests of everything from cotton to lettuce.

(Soundbite of tractor)

Unidentified Man: (Spanish spoken)

McCHESNEY: Long rows of green iceberg lettuce stretch far ahead of a tractor slowly pulling a wide trailer which resembles a huge winged insect. Workers walk behind a dozen work stations perched on these wings, some cutting the heads and stripping the outer leaves, others bagging and pitching them into cartons.

Mr. TOM BIRMINGHAM (Executive Director, Westlands Water District): During the months of November and December as well as in April, May and into early June, 95 percent of the lettuce that is consumed in the United States comes from Westlands Water District.

McCHESNEY: Tom Birmingham is executive director of the district, and he proudly shows off its wares and its technology. He points to plastic pipes poking out from the ends of every raised row of lettuce--drip irrigation.

Mr. BIRMINGHAM: Farmers in Westlands, because of their use of technology like drip, have achieved as much as a 93 percent irrigation efficiency, which means that 93 percent of the water that is applied to the ground is used by the crop for growth.

McCHESNEY: Birmingham is careful to emphasize this efficiency because Westlands is a favorite whipping boy for nearly everyone--environmentalists, fishermen, cities--who believes that too much water is being taken away from the Sacramento Delta. Westlands is an area, they say, that should never have been irrigated in the first place.

Mr. TOM STOKELY (Natural Resources Planner, Trinity County): We don't believe that the agricultural practices there are sustainable in the long run.

McCHESNEY: Tom Stokely is natural resources planner for Trinity County, 300 miles to the north of Westlands. Stokely says some of Westlands water comes from the Trinity Reservoir, and when we fought to send more water down the Trinity River to keep salmon alive, Westlands opposed that move in court.

Mr. STOKELY: Soils in Westlands are such that they contain high amounts of selenium, molybdenum, arsenic, things like that, and when they irrigate those lands, it basically causes toxic runoff.

Mr. BIRMINGHAM: I've heard people comment that it might have been a mistake to irrigate lands within Westlands, and maybe it was a mistake.

McCHESNEY: Again, Westlands' Tom Birmingham, sitting in his pickup next to an irrigation pump.

Mr. BIRMINGHAM: But the reality is, the lands have been irrigated. Much of California is an artificial construct. The Southern California metropolitan area exists because of the ability to import water to that area from distant regions. This land is some of the most productive agricultural land in the world.

McCHESNEY: Nevertheless, many, like Trinity County's Tom Stokely, believe that if there needs to be a reduction in pumping from the delta, the solution is to shut down some farms in the Westlands.

Meanwhile, the scientific team that raised the alarm will continue its research, trying to determine if the human appetite for water is indeed killing the delta fish.

John McChesney, NPR News, San Francisco.

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