Wines & Vines

July 2015 Technology Issue

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28 WINES&VINES July 2015 Grounded Grapegrowing T he 2014-15 water year may be a turning point in California water policy if present weather trends continue. The National Oceanic Atmospheric Administration has classified most of the state as being in "extreme drought" or "exceptional drought." During the past five months, a persistent high-pressure ridge above the North Pacific (known by many in the media as "the blob") has resulted in extreme record warmth ranging from 2° to 8° F above normal in the west. These conditions have resulted in the lowest snow packs on record for California—only 5% of normal. Much of the Pacific Northwest is experiencing the same conditions. Ac- cording to a recent survey by the Farm Water Coali- tion, 41% of farmland in California using surface water will have 80% less of its usual supply this year due to drought impacts. Groundwater, if available, will have to make up the difference if growers want to continue farming their orchards, vineyards and fields this year. California Gov. Jerry Brown has called for a 25% reduction in water use for the state. In a normal year, according to the California Department of Water Resources, groundwater makes up about 40% of total agricultural and urban uses. In a drought year, it may make up as much as 60%. Some areas are totally dependent on groundwater, as there is no surface water supply available. California's water supply for urban and agricul- tural use is stored in three ways. Water stored as snow in the mountains melts during the summer as the season progresses. This melted snow is then stored in surface reservoirs as it runs off and is distributed. Finally, groundwater is used in places where or when surface water isn't available. In 2015, snow and stored water in reservoirs are critically low. Surface water California has one of the most sophisticated and well-engineered water supply systems on the planet. The idea of irrigating western lands goes back a long way, with politicians and promoters realizing that the west wouldn't be settled without water. John Wesley Powell, the famous explorer of the Colorado River Canyon and the second director of the U.S. Geological Survey (1881-94) thought that only 2% of the west's agricultural land (mostly adjacent to rivers) was suitable for irrigation. He suggested that the rest be held for grazing and conservation. Other people vigorously disagreed—particularly railroad barons and other promoters who wanted to sell real estate to po- tential settlers. Powell is fa- mously quoted from an 1883 irrigation conference, where he said, "Gentlemen, you are piling up a heritage of conflict and litigation over water rights, for there is not sufficient water to supply the land." It seems he was right. More than 140 years ago, Cali- fornia began to outline ideas for water de- velopment n GLENN T. McGOURTY Implications of Drought on California's Water Supply KEY POINTS This column summarizes the effects of drought on California agriculture and gives a brief history of the state's water infrastructure. Overdrafts of groundwater are troubling to state agencies and lawmakers, and measurements of groundwater levels will be required. Water conservation, re-use of wastewater and the practice of groundwater banking are likely to be key parts of future water management. John Wesley Powell famously said in 1883: "Gentlemen, you are piling up a heritage of conflict and litigation over water rights, for there is not sufficient water to supply the land."

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