California is a Diverse Agricultural Powerhouse – BUT has a Severe Lack of Water

A map of California of which the Central Valley can be seen by the green shaded area.


Visit Date: Tuesday 29th March 2016
Location: Fresno, California

Our visit to California has primarily been located around Fresno, a city situated within the heart of the state’s agricultural powerhouse known as the ‘central valley’, a huge flat plain that dominates the geographical centre of the state. It is approximately 40 to 60 miles wide and stretches approximately 450 miles from north/ northwest to south/ southeast, inland from and parallel to the Pacific Ocean. In total, it covers around 22,500 square miles, about 13% of California’s total area.

The central valley is one of the most agriculturally productive areas of the world with over 300 different types of crops grown. On less than 1% of the total farmland in the US, the central valley produces approximately 15% of the nation’s agricultural output.

The central valley’s watershed comprises of approximately 60,000 square miles of land, being over a third of California’s land area. Its three main drainage systems are the Sacramento Valley in the north, the drier San Joaquin Valley in the south, and the Tulare Basin in the southernmost end. The Sacramento and San Joaquin river systems drain their respective valleys into the ‘Sacramento – San Joaquin River Delta’, a large expanse of canals, stream beds and salt marshes, which empty into the San Francisco Bay.

The whole of the Central Valley flows into the Delta, and then out into San Francisco Bay



The lack of water is a huge problem in California and to look into this issue we spent a morning with Westlands Water District and listened to a presentation given by Ara Azhderian, a Water Policy Administrator within the state.

Presentation to our Nuffield Group by Ara Azhderian – Water Policy Administrator


Good quote by J F Kennedy


California relies on an elaborate network of water storage and delivery systems to supply water to agricultural land. In an average year (not in a drought year as the state is currently experiencing), nature provides about 200 million acre-feet of precipitation. Of this, about 65% is lost through evaporation and transpiration by trees and other vegetation. More than 30% flows directly into the Pacific Ocean, and the rest is captured and utilised for agriculture, urban and environmental purposes.

Irrigation is essential, and to irrigate more than 9 million acres of crops, farmers use about 40% of the State’s available water on irrigation, compared with around 10% used in cities. The remaining 50% is categorised as ‘environmental water’ and regulated so as not to be used for any other purpose. Environmental Water is that within rivers protected as ‘wild and scenic’ under federal state laws, water required for maintaining habitat streams and water that supports wetlands and wildlife preserves .

Coupled with a lack of natural supply, California faces huge challenges in moving water around the state, as about 75% of the annual precipitation falls north of the state’s capital, in the Sacramento Valley, while more than 75% of the demand for water is in the south, within the San Joaquin Valley. The state also relies on good snow fall occurring between October and April, however this isn’t always guaranteed.

California’s water system was developed to address such a mismatch with seven major systems of aqueducts and associated infrastructure being constructed, capturing water and delivering it across the state. Two of the most important projects are the federal Central Valley Project (CVP) and the State Water Project (SWP). The CVP and SWP bring water from northern California through the Sacramento- San Joaquin River Delta for delivery to users in the San Joaquin Valley and southern California.

  • The CVP delivers around 1 million acre-feet per year, and was constructed in the 1930’s to 1950’s.
  • The SWP delivers around 2.3 million acre-feet per year and was constructed in the 1960’s to early 70s.

Local water districts such as Westlands Water play an important role in delivering water to California’s communities and agricultural land. Some purchase water from the major state and federal projects, treat the water as needed and deliver it to their customers.

Westlands Water District is located within the southern part of the central valley, and comprises of some 600,000 acres of productive farmland. More than 60% of the Districts area is producing fruits and vegetables as well as permanent crops such as almonds, pistachios and grapes.

Dry surface water channel on a farm within the Westlands Water District


Saline conditions within the Westlands region is becoming an increasing problem. In many parts of the District, high levels of salts are accumulating in the soil from imported irrigated water. Without proper drainage and disposal, this saline water can impact the root zones of plants, preventing crop growth and reduces yields. To address this problem, in the late 1970’s Congress ordered through statue the construction of appropriate drainage facilities, however these were shut down due to unforeseen impacts on wildfowl from the naturally occurring element, selenium, in the drainage water. Regulations are heavily weighted in favour of environmental protection and habitat conservation. Surface water supply has been limited in certain areas to protect a small fish species, such as the ‘Delta Smelt’

This, coupled with the last few years drought has meant that Westlands over the last few years have had to temporarily retire between 30 to 50% of the land within the District (180,000 to 300,000 acres) from receiving any water allocation. Understandably, there is a strong feeling amongst the farming community that regulation is weighted to heavily on wildlife conservation, rather than food production. It is true that

“Food only grows where water flows”

and as such, unless the farms which have been retired from water allocation have their own bore holes, they have dried up and become unproductive.

A farm located within the Westlands Water District that has recently installed a bore hole well to help secure water supply.



The cost of water forms a vital part of every farms annual budgeting. To receive surface water, first, one must own water rights which specify their allocation. Then if available, that allocation must be purchased. The price of water is increasing, with prices varying from around $1,300 per acre foot at present and rising to $2,000 per acre foot for next year’s supply. Margins are getting tighter and more technologies are being advanced to reduce on farm water use.

IN SUMMARY, better technologies need to be adopted to reduce water use and wastage, such as;

  • Greater adoption of drip irrigation systems
  • Better lined channels for transporting water
  • Automatic systems that use water more intelligently.
  • Reuse and recycling systems
Land being prepared for tomato planting which will be drip irrigated


Concrete channel filled with water from borehole


The following also needs to be considered;

  • Better accountability for environmental management actions
  • Regulatory reform that better distinguishes policy from science
  • Need to address scientific uncertainty, especially if as an outcome regulation is overly or unnecessary protective
  • Consolidation and adoption of a streamlined permitting process
  • Broader collaboration sector wide

As California rapidly grows in population to reach an estimated 48 million by 2030 from 39 million in 2015, local and state water managers will need to carefully address the demands of both urban and rural needs to ensure that California has a water supply system that is fit for the future.

Our morning visit to Westlands Water District was a poignant reminder that without water, food will not grow. The central valley produces approximately 15% of the nation’s agricultural output, on 1% of the total US’s farmland area, and therefore finding a solution to the water crisis is paramount.

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