In 2007 Oliver Wanger, a federal judge in California, ordered the huge pumping stations of the Sacramento Delta, the largest estuary on the west coast of the Americas, to reduce by a third the water they delivered to two aqueducts that run south to the farms of the San Joaquin Valley and onward to the vast conurbations of southern California. His reason was the delta smelt, a translucent fish less than eight centimetres (three inches) long that lives only in the delta and is considered endangered under federal law. The pumping plants were sucking in the fish and grinding them up. The next year, a "biological opinion" by the federal Fish and Wildlife Service reinforced Judge Wanger's order. Pumping from the delta remains restricted.

The consequences of these restrictions, which coincided with a drought that is now in its third year, reach far beyond one small population of fish. About two-thirds of Californians get at least some of their water from the delta, so with the stroke of a judicial pen the entire state, the world's eighth-largest economy and America's "fruit basket", entered an economic and political crisis.

Water has divided Californians since Mark Twain remarked that "whiskey's for drinking, water's for fighting over." But this latest conflict comes as America's largest state is politically gridlocked and holding back a national economic recovery. From Australia to Israel, parched places all over the world are now looking to California to see whether, and how, it solves one of the most intractable problems of thirsty civilisations in dry regions.

The pumping restrictions were a huge victory for environmentalists, who fill the ranks of one of the three armies in California's perennial water wars. With increasing success since the 1970s, greens have argued that the delta in particular, and California's dammed rivers and wetlands in general, are on the verge of ecological collapse and must be saved.

For the other two armies, the restrictions amounted to a stinging defeat. One army consists of urban consumers in the dry south, represented by the Metropolitan Water District, which supplies water to about 19m people, over half the state's population, and gets 30% of its supply from one of the two delta aqueducts. The authority has had to pay farmers in the Central Valley to give up their allocations and let their fields lie fallow, says Jeffrey Kightlinger, its boss. This year it also had to impose mandatory conservation measures.

The pain has been far worse, however, for the third force: agriculture. The farmers and farm workers who have been hardest hit live in the western San Joaquin Valley, which is supplied by the Westlands Water District, America's largest irrigation authority. Westlands has contracts to draw water from the other (federally financed) aqueduct. Tom Birmingham, its boss, says that, because of the drought and the pumping restrictions, it is receiving only 10% of its entitlement this year.

The result, says Mr Birmingham, is fallow land, farm workers being laid off and "people standing in food lines for hours". In some areas unemployment runs at 40%. There are scenes reminiscent of John Steinbeck's "The Grapes of Wrath", though most of the poor and jobless are not white "Okies", but Latinos. Just as the "dust bowl" swept across the Great Plains in the 1930s, so in the San Joaquin Valley, fields are reverting to desert and signs read, "Congress created this dust bowl".

"All my almond trees are going to die," says Shawn Coburn, a farmer in the area. He began farming in 1992 and has done everything he can to use water more wisely. He has planted fewer tomatoes and melons and more almonds and wine grapes because these crops drink less and yield more. He says he has conserved all he can with technology. Like other farmers, he has also dug wells to tap the shrinking aquifers, even though he knows he is making the entire valley floor sink. In one place, he says, the ground around a telephone pole has dropped by six feet (nearly 2 metres).

The environmentalists are not denying that their victory has cost agricultural jobs. But Jonas Minton of the Planning and Conservation League, a Californian non-profit outfit, thinks that a public-relations firm paid by the farmers has been exaggerating their misery. In any event, he says, the problem is not a court ruling but a system in which the state has pledged eight times as much water to title-holders as exists in nature and therefore cannot, of necessity, give everybody his due.

Jim Metropulos, a lobbyist at the Sierra Club, another environmental group, agrees. "I cannot control a drought," he says. Westlands' Mr Birmingham can complain, he says, but, "Why do we have to give him more water?" It so happens that Westlands' water rights rank below those of other title-holders and "there is simply not enough water to go around."

Angry and bitter words are thus flying on all sides, which is as it has always been in California. But this time the crisis has become so severe that the state's legislators in Sacramento, notoriously incapable of agreeing on anything serious, including a punctual budget, appear on the brink of a breakthrough. A complex package of legislation was almost passed in September and failed only because time ran out in that session. The legislators are now talking again. A deal could emerge for a vote within weeks.

Timothy Quinn, director of the Association of California Water Agencies, which represents the suppliers of about 90% of the water consumed in California, credits the pumping restrictions for this progress. He says Judge Wanger forced all sides to acknowledge the seriousness of the situation. His decision was the "equivalent of an earthquake" whose shock was severe enough to shake California's democracy. Therein lies, perhaps, the opportunity.

The details of the legislation negotiated so far are complex, but its main feature is a phrase, "coequal goals"-though how coequal goals differ from equal ones is not clear. For most of the previous century, says Mr Quinn, California and the entire West had an "extraction mindset" according to which man was meant to subdue and exploit nature. In water matters, this meant ever more dams, reservoirs and aqueducts. However, over the past four decades the environmentalist mentality grew up as an alternative, emphasising "sustainable" use of nature.

California's water policy in the past has swung "like a pendulum" between these two principles, depending on which lobbyists have won the latest victory, says Lester Snow, the director of California's water department. Enshrining the objectives of both sides as "coequal" in state law would thus mean progress, by requiring all factions to consider both fish and farms, both nature and the economy, both sustainability and reliability.
"It's a huge step," agrees Mr Kightlinger of the Metropolitan Water District. In practice, most water managers in the state already take sustainability seriously, but making equality official would force all sides to "play nicely", he thinks. The old rivalry between urban and agricultural water use has already faded, he says, and today's animosity between both of them and the greens may also subside.

Westlands' Mr Birmingham says that, in practice, water usage has already become equal. Whereas agriculture used to consume 80% of the state's water supply, today 46% of captured and stored water goes to environmental purposes, such as rebuilding wetlands. Meanwhile 43% goes to farming and 11% to municipal uses.

The environmentalists, as today's top dogs, are less excited about equal goals. At present the state's water infrastructure is run with a single goal, which is to protect nature, and this, says Mr Metropulos of the Sierra Club, provides complete clarity of purpose. Equality, he thinks, will only lead to new conflicts and litigation. When the time comes for trade-offs, he asks, "Who's going to make the decision? It is undefined." He is lobbying against the legislation, although he is unlikely to prevent it.

The next layer of legislative proposals will concern the Sacramento Delta, the inland network of streams and rivers, many contained by dykes and levees, that form the hub of California's water infrastructure. Californians hate rain but love water, so three-quarters of them live in the arid south, spurn the wet north where three-quarters of the rain falls, and expect water to come to them by pipe, canal or aquifer, preferably courtesy of the taxpayer.

The Sacramento and San Joaquin rivers and their tributaries, carrying the rain from the north and the melting snowpack from the Sierra Nevada in the east, meet in the delta and flow out through San Francisco's Golden Gate. The trick has always been to intercept the fresh water in the delta before it gets salty and to send it south as well as west to the San Francisco Bay area.

Those in the south get it through two huge infrastructure networks. The federal Central Valley Project, dating from 1937, uses 20 upstream reservoirs and two pumps to take water to the southern Central Valley, largely for farmers. The State Water Project, begun in 1960 by Pat Brown, a visionary governor, uses another 22 upstream dams and reservoirs and its own pumping plant to send water into the other aqueduct, largely for urban use.

By pumping fresh water south, however, these two projects wreak ecological havoc. Sceptics like to inveigh against the unprepossessing delta smelt, which George Radanovich, a Republican congressman, has called "a worthless little worm that needs to go the way of the dinosaur". But other fish species such as the Chinook salmon, the steelhead and the longfin smelt are also threatened, and each species is a part of a complex food chain. About 25% of the state's sporting fish and 80% of its commercial fish live in or migrate through the delta.

The pumps kill fish and other species, and not just by grinding them up. They also change, and occasionally reverse, the water flow of the small rivers in the delta's vast labyrinth of streams, creeks, sluices, islands and marshes. In natural circumstances, the delta is brackish and its salinity changes with the tides. The pumps, by drawing in river water, keep the delta water artificially fresh. Native species die, invasive species thrive.

Beyond that, the ageing delta's levees are a human disaster in the making. The delta sits on top of seismic faults that may rupture, and many of the islands that make it up are below sea level. A large earthquake could disrupt the state's water supply and inundate the delta itself.

The best answer, says Ellen Hanak, a water expert at the non-partisan Public Policy Institute of California, is to build either a canal or a tunnel around the delta. Fresh water could then be tapped upstream on the Sacramento River and conveyed round the delta to the aqueducts without grinding up fish, reversing river flows or changing the delta's salinity, which would again fluctuate with the tides. The water going south would be fresher too. A canal would thus "separate the water for the fish from the water for the economy and the people," says Mr Quinn.

The trouble is that such a peripheral canal is a political hot button. In 1982 Jerry Brown, Pat Brown's son and California's governor at the time, put a canal on the ballot but the voters rejected it. Even now, many people are passionately against it. Farmers and residents in the delta itself fear that a bypass would mean that politicians and public money would abandon them amid their disintegrating levees, and others would grab their water. The Sierra Club is against a canal because "it is not going to make new water" and "we want to reduce exports from the delta" rather than reroute its flows, says Mr Metropulos.

The legislation under negotiation is therefore taking a different approach. Instead of decreeing a bypass canal or tunnel outright, it seeks to establish a new authority with the power to take this decision itself. This is sorely needed. Mr Snow at the water department has counted more than 200 entities, from cities and counties to fisheries and reclamation or irrigation districts and even mosquito-abatement boards, that share responsibility in such a way that nobody has any. A new and nimble "Delta Council" would seize authority from all of them and actively manage the delta for the first time. And it could do this by building a canal.
One sign of progress by Californian standards is that, if the deal gets stuck, it will be largely over relatively banal issues such as money. The legislation is likely to mandate investment in new dams and reservoirs, which appeal to Republicans, and also in waste-water recycling, desalination and groundwater storage, which are the environmentalists' and Democrats' preferred sources of water. But Arnold Schwarzenegger, the Republican governor, has said that he will veto any legislation that does not include billions of dollars in new bonds to pay for these new projects.

State Republicans, allied to farmers, are pushing for "general-obligation" bonds that would be put to the voters on a ballot and, if approved, paid out of general state tax revenues. Democrats are concerned that the interest on such bonds would aggravate California's continuing budget dispute and come at the expense of education, health care and other things they mind about. They prefer bonds that would be repaid by the users of new dams, ie, the water agencies that can pass costs on to their customers. Water thus trumps ordinary politics. Republicans, who usually claim to be against big government, want taxpayers to pay; Democrats, generally accused of being big spenders, want to match infrastructure costs with water revenues to send the right price signals.

The legislation is likely to encourage water conservation by setting targets for reducing consumption. One guess is that it may call for a cut of 20% per person by 2020. That cannot be a bad idea. On the other hand, little progress is being made on monitoring groundwater levels, even though many aquifers are shrinking. Some of the state's water districts voluntarily measure groundwater levels, but Republican legislators have opposed making such reporting mandatory on the ground that it would mean trespassing on private property. "California is the last bastion of the Wild West when it comes to groundwater," says Ms Hanak. It may stay that way.

Whatever happens, the legislation will not deal with the long-term threats to California and its neighbours. Climate change is already showing up "in the data", says Mr Quinn. The snowpack of the Sierra Nevada, California's most reliable water-storage system, is shrinking and may stop yielding predictable run-off in the spring and start producing sporadic and unusable, not to mention disastrous, floods. The delta is already below sea level and, as the sea rises, it may be submerged. Even today the south is a desert wherever irrigation does not reach. It will become even drier.

For professional water managers such as Mr Kightlinger, this makes the continuing talks in Sacramento frustrating. "‘I'm for screwdrivers but not for hammers': that's how they talk," he says. But he thinks all the tools are needed if California's population and economy are to keep growing.

Of those tools, water recycling, a euphemism for cleaning up sewage, is perhaps the most promising. Recycled water is local and does not disappear in a drought. But many consumers continue to struggle with the idea that what they are drinking today someone else restored to the water system yesterday. Desalination, which removes minerals from seawater or, more often, brackish groundwater, is an alternative. But it takes a lot of energy to push water through the dense filters that remove unwanted salts and other molecules. Water markets, which allow those with too much water to trade it easily with those who have too little, could also help.

If there is to be any progress, however, Californians first have to bury their hatchets. If the talks stall, the political fallout will be big. Tom Campbell, the most thoughtful Republican candidate for governor in next year's election, thinks water is by far the most important issue facing the state. Willie Brown, a former speaker of California's Assembly and mayor of San Francisco, believes "a political earthquake is rumbling in the Central Valley over water, and it could cause a real tsunami for the Democrats in the 2010 elections if they don't handle it well," since Democrats are more associated with environmentalists and several of them face re-election.

For the same reason, if the negotiations succeed, even a mediocre deal would amount to the most important water legislation since the era of Pat Brown, says Mr Quinn. Westlands' Mr Birmingham feels that many environmental groups, such as the Natural Resources Defence Council and the Nature Conservancy, have become "genuinely interested in working with water agencies", even though others are "using water as a means to limit housing development".

"I am very optimistic for the long term," says Mr Birmingham. "The real question is how are we going to survive between now and the time when new conveyance facilities become available," which could be a decade or more. "If we continue to live under the existing biological opinions, irrigated agriculture in the western San Joaquin Valley cannot be sustained," he says. For farmers such as Mr Coburn and his 26 Latino workers, never mind his almonds and wine grapes, the help may arrive too late. This is perhaps the only thing they have in common with the delta smelt.

 California's water wars: Of farms, folks and fish, Economist, Oct. 22, 2009, at 27

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