While California is the agricultural hub of the United States, limited rainfall makes farming tricky. While forecasting future rainfall is a shaky business, a turn towards California’s hydrological history might be useful to understand the possible climate and water availability scenarios the state might encounter.
California’s Hydrological History Sheds Light on Possible Future Climate and Precipitation Scenarios
The weekend storm that dumped heavy rainfall from the Bay Area to Los Angeles gave the state much needed relief from the crippling and widespread drought even if there wasn’t nearly enough precipitation to end it.
The substantial rain is more than welcome, but it’s cold comfort for many hard-hit farmers across the drought-stricken state who are imagining what the future holds for their still-parched fields and orchards.
While forecasting future rainfall is a shaky business, a turn towards California’s hydrological history might be useful to understand the possible climate and water availability scenarios the state might encounter.
As it stands, California is one of the world’s great agricultural hubs and the top food producer for the United States in terms of economic value, growing more than 80 percent of the country’s artichokes, celery, broccoli, cauliflower, strawberries, almonds and walnuts, among other high-value crops. California’s tremendous agricultural productivity depends on its fertile soil, its sunny climate and abundant water. That third vital element is not native to many of California’s semi-arid agricultural regions, so Golden State farming relies almost exclusively on irrigation water for its survival – and an enormous quantity at that – with just under 80 percent of all surface and groundwater withdrawals in the state going to agriculture. (Groundwater levels are plunging because of over-pumping.) The situation looks particularly dire for farmers as the federal government took the unprecedented step of severely reducing irrigation water allocations from the Central Valley Water Project for the remainder of 2014.
Since agriculture predates extensive irrigation projects, an enquiry into California’s farming history might be worthy. Step back to the environs of Manteca in the San Joaquin Valley, now home to the cultivation of melons, pumpkins, almonds and grapes. Before irrigation could sustain these water-intensive crops, wheat farming drew Gold Rush-era settlers to the area.
The [wheat] crop started appearing in the area in 1850. It was about the only viable crop for several reasons. First there was no irrigation. Developed markets were thousands of miles away. There were also two basic soil choices—adobe which retains moisture but is impassable during winter and sandy loam that can be farmed year-round … [By] 1880 San Joaquin County raised the fifth largest wheat crop in the world.
Wheat farming stood strong after the cattle ranching industry, which began to dominate the Valley, crashed after a serious drought in the mid-1860s. But everything changed when the South San Joaquin Irrigation District was formed and began providing irrigation water and the ability to produce the thirstier crops grown today.
Looking further into California’s past, the climate and water availability picture becomes even starker. The state’s climatological history is replete with “megadroughts” that lasted for decades and two that each lasted for over century, as UC-Berkeley professor, Lynn Ingram, recounts in her book The West Without Water. To compound the problem, the tremendous growth in California’s population as well as its economic, agricultural and water infrastructure development all occurred in the 20th century, one of the state’s four wettest centuries in the past 7,000 years (paywall). Simply put, the expected volume of water that supports California’s current demand may not be there in the future, a deep concern for agriculture, the largest water user.
No one knows for certain whether the California drought will persist or if drier times lie ahead and what that might mean for irrigation water allocations. Certainly we can expect irrigation water to continue to play a role in the agricultural landscape, but this drought has farmers making tough choices that have ramifications for the future about what crops to plant (water intensive vs. drought tolerant), what farmland to lay fallow and the viability of continuing to rely so heavily on water from other places. Who knows, the next few years could bring great rains and build the Sierra Nevada Mountain snowpack. If it doesn’t, there will be more difficult choices ahead.
Californians will debate the merits of the Bay Delta Conservation Plan or might look abroad to how desperate Australian farmers are coping in a water-scarce environment, or they could look to their past. Undoubtedly climate change is exacerbating the current drought and will likely destabilize the water cycle because higher temperatures give rise to higher evaporation rates. Nonetheless, the last few years has brought much talk of drought and water shortages becoming the “new normal,” but maybe by recognizing the current experience in California and much of the West as a reflection of the past we may come to see the situation as a return to “normal.”
Originally published at GRACE’s former blog Ecocentric by Kai Olson-Sawyer on 3.3.2014.
Image: Center Pivot Sprinklers by AgriLife Today on Flickr