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Northwest Growers Strategize to Face Drought

June 2015
by Peter Mitham
Drought Map
All of Oregon and much of Washington state are experiencing low water levels.

Yakima, Wash.—Water stopped flowing to irrigation canals in the Roza Irrigation District in mid-May, putting Yakima Valley grapegrowers on the front lines of an emerging drought scenario in the Northwest.

April saw Oregon Gov. Kate Brown add three counties to the list of 13 counties in her state facing a drought emergency (some entering their fourth year), while Washington Gov. Jay Inslee declared drought emergencies in three areas of the Evergreen State.

The past winter delivered record low snowpacks across the Northwest, with the spring snowpack dropping below levels seen in 2005, when drought was also widespread. The latest reports indicate Oregon’s snowpack was just 11% of normal May 1, while Washington state reported a snowpack just 16% of normal as of May 11.

Now, water has been shut off to canals in the Roza district as officials implement water-conservation plans standard in drought emergencies. A typical shut-off lasts upwards of three weeks.

While most irrigated districts in the Yakima Valley AVA enjoy senior water rights that guarantee them 3 acre feet of water per year, the Roza has junior water rights to service 72,000 acres of agricultural land including upwards of 12,000 acres of vineyard. This places it first in line for cuts when drought strikes; this year, the district anticipates a 50% cut in its water allotment. It has therefore cut the flow to its 545 miles of canals and will likely do so again in September.

This isn’t necessarily devastating to grapegrowers, said Wade Wolfe of Thurston Wolfe Winery in Prosser, Wash. “Wine grapes in the Yakima Valley require about 1 to 1.5 acre feet of supplemental water to produce a full crop, and even with a 50% allocation there should be enough water,” he told Wines & Vines.

Anticipating the shut off in the wake of the governor’s announcement of a drought emergency in April, growers will have drawn off water to ensure the soil has the moisture it needs, Wolfe said.

Most growers practice regulated deficit irrigation during the summer, but if the district shuts off water to irrigation canals again in September—as part of its drought response— some may modify their irrigation regime to bring in a bit more water prior to harvest. “In anticipation of the water being turned off early, they will likely alter (their) practice to supply additional water prior to harvest,” Wolfe said.

This is in keeping with the consensus of a panel at the Washington Association of Wine Grape Growers convention this past February, which concluded that deficit irrigation is best practiced early in the season. “Assuming a typical growing season, there should be adequate water for the wine grapes,” Wolfe said.

But as with all matters associated with water, it pays to read the fine print.

Wine grape producers often farm more than just grapes, meaning some may decide to divert water from a portion of their acreage for vineyard use; others, with properties enjoying senior water rights, may tap those rights to use their entitlement on less entitled properties.

The district, as well as individual growers, also has the ability to purchase water from senior rights holders.

While transferring rights is seldom a simple matter, especially in drought years, the strategy factored into the Den Hoed family’s purchase of an 80-acre property in the upper Columbia River Basin in 2008. However, the system aims to keep overall extractions level—and, in the current environment, conservation-oriented.

A reduced snowpack will mean less run-off, and that ultimately impacts aquifers, but sources contacted by Wines & Vines reported wells are in good shape. A sudden rainfall in mid-May delivered 2 inches of rain in some parts of Eastern Washington, too. The recent rain has muted the impact of drought declarations across the Northwest for many growers.

“We don’t see any significant problems for wine grapegrowers in the Walla Walla Valley,” said Duane Wollmuth of the Walla Walla Valley Wine Alliance. “Most of our irrigation comes from deep basalt wells, which at this time are in good shape.”

The drought spreading across Washington and Oregon has yet to reach British Columbia. While the province reported its lowest average snowpack in 31 years, the westernmost province is living up to Canada’s moniker of “the Great White North” with an average snowpack the envy of its southern neighbors. While the snowpack in the province’s southwest region is extremely low, with Vancouver Island reporting a snowpack just 14% of normal, the Okanagan snowpack was estimated at 57% on May 1,
and the province-wide average was 69%.

That hasn’t allayed concerns regarding dry conditions, however.

As elsewhere in the Northwest, the winter in the Okanagan was the warmest on record, and Kathy Malone of Hillside Cellars Winery in Naramata expressed concerns that conditions are dry enough to spark preparations for a potential repeat of the unprecedented wildfires of 2003.

“We’re already nervous,” she said.

Growers and winemakers worry that even if the fires don’t harm grapes, they could result in smoke-tainted wines if they occur after véraison.

The wildfires of 2003 put the issue on the B.C. industry’s radar, and growers in California and Washington state dealt with the threat in 2008 and 2012, respectively. With growing degree-days beginning to mount on the heels of an early bud break, managing drought conditions may be the key challenge for Northwest growers in 2015.

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