Water in California

What is freshwater to California? To me, it is the delicious water that comes out of the faucet, it is the sorry (but once-upon-a-time, glorious) snowpack in the Sierra Nevada’s, and it is the miles and miles of farms and orchards in the Central Valley. The draught brought a lot of media attention to water usage in California — I looked at the numbers, and this is what I found.

According to a 2010 USGS survey, California draws about 31 billion gallons of freshwater per day. I suspect with the low flows in the rivers and the low groundwater level, this number is quite a bit smaller now.

Lake Tahoe has the capacity to hold…enough freshwater to water California for just a little less than 8 days.

Still, 31 billion gallons is no joke. To put it in perspective, Lake Tahoe has the capacity to hold 239 billion gallons of water — or enough freshwater to water California for a little under 8 days.

Contrary to what one might expect, big cities such as San Francisco and Los Angeles are not the biggest water drinkers in the state.

Daily Freshwater Withdrawn in Million Gallons

This map charts water consumption per county. The deeper the red, the more water is used. As we can see, the top 3 water-consuming counties are all heavily agricultural counties:

1. Fresno County: drew 2,800 million gallons of freshwater a day, or about 9% of the state’s total freshwater in 2010
2. Tulare County: drew 2,600 million gallons of freshwater a day, or 8.4% of the state’s total in 2010
3. Kern Couty: drew 2,000 million gallons of freswater a day, or 6.7% of the state’s total in 2010.

Los Angeles County came in at #6, and drew 1,600 million gallons of freshwater a day (5.2% of the state’s total). San Francisco scraped the bottom of the barrel at #43 (out of 58), and drew only 83 million gallons of water a day.

San Franciscans…are the most water-efficient residents in California — consuming only 52 gallons of freshwater per person a day.

Looking at only domestic consumption of freshwater, I am surprised by the amount of variation there is. San Franciscans will be happy to know that they are the most water-efficient residents in California — consuming only 52 gallons of freshwater a day on average.

Residents of Shasta county, on the other hand, can pride themselves as the most water-hungry residents in California — consuming….wait for it…169 gallons of water a day. Your guess is as good as mine…perhaps Shastans just love bathing.

It is true, 74% of the state’s freshwater is used for irrigation — of this, 1% is used for golf courses and the other 99% is used for crops. Household use accounts for only about 13% of the state’s drawn freshwater. The remaining usage is scattered among industrial, aquaculture (farming fish and plants), and livestock.

What is interesting is that the biggest water guzzler of all crops is — Alfafa. What-fafa? Alfafa alone uses about 15% of the state’s freshwater withdrawn. It is not your usual salad ingredient, in fact, Alfafa is mostly used as forage for cattle and harvested as hay.

Cattle-farming consumes 31.6% of California’s freshwater each year.

Along with Alfalfa, cattle-farming also requires pasture, feed (what most of California’s corn is used for), and water for the animals. All in all, this tallies up to:

...Alfafa: 15% of all freshwater

…Pasture: 10% of all freshwater

…Corn: 6% of all freshwater

…Livestock: 0.6% of all freshwater

…And we come to the whopping conclusion that cattle-farming consumes 31.6% of California’s freshwater each year.

Coming back to crops, the second largest group of water-consuming crop is made up of almonds and pistachios. The production of these two nuts consume about 11% of the state’s total freshwater supply.

Hmm, steak, almond or toilet-flushing? Hard choices.

California is in a draught. It is not to say that the big consumers of water are big bad guys — if anything, this data shows that towns and industries which traditionally rely heavily on an abundance of water are the hardest hit by the draught. The next USGS survey will be illuminating. If water levels do not bounce back to where they were, California’s economy is in for some really big changes.

Tools and Data Sources:

California Department of Water Resources — Irrigation Crop Acres and Water Use

Indiemapper — Link

Souther California Earthquake Center — California Counties Shape File

United States Geological Survey — Water Use in the United States