Why California Can Have Healthy Farming Even as Water Supply Diminshes

By Peter Gleick, Pacific Institute. Posted July 27, 2009.

The Pacific Institute has just released a major new study that shows that a strong and healthy California agricultural sector can flourish despite diminishing water supply and future uncertainty from climate change, but only if new steps are taken to significantly increase the efficiency of water use in California fields. The good news is that many farmers and irrigation districts are already making improvements in how they use water. The better news is that there is still tremendous untapped potential - potential that totals millions of acre-feet. The report also offers explicit policy and water management changes to capture this potential.

The new report, Sustaining California Agriculture in an Uncertain Future (funded by the David and Lucile Packard Foundation and the William and Flora Hewlett Foundation), quantifies the potential to reduce agricultural water withdrawals and vulnerability to drought and climate change while maintaining and even increasing productivity.

Water Number: 4.5 to 6 million. The number of acre feet each year that we estimate can be saved statewide by comprehensive changes in the irrigation technologies and management practices we use to grow California's crops. This savings represents around 17% of all of the water used by agriculture in California. In comparison, this is 19 times the amount of water returned to the environment through the recent Delta smelt ruling.

While there are many approaches to increasing our water-use efficiency, we looked at three: improving irrigation and soil moisture management, changing from old inefficient irrigation technology to newer efficient technologies, and regulated deficit irrigation.

Pacific Institute

Potential water savings (in million acre-feet) in a wet, average, and dry year

Our report finds that all three of these approaches show potential for significant savings. Indeed, all three are already being implemented by innovative farmers. Many farmers have worked hard to improve water-use efficiency in recent years, but much more can be done. For example, an astounding 58% of crops are still irrigated in California by flooding the field - a practice that leads to unproductive water loss. As hard as it is to believe, the last irrigation survey in California showed that nearly 300,000 acres of vineyards are still grown using flood irrigation in the San Joaquin and Tulare hydrologic regions (as are many more acres of crops that don't need flood irrigation). In comparison, fewer than 4,000 acres of vineyards in the rest of the state are grown using flood irrigation. Converting even a fraction of flood irrigation to sprinklers allows farmers to apply water with greater precision and uniformity, boosting yields and quality, while reducing unproductive water use. Other states already do far more with smart irrigation systems than California.

See more stories tagged with: water, california, drought, water scarcity, water shortage

Dr. Peter Gleick is president of the Pacific Institute, an internationally recognized water expert and a MacArthur Fellow.

Liked this story? Get top stories in your inbox each week from Water! Sign up now »