Almonds, walnuts, pecans, pistachios and hundreds of fruits and vegetables grow in the deep rich soil of California’s Central Valley. My Farmers Market sells certified locally-grown produce and most of the year offers a vast variety. When farmers in colder areas have finished their harvest, we enjoy our winter crops — broccoli, greens, garlic, mandarin oranges, kiwis, apples, potatoes, squash, olives, radishes, bok choy, persimmons, and pomegranates. Plus the nuts. Every almond you eat probably comes from the Central Valley as does incipient dairy products (alfalfa). As much as I relish our bountiful harvests, I know we need fewer nuts — and less cheese.
The Central Valley (CV) holds about one-sixth of the irrigated land in the U.S. and produces more than 250 crops and provides nearly half the U.S. grown fruits, vegetables and nuts. Eighty-two percent of the world’s almonds grow here. It is the state’s number one crop, worth $5.33 billion in 2015. The CV productivity comes from our mild winter climate, deep rich soils, and a regular supply of water. The historic hydrology is responsible for the soils. But we newcomers from the Old World messed it all up soon after we arrived.
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The 400-mile-long Central Valley is composed of two major portions named after their largest rivers. North is the Sacramento Valley and south is the San Joaquin Valley (divided into two basins) with the Delta between them.
The Sacramento River system begins near Mount Shasta, flows south of Sacramento to Stockton, then west through the Delta and into the Pacific Ocean. The San Joaquin River flows north through the southern half of the CV and historically merged with the Sacramento River in Stockton and then on to the ocean. The Kern River is the main water course in the Tulare Basin.
Prior to European settlement in the mid-1800’s these rivers were braided channels in the vast flood plain of the valley floor and might expand their width several miles in winter due to floods. The Sacramento River was twenty miles wide or more. The San Joaquin River wasn’t as broad but, like the Sacramento, tributaries flowed through alluvial flood plains in winter, spring and early summer creating marshy wetlands and extensive riparian forests.
Historically riparian habitat was 1.6 million acres of the total 13 million acres of CV wetlands. In spring, the water subsided leaving behind a sea of wildflowers and native grasses grazed by elk, antelope, and deer. Only one percent of the native grasslands remain.
Large portions of the valley often flooded in winter and the receeding water deposited alluvial soil, helping build the deep topsoil that now supports California agriculture. Prior to the mid-1800’s, the 13 million acres of the Central Valley included 4 million acres of wetlands. A USFWS report on historic and present wetland habitats in the Central Valley estimated 100 to 200 thousand acres of the former 4 million acres of wetlands remained by the 1977. Conservation efforts since then have increased the wetland acreage to about 200,000 acres.
European settlers arrived in the 1840’s. Conversion of wetlands to agricultural lands and restrictions of the rivers’ flows began in 1850. Farmers built levees to protect farmlands and in the 1870-80’s the Army Corps of Engineers surveyed the Sacramento River region and proposed a project using pumps, dams and canals to minimize flooding and move water to central and southern California, particularly the San Joaquin Valley. Water diversions continued as settlements increased and in the 1940’s the San Joaquin River was dammed and diverted. By 2010 it no longer flowed to the Delta. Attempts to restore the river’s flow to the ocean began in 2013 but are hampered by drought and agricultural demands for water.
During severe drought in 2015, farmers nevertheless planted 77,000 acres of new and 27,000 acres of replacement almond orchards. New plantings were primarily in the drier San Joaquin Valley where groundwater extraction caused 1.25 feet of soil subsidence in two years. Prices for almonds have dropped 50 percent, resulting in land values decreasing 25 percent. New almond plantings often use micro-irrigation now to reduce evaporation and deliver precise amounts of water. But this also increases problems with soil salinity. Micro-irrigation installation and maintenance is costly compared to the water-wasteful flood irrigation used in the past, but flooding helped limit salinity.
Last year at this time California was still in serious drought conditions with state-mandated water restriction. But we were lucky. A bit of rain in October, more in November and then higher rainfall in December brought us to 16 inches of rain. By the end of rainy season 2016 most of the reservoirs in central and northern California were nearly full and the snowpack was 100 percent of normal. The southern half of the state received much less water. In May 2016, the water restrictions were lifted, an action that many conservationists consider hasty.
Perhaps Governor Brown was deluded because we had tule fog last winter. Excitement over tule fog is new. It used to be an obstacle that kept planes from flying and forced drivers to follow pilot cars on highways due to poor visibility. A 2014 study found that tule fog has decreased by 46 percent over the past 32 years. Tule fog forms when the ground is soaking wet and night temperatures cool down fast. Wintering birds are adapted to the thick fog and the cherry, almond, peach and apricot orchard trees benefit from a period of chilling (vernalization) that prepares the fruit buds to grow in the spring. As recently as the 1980’s, the entire valley might be dense with tule fog to 1,000 foot elevation for a week or more. Now the tule fog flits in for a few hours overnight and dissipates after sunrise.
This year’s rainy season began promisingly with above average rain in the northern portion of the Central Valley — 285 percent of normal so far in the Sacramento Valley. The Delta had normal or slightly higher rainfall, and the San Joaquin Valley barely has half normal. While more rain is predicted for the weekend, it is still concentrated in the northern areas with less or none in the southern.
Here’s the November 8, 2016 drought map for California. Several years of above-average rainfall (135-160% of normal in the north, with 198% in the San Joaquin) are needed for soil moisture levels, reservoirs, and groundwater aquifers to recover.
Not all the nuts in the Central Valley are tree crops. Those policies/values that approve water for and planting of the 77,000 acres of new almond orchards are nuts, too. Almonds are perennial crops that can’t be left fallow to conserve water during exceptionally dry periods. Growing alfalfa, another water guzzling perennial crop, also is nuts, and for the CV it is even less suitable than almonds. Managed properly with reasonably sited acreage using micro-irrigation, almonds are a valuable crop. But alfalfa is flood or sprinkler irrigated — incredibly wasteful systems. Despite the high water need, alfalfa is the state’s highest acreage crop. About 20 percent of the nation’s groundwater is pumped from aquifers here and it’s the second most pumped aquifer system in the nation.
The alfalfa to dairy pipeline is draining the Central Valley. Dairy is the state’s number one commodity and milk brought in $6.29 billion last year. More water is applied to alfalfa in California than any other crop. Alfalfa accounts for 20 percent of all agricultural water use. And in the San Joaquin Valley, which produces 61 percent of this alfalfa, extra water must be applied to leach salts from the soil and to compensate for irrigation inefficiencies.
Even when we have a wet winter, as in 2006, alfalfa suffers. One farmer planted 500 new acres of alfalfa that was drowned out in December. He replanted again in April and all but 70 acres was drowned out in March. It’s the dairy industry that uses alfalfa and the U.S. has a surplus of dairy. Last May the U.S. had enough surplus cheese to supply each person in the country with three pounds. Revenues for U.S. dairy producers have dropped 35 percent over the past two years and to help out the USDA is buying $20 million of cheddar cheese. The cheese is donated to school lunch programs, food banks, and other assistance programs but the cheese begins in the photo below. The water and wetlands used aren’t being reimbursed.
Do we want this?
Or this?
I don’t think we can have both unregulated agricultural production with unsound water use policies AND healthy ecosystems. I’m willing to eat fewer almonds and send the water savings to the wildlife refuges, to the rivers and streams needed by salmon. My dairy intake is miniscule and I could give it up tomorrow (oh buttery croissants, I’ll miss you!). But my personal choices are not affecting the problem. We need better agriculture and water management policies and fewer nuts.
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