by Lucero Radonic, WRRC Graduate Outreach Assistant
The state of California started keeping track of its annual precipitation in 1849, and the year 2013 has been the driest on record. With conditions in 2014 showing no signs of improvement, Governor Jerry Brown declared a drought emergency for the state in January. According to data from the U.S. Drought Monitor, released on April 1, 2014, 68.76 percent of the state is experiencing extreme drought with another 23.49 percent on the Central Coast and San Joaquin hydrologic regions undergoing exceptional drought conditions. This is a substantial increase from only a year ago, when no part of California reached extreme or exceptional drought conditions, and severe drought affected no more than 24 percent of the state.
Running for roughly 400 miles north-to-south in western California, the Sierra Nevada Mountains are the state’s major source for water supply. Most of the drinking water for more than 23 million people in California and one-third of the water supply for the state’s agricultural land comes from the spring snowmelt. Water from the Sierra Nevada also makes up half the inflow to the Sacramento Delta, which supports the West Coast’s largest estuary and provides water to irrigate more than 3 million acres of agricultural land.
Less winter snow in the Sierra Nevada means less spring runoff and less water availability across the state. To forecast runoff and water availability, every winter season from January to May, teams of skiers conduct monthly snow surveys at pre-selected sites high up across the Sierras: surveyors ski for miles to reach the sites, drive aluminum tubes into the snow to measure depth, and weigh the samples to gauge water content. As April is historically the time when snow is at its peak, data from this month’s survey is considered the most accurate snapshot of how much water will be available for future use. This year’s April survey revealed that snowpack levels in the central section of the Sierra Nevada were 38 percent of average levels, while the northern and southern sections were at 23 and 31 percent, respectively. Although the levels have increased from earlier in the year, this is the lowest level since electronic record-keeping began in 1960. Dismal snowpack today indicates that drought conditions will continue to affect the state for the next years.
To make matters worse, the state’s reservoirs are also running below average levels. About 75 percent of annual precipitation in California falls north of Sacramento, but more than 75 percent of the demand for water comes from south from it. To balance supply and demand, California has seven major systems of reservoirs, aqueducts, and associated infrastructure to capture and deliver water within the state. These large-scale systems allow for the redistribution of water largely from the north to the south. Two of the most important projects are the federal Central Valley Project and the State Water Project, which bring water from Northern California for delivery to agricultural and municipal users in the San Joaquin Valley, parts of the San Francisco Bay Area, and Southern California. The Department of Water Resources reported that Lake Oroville, which is the State Water Project’s largest reservoir, is at 49 percent of its capacity. This is 64 percent of its historical average for this time of the year. Conditions are similar at Shasta Lake, the federal Central Valley Project’s main reservoir, which is at 48 percent of its capacity. This is 60 percent of its historical average. Similarly, the San Luis Reservoir, a critical reservoir for the State Water Project and the Central Valley Project, is at 42 percent of its capacity, roughly five percent below its historical average.
The California agriculture industry is the largest of any state in the country: California farms produce about half of all U.S. fruits, vegetables, and nuts, and they generate about $45 billion in annual revenue. California farmers are facing tough choices brought about by extremely limited water supply and high cost of irrigation. In the last two decades about one-third of farmland in California underwent a transformation from annual crops to perennials. It is estimated that about 3 million of the approximately 9 million acres of irrigated agriculture in California are now nut orchards and vineyards. The Golden State is the nation’s top producer of water-intensive tree nuts with California producing 80 percent of the almonds produced worldwide and 39 percent of the pistachios. Nut production brings over $7 billion in sales every year, with almonds far outpacing other nuts at $6.2 billion in 2013. Grapes, another profitable crop, generated $4.45 billion.
However, these profitable perennials impose significant challenges at times of drought. Fields dedicated to growing annuals like lettuce and tomatoes can be fallowed during drought and replanted later, without an investment loss. This is not an option for nut trees, which need ten years of growing and a steady supply of water before they yield enough to pay for themselves. Furthermore, water deficits affect nut orchards not only in the year in which stress occurs, but also in the following seasons when nut size and load are generally reduced.
Faced by the consistent water requirement of these trees, farmers are letting orchards dry up and in some cases making the tough decision to tear them out. Some farmers hope that by sacrificing a percentage of their orchards, they will have enough water available for the remaining trees during the drought. For example, one farmer in Fresno County gave up 1,000 acres of his almond orchard to keep the remaining 4,000 acres alive. By cutting down the trees, he estimated a loss of approximately $10 million in revenue. Exact numbers of how many acres of orchards have been sacrificed since the drought intensified are not available, but farmers believe that the number will only increase as snowpack in the Sierra Nevada Mountains remains below historical levels.
Spring rains have provided some relief but were not sufficient to end the drought challenging state water users.