Improved Water Efficiency Paramount to Future of California Farmers, Officials Say

It is dif­fi­cult to over­state how impor­tant California is to United States agri­cul­ture.

According to the 2023 Feeding the Economy report, nearly 13 per­cent – $1.1 tril­lion (€1.0 tril­lion) – of the United States’ agri­cul­tural out­put comes from California.

The Golden State is the largest agri­cul­tural pro­ducer in the U.S. by a wide mar­gin. Texas and New York, sec­ond and third, com­bine to pro­duce as much agri­cul­tural out­put as California.

The state is also respon­si­ble for vir­tu­ally all U.S. olive oil pro­duc­tion, with the California Olive Oil Council, a trade asso­ci­a­tion, esti­mat­ing that the Golden State pro­duces between two and four mil­lion gal­lons (7.5 to 15 mil­lion liters) each year.

As a result, water is top of mind for many farm­ers, includ­ing the state’s olive grow­ers, and an increas­ing point of ten­sion between rural and urban Californians, espe­cially after years of intense drought.

According to the California Department of Water Resources (DWR), agri­cul­ture accounts for approx­i­mately 40 per­cent of the state’s total water use and about 80 per­cent of all devel­oped water, which is con­trolled and man­aged for var­i­ous pur­poses in California.

The state’s wet win­ter has lifted vir­tu­ally all of California out of drought, accord­ing to the U.S. Drought Monitor. Still, offi­cials are wary of improv­ing agri­cul­tural water use effi­ciency to meet the state’s water needs.

“It’s impor­tant to under­stand that all regions in California are vul­ner­a­ble to cli­mate change, and their vul­ner­a­bil­i­ties are often inter­con­nected, includ­ing in agri­cul­ture and water man­age­ment,” Sabrina Cook, DWR’s water use effi­ciency imple­men­ta­tion sec­tion man­ager, told Olive Oil Times.

She said that some of the respon­si­bil­ity for improv­ing water effi­ciency falls on the agri­cul­tural water providers, the largest of whom must sub­mit man­age­ment plans that include a descrip­tion of the best pro­fes­sional prac­tices.

In the fer­tile San Joaquin Valley, which com­prises the south­ern half of the state’s Central Valley, author­i­ties are already tight­en­ing water reg­u­la­tions, which some have spec­u­lated could spur dry­land olive cul­ti­va­tion in the region.

Mike Anderson, a cli­ma­tol­o­gist at DWR, warned that the state’s wet win­ter is the result of cur­rent atmos­pheric con­di­tions and should not be viewed as a long-term reprieve from drought.

“While cli­mate dri­vers like El Niño change weather pat­terns that impact California, each year water sup­ply and flood and drought risk are dri­ven by the tim­ing, pace and scale of atmos­pheric rivers,” Anderson told Olive Oil Times.

He explained that when large storms come close together, the pace is accel­er­ated, and flood­ing tends to occur. On the other hand, drought con­di­tions occur when California misses out on these storms and has more warm, dry days in win­ter.

“Reservoirs and ground­wa­ter pro­vide a buffer to the dry con­di­tions that can hap­pen in a sin­gle dry year,” he said. ​“Multiple dry years tend to lead to greater drought impacts.”

Caitlin Peterson, the asso­ciate direc­tor and a research fel­low at the Public Policy Institute of California’s Water Policy Center, con­firmed that ample win­ter rain­fall alle­vi­ated the drought but warned this may only be a reprieve.

“Thanks to 2023’s impres­sive win­ter and this year’s con­tin­ued rain­fall,” she told Olive Oil Times. ​“This is great news for agri­cul­ture and the state’s water sys­tems.”

However, Peterson added that all indi­ca­tors point towards more fre­quent, longer dry spells and larger swings in inten­sity between peri­ods of drought and rain in California’s future.

“We will con­tinue to get these short burst peri­ods of heavy rain­fall, but droughts are not going away any­time soon,” she said. ​“We need always to be plan­ning for the next drought, even when it’s cur­rently rain­ing out­side.”

As California braces for more rain, the ques­tion arises whether this helps refill aquifers, reser­voirs and water basins.

“For refill­ing reser­voirs, a high-vol­ume, short-dura­tion storm is as good as any,” Peterson said. ​“Our reser­voirs are in pretty good shape over­all at the moment; all but a few have more water in them than the his­tor­i­cal aver­age for this time of year. That is a stark dif­fer­ence from where we stood in February 2022.”

“Unfortunately, ​‘flashy’ weather events like this are not as help­ful for refill­ing under­ground aquifers,” she added. ​“For recharge to hap­pen, the water needs to have some res­i­dence time, mean­ing it has to hang around for a while so it has time to per­co­late down through the soil.”

When soils are sat­u­rated with water, addi­tional water runs off into water­ways or drainage sys­tems instead of per­co­lat­ing down to the water table.

“Some of this can be stored in our reser­voirs and released later in the sea­son to be used for ground­wa­ter recharge, but this brings its chal­lenges because reser­voir oper­a­tors also have to think about man­ag­ing flood risk, hydropower and ensur­ing enough sup­plies for other pur­poses,” Peterson said.

As rain con­tin­ues to pound the state, con­cerns about poten­tial dam­age arise, with some wor­ry­ing that high-vol­ume, short-inter­val storms cre­ate more dam­age to the infra­struc­ture and crops than pro­vide help.

“As California sees more pre­cip­i­ta­tion falling in shorter, more intense peri­ods, DWR is work­ing with fed­eral, state and local part­ners to col­lab­o­rate and coor­di­nate oppor­tu­ni­ties to enhance ground­wa­ter recharge when the larger storms come through and update reser­voir oper­a­tions,” Anderson said.

“This pat­tern of more punc­tu­ated storms sep­a­rated by warm spells will become more com­mon dur­ing our wet sea­son,” he added. ​“Flood impacts to infra­struc­ture and crops depend on ​“the tim­ing, pace and scale of atmos­pheric river storms.”

Bekele Temesgen, a land and water use sci­en­tist at DWR, believes that edu­ca­tion is crit­i­cal to improv­ing water use effi­ciency among the state’s farm­ers and empha­sizes the use of free tools such as the California Irrigation Management Information System (CIMIS).

CIMIS is a net­work of auto­mated agro-cli­matic weather sta­tions that col­lect weather data, such as solar radi­a­tion, air tem­per­a­ture, wind speed and rel­a­tive humid­ity and cal­cu­late ref­er­ence evap­o­tran­spi­ra­tion.

Temesgen said CIMIS helps farm­ers save water, energy and money by inform­ing them to apply the right amount of water at the right time.

“A recent study by the University of California – Berkeley found using CIMIS data saves at least five mil­lion acre-feet (six bil­lion cubic meters) of water per year in agri­cul­ture,” Temesgen told Olive Oil Times. ​“This trans­lates to a mon­e­tary sav­ing of at least $1.5 bil­lion (€1.4 bil­lion) in urban water costs for land­scape irri­ga­tion.”

“In addi­tion to these sav­ings, using the right amount of water at the right time will improve envi­ron­men­tal health by reduc­ing sur­face runoff and deep per­co­la­tion of con­t­a­m­i­nated water and help us mit­i­gate the impacts of cli­mate change through reduc­ing energy use,” he added.

According to Temesgen, the data col­lected by CIMIS allows olive farm­ers to deter­mine the crop water require­ments. This can be done by mul­ti­ply­ing ref­er­ence evap­o­tran­spi­ra­tion by the crop coef­fi­cient for olives avail­able on the web­site.

Additionally, the state offers a series of grants to agri­cul­tural com­pa­nies, includ­ing olive farm­ers, for invest­ments in water-sav­ing and effi­cient-use projects. Among these is a $23.3 mil­lion (€21.7 mil­lion) pro­gram offer­ing grants to grow­ers who limit agri­cul­tural water use.

Cook said that so far, six of these grants cov­er­ing 4,317 acres (1,747 hectares) of land had been awarded, ​“per­ma­nently reduc­ing demand on California’s aquifers while remain­ing avail­able for flood pro­tec­tion, active ground­wa­ter recharge and sus­tain­able local farm­ing.”