“Whiskey’s for drinking. Water is for fighting over.” – Mark Twain.

In California, they know better than most about the competition for water – just watch the movie "Chinatown." Now scientists in the state have disclosed a new front in the battle for that precious resource, with an at-risk fish species on one side pitched against Californian winemakers on the other.

Investigating death rates for juvenile steelhead trout, biologists from the University of California at Berkeley have found a link to low summertime water levels and the amount of vineyard acreage upstream. It’s not a proven causal connection, lead author of a recent study Theodore Grantham cautions, but it’s evidence that by drawing off water from local rivers for irrigation, vineyards are harming the chances of a species that in some parts of the state is approaching extinction.

“The situation for these fish is quite dire,” says Grantham. “Historically, steelhead occurred all through California, which is the southernmost extent of their range, but due to a whole lot of factors we’ve seen a dramatic decline.”

Previously, both scientific research and rehabilitation efforts had concentrated on some of those other factors, such as habitat degradation, water quality, and the spread of dams blocking access to traditional spawning grounds. (Steelhead have what the biologists call great “site fidelity,” meaning they will attempt to return year after year to the same rivers.) As Grantham remarks, there has been rather less appetite to investigate the possibility that the volume of water in the rivers could be part of the problem.

“There has been a lot of effort gone into restoring habitats, creating pools and so on. The issue of water quantity, however, has been neglected, partly because people assumed it wasn’t as big a problem, but also because water is a subject that gets very political very quickly here, and it’s difficult to tackle. It’s much easier to plant some riparian vegetation than to secure water rights for the ecosystem.”

In parts of California, the wine industry has less impact on river levels than other land users. But in Grantham’s bailiwick – the coastal watershed from a couple of hours' drive north of San Francisco to the Central Coast – vineyards have become the dominant form of agriculture in the past 20 years. “We’ve seen a huge expansion in total acreage of production, driven by the returns from wine.”

It’s not only irrigation draw-off during the dry season that’s worrying conservationists. Vineyards also make heavy use of waterways during times of frost, with overhead sprinklers deployed en masse to create a layer of ice around the budding plants. (It’s not as self-destructive as it sounds – in the process of freezing, the water creates a protective warmth barrier.) Unfortunately for the steelhead, every vineyard in a frost-prone neighborhood tends to draw off water at the same time – in fact, in a really bad frost year, as much water gets used in a fortnight as in an entire season for standard irrigation needs.  

Answers? Grantham argues that Californian vineyard owners need to boost their winter water-storage efforts. At least 80 percent of the annual rainfall in his part of the state comes between November and March. “I’m not advocating big dams, but if we could store more at the local level, perhaps the industry could reduce its impact during the summer.”

He’s optimistic that a “substantial subset” of wine people are committed to saving the steelhead. “My hope is that this research forces everybody to the table to consider alternatives.”

But several winemakers are already there. At Quivira vineyard, in Sonoma County, efforts to create pools and restore the riparian strip of the irresistibly named Wine Creek are already well advanced. As well, Quivira recently replaced its frost-protection system, which drew heavily on nearby Dry Creek, with wind machines. Chief financial officer Dave Lese says owner Pete Kight is committed to doing his bit for the steelhead.

“As winemakers, we are definitely conservation minded,” says Lese. “It’s a pretty significant investment that the owners here have made, with the idea of improving – or at least not harming – water conditions for steelhead and other fish.”

Other Sonoma wineries have taken up the cause. Quivira’s sister winery, Steelhead Wines, for example, is a donor to a local conservation initiative run by international organization Trout Unlimited. Known as the Water and Wine project, it involves partnering grape growers and wineries to restore salmon and steelhead habitat and to develop more fish-friendly water-management practices. 

Steelhead Wines owner Katy Leese says the wider initiative grew from a realization that wineries such as Quivira could only do so much in isolation, and that others upstream and downstream needed to be encouraged to play a role.

For Steelhead’s part, she adds, “we feel it’s our responsibility to make sure that water is not just there for human use. We want to help to bring the steelhead back.”

Leese believes that, given a gentle push, Californian winemakers will do the right thing. “A lot of wineries here are already looking at sustainable practices, and there are discussions about how to conserve water and do things better. And the great thing is that winemakers tend to have a lot of smarts and to be highly innovative.”

Those concerned for the fate of the steelhead trout can only hope so.