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Grounded Grapegrowing GL e NN MCG o U r T y N Vineyard Irrigation Strategies ature has blessed California with abundant rain this year, and this will be very helpful for most vineyards. After several years of very dry weather in some ar- eas, the rain is providing plenty of water in the root zone. (In my own vineyard planted along the Rus- sian River, the water table was one foot below the surface at bud break!) In areas dependent on irrigation for most of the vines' water needs, the rain will provide much-needed leach- ing of salts that may have accumulated from less-than-ideal wa- ter quality (the Central Coast comes to mind, as many irrigation wells have high amounts of dissolved minerals). The rains also will recharge depleted aquifers, fill irrigation ponds and provide our fields, forests and chapparal with a blush of healthy growth across the state. Snow packs in the Sierra are at near-record levels (more than 50 feet of snow has fallen in many areas), a delight to skiers and a promise of almost-normal water delivery to many ir- rigation projects serving growers in the interior valleys. Irrigation is a normal practice in most California vineyards, since we live in a Mediterranean climate where it doesn't rain for nearly half the year. Most Washington state vineyards are planted in the interior Columbia River Basin, which has a desert climate. Even Oregon, famous for its wet winters, has many new Pinot Noir vineyards planted to low-vigor rootstocks that may require a sip of water at the end of the growing season to finish ripening fruit. Water sources Surface water supplies are increasingly being allocated for pur- poses including urban populations, power generation, agriculture and nature (to preserve endangered fisheries and other environ- Find Irrigation Equipment & Suppliers Online www.winesandvinesbuyersguide.com Sprinkler irrigation requires considerable water compared to drip ir- rigation since the water is applied across the entire vineyard surface. mental needs.) Water development and large irrigation projects were initiated more than 100 years ago by visionaries like John Wesley Powell to entice people to settle in the arid west. It appears that this plan has accomplished its goals and then some. This finite supply of water will require all users to be as efficient as they can possibly be as a condition of continued water availability. Water supply is dependent on rainfall, which can vary hugely from season to season. As an example, 25 inches is the average annual rainfall at our family's vineyard on the west side of Paso Robles. Historically, actual precipitation over a 10-year period tends to be above that average two out of 10 years, near the aver- age for one or two years, and below average for the rest of the time. In that area, ponds won't fill every season. During the past two decades of extraordinary vineyard expansion, dropping water tables are a real concern in the Paso Robles region, since recharge doesn't seem to be happening at a sustainable level in many loca- tions. There are similar stories in many other parts of the west, where growers have opted to use wells when water from irriga- tion projects are curtailed due to drought years, environmental regulations or other interruptions in their water supply. Water is precious, and using it to maximum efficiency should be the goal of anyone who irrigates. No irrigation or dry-land farming There are some vineyards planted on deep, fertile soils that rare- ly need to be irrigated. In fact, vigor may be a problem. In these 80 Wines & Vines JUne 2011