JUST IN: UC Davis’ Preliminary Findings on Drought Impact in Central Valley

Source Office of Public Affairs

Photo Source-Aquafornia

California’s drought impact will be a severe blow to Central Valley irrigated agriculture and farm communities this year and could cost the industry $1.7 billion and cause more than 14,500 workers to lose their jobs, according to preliminary results of a new study by the UC Davis Center for Watershed Sciences.

Researchers estimated that Central Valley irrigators would receive only two-thirds of their normal river water deliveries this year because of the drought.

The preliminary analysis represents the first socio-economic forecast of this year’s drought, said lead author Richard Howitt, a UC Davis professor emeritus of agricultural and resource economics.

“We wanted to provide a foundation for state agricultural and water policymakers to understand the drought impact on farmers and farm communities,” Howitt said.

The Central Valley is the richest food-producing region in the world. Much of the nation’s fresh fruits, nuts and vegetables are grown on the region’s 7 million acres of irrigated farmland.

The center plans to release a more comprehensive report of the drought’s economic impact on the state’s irrigated agriculture this summer.

The analysis was done at the request of the California Department of Food and Agriculture, which co-funded the research, along with the University of California.

“These estimates will help the state better understand the economic impacts of the drought, ” said CDFA Secretary Karen Ross. “The research confirms where emergency drought assistance will be needed most, and efforts are already underway.”

The UC Davis researchers used computer models and the latest estimates of State Water Project, the federal Central Valley Project and local water deliveries, plus groundwater pumping capacities to forecast the economic effects of this year’s drought.

The analysis predicted several severe impacts for the current growing season, including:

▪Reduced surface water deliveries of 6.5 million acre-feet of water, or 32.5 percent of normal water use by Central Valley growers. An acre-foot is enough water to cover an acre of land in a foot of water, or enough water for about two California households for a year.

▪ Fallowing of an additional 410,000 acres, representing 6 percent of irrigated cropland in the Central Valley.

▪ The loss of an estimated 14,500 seasonal and full-time jobs. About 6,400 of these jobs are directly involved in crop production.

▪ A total cost of $1.7 billion to the Central Valley’s irrigated farm industry this year, including about $450 million in additional costs of groundwater pumping.

▪ About 60 percent of the economic losses will occur in the San Joaquin Valley and Tulare Lake Basin.

Growers are expected to replace much of the loss in project water deliveries with groundwater, California’s largest source of water storage during drought years, said co-author Jay Lund, director of the Center for Watershed Sciences and a UC Davis professor of civil and environmental engineering.

“Without access to groundwater, this year’s drought would be truly devastating to farms and cities throughout California,” Lund said.

The additional pumping will cost an estimated $450 million and still leave a shortage of 1.5 million acre-feet of irrigation water, about 7.5 percent of normal irrigation water use in the Central Valley, according to the forecast.

While the current drought is expected to impose major hardships on many farmers, small communities and the environment, it should not threaten California’s overall economy, Lund said.

Agriculture today accounts for less than 3 percent of the state’s $1.9 trillion a year gross domestic product.Other authors on the report are UC Davis agricultural economist Josue Medellin-Azuara and Duncan MacEwan of the ERA Economic consulting firm in Davis.

Q&A Drought Management For Almonds

Source: David Doll 

These questions and answers offer insightful advice for almond farmers coping with the drought.

Q. How should I plan to irrigate my trees?

A. As discussed before, this is dependent upon the amount of water that is available. If you have greater than 80-85% of the water that is typically applied to the orchard, deficits can be targeted (50% reduction in applied water) for the period after kernel fill but before hull split. If less than 80%, the water should be spread out at the relative percentage of water use. For example, if 30% of the seasons water is available, every irrigation would be 30% of normal. Keep in mind that in drought years it is often hotter than in “normal” years.

Q. When should I start irrigating?

A. Typically, irrigations should start when the trees are starting to “work” for water. Using a pressure bomb, this value is around 2 bars more negative than baseline. If baseline is -8, irrigation should begin at -10.  If facing a moderate curtailment, it may be best to let the trees stress a little more, perhaps -4 bars more than baseline. If facing a severe curtailment, a scenario in which we know less about, it might be best to hold off longer before applying the water (~6-8 bars more negative than baseline, perhaps?). Basically, the idea is to stress the trees, which then triggers a physiological response which makes the tree more drought resistant (less vegetative growth, fewer stomatal openings/leaf, etc).

Q.  What’s an easy way to calculate baseline?

A. To get in the ballpark, baseline can be estimated by taking one tenth of the temperature. If it is 85 degrees, baseline will be -8.5. Since it is measured as pressure applied, it is always read as a negative value. For more specific calculations, which take into account humidity and temperature, please see this UC Davis Baseline website.

Q. How much should I reduce my nitrogen if I am reducing my water?

A. Good question. Nitrogen rates should be reduced. Based upon some speculation from various trial results, our best guess is to reduce nitrogen rates by about 1/2 of the water curtailment. So, if taking a 50% water reduction, nitrogen should be reduced by a minimum of 25%. In-season estimate of crop may also determine that less N is needed. If in a second year of deficit irrigation (i.e. 2nd year of drought), the reduction of nitrogen should match the reduction in water (50% water reduction, 50% nitrogen reduction). Keep in mind that applying too much N will flush growth, increasing vegetation, which will require more water.

Q. I hear and saw stories about people pulling trees…should I?

A. If blocks were planned to be cycled out and removed within the next few years, water from these blocks should be considered to be diverted to other, younger blocks. This will help negate the effects on the developing block. Depending upon where the orchard is located, there may be some crop that is salvageable from the “dry-land” farmed block, but it will be of lower quality.

Q. Are there any other resources to help?

A. Yes – Please see UC Davis’s Drought Management Website for more drought management in multiple crops. To gain a little more help in scheduling irrigation, check out Fresno State’s Water Right Website. Farm Advisor Blake Sanden also has some good information at his Kern County Web Page. Also, feel free to contact your local farm advisor.


New Drought Fact Sheet Available

CATThe California Farm Water Coalition has a brand new fact sheet available on California’s 2014 drought.
The one-page information piece is intended for consumers and breaks down the drought into easy-to-understand sections.
Information includes an updated number of acres expected to be idled this year (800,000 acres), how lost farm production will impact the economy, what consumers can expect to see in stores in the way of food-related price increases and also what farmers have been doing over the years to improve water use efficiency.
The California Farm Water Coalition was formed in 1989 in the midst of a six-year drought. CFWC was formed to increase public awareness of agriculture’s efficient use of water and promote the industry’s environmental sensitivity regarding water.