Tuesday, April 7, 2015

The California Drought

"Whiskey's fer drinkin' - Water's fer fightin'"

Summary:  The main problem with California's drought is that we are not using water wisely in our most intensive areas of water use - agriculture - 77% of our water use.   There has been enormous variation in drought conditions over the last 2,000 years and California's water rights were mainly resolved in one of the wetter of those periods.  It has been drastically over-committed as if one of the wettest periods of the last 2 millenia was normal.  High variation doesn't mean that global warming isn't real. Whether global warming is real or not, doesn't matter.  We need to properly use the water we have.

Since farming uses 77% of California's water (for 1%-2% of CA's GDP), it is of immediate interest.  That  77% means that if agriculture cut down it's use by 5% (= 3.5% of the total water used in CA) the average city dweller would have about 50% more water.  Conversely, if city dwellers stopped all water use right now - perhaps using only desalinated water and "gray water" - farmers would only see 10% more water than they get now.
Water Consumption
(Click to enlarge) SF = Single Family, MF  = Multi-Family
(Graphic from http://www.environment.ucla.edu/reportcard/article4870.html )

CA GDP by Sector
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The 77% figure is of water consumed by people, excluding "environmental" use.  There is a lot of water for environmental purposes (maintaining streams and rivers) but most of that is too remote for use by any farmers, assuming you wanted to dry up every river and stream for agriculture.  Even as the population grows, urban water use is holding steady.

Above from http://www.ppic.org/main/publication_show.asp?i=1108

(Some of the following from NY Times)

CA's agriculture has 3 million acres now using drip irrigation.  But, 4 million acres are irrigated by flooding which is extremely wasteful.  In 1991 15% were drip irrigated but by 2010 that was 38%.  The 70% that was irrigated by flooding in 1991 is now down to 43%, but it could go much lower.

Of the acreage used for farming in CA, 2 million acres had their water supply cut to zero and another 1 million acres had their supply cut to 5%.  So they are draining aquifers (underground stored water from previous rainfall) which is expensive and unsustainable  At the same time they are moving towards more efficient watering methods.

An enormous amount of water goes to growing almonds and pistachios, 67% of which is for export. More water was allocated than can possibly be delivered.  The CA and Federal govt. should buy out and retire the water rights that should never have been promised.

(Click to enlarge)

The New York Times has a fascinating article showing how much water common foods use here:

The single largest water use in CA is for alfalfa for cows.  Some of this alfalfa is exported to other countries like Japan and China for their cows.

All cows in CA consume 10 million Acre-feet of water in a year.  All the people in CA consume 8 million acre-feet per year.  Other parts of the US (like Wisconsin, Iowa) can grow alfalfa and cows as well as CA. From: http://www.bloombergview.com/articles/2015-04-13/cows-suck-up-more-of-california-s-water-than-almonds

The US shouldn't be so dependent on CA for fruits and veggies.  Iowa could switch just one county's worth of land from growing corn to fruits and veggies and supply most of the mid-west - and make more money doing it than they do growing corn.  The reason they haven't grown more fruits and vegetables in the mid-west is largely tradition but also that it takes more labor to grow and harvest fruit and vegetables.  With a little education in different farming techniques, farmers can switch crops.  With tobacco subsidies gone, N. Carolina is turning to growing healthy foods like apples.

"Dry Farming" techniques can make now fallow fields grow gourmet tomatoes, figs, almonds, etc.
"Dry farming" is showing great success in CA as a way to make best use of limited water.  Tomatoes grown this way look a little shriveled but with very rich taste so calls come in from around the country from gourmet restaurants for them.  Figs, apricots, olives, walnuts and almonds have all been grown that way in Europe and Northern Africa.  "In some places in southern France it’s illegal to irrigate because it changes the quality of the wine".  C.f. "Modern Farmer":

Dependence on CA for so much food is not in the best interests of the country.  Food has to be trucked thousands of miles burning gas and adding expense. More mid-western farmers are thinking of growing vegetables since there is a demand for fresh vegetables that haven't traveled thousands of miles by truck and lost their taste and nutrients.  More here:

(Click to enlarge)
CA grows 82% of the world's almonds.  44% more land is used for almonds in CA than was used 10 years ago.  "thousands of endangered king salmon in northern California’s Klamath River are threatened by low water levels because water is being diverted to almond farms."  It is hard to justify so much water for almonds and walnuts used mainly as a snack or garnish.  Endangered salmon going extinct to supply almond croissants and chocolate-walnut muffins?  Other parts of the world could grow almonds and walnuts - almonds originally came from the Middle East.  England is starting to grow some now.

Last year CA passed legislation that would require, for the first time, tracking how much water is drained from aquifers.  But the time limit legislated to get to sustainable withdrawals is 20 years.  The aquifers are being drained to the point they may not recover since once an aquifer is drained the ground compresses and it is not always possible to reconstitute the aquifer after compression.

In Santa Clara County, the draining of the aquifers resulted in a 13 foot subsidence of the land.  As a result, some of Santa Clara and Sunnyvale is now below sea level and needs to be protected by levees. The following three graphics are from the Santa Clara Valley Water District's  Protection and Augmentation of Water Supplies 2014/2015 at http://www.valleywater.org/Publications.aspx The SCWD is the "wholesaler" to local districts which supply the water to individuals.  The local districts determine local pricing.
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The following chart (from the same SCWD publication) suggests if every user could cut their water use by 25% - perhaps by using CA drought tolerant plants for their front yards - we could make a massive difference in how much water is used in Santa Clara County.
Ag = Agriculture, M&I = Municipal and Industrial
An interactive map of water use by town or district shows wide variation of who uses how much.  Sunnyvale uses 52 Gal/person per day (G/P/D), San Francisco uses 45 G/P/D, Coachella Valley in S. California - a retirement community - uses 238 G/P/D
(Click to enlarge)
Above photo from http://www.nytimes.com/2015/04/05/us/california-drought-tests-history-of-endless-growth.html

There is a huge variation in water use in populated districts during the year with Winter the lowest usage period and Summer the highest.  During the Winter, there is very little difference in water usage between high density areas and low density areas.  Sunnyvale vs San Francisco shows what happens when landscaping takes more water and the temperatures are warmer (causing faster evaporation).  Sacramento shows what happens when you don't meter water usage.

2014 Water Use Gallons/Person/Day
July: Sacramento:   159    Dec: Sacramento:     63
         Sunnyvale:       91             Sunnyvale:      44
         San Francisco  46             San Francisco  40

Above data from "June 2014 - February 2015 Urban Water Supplier Report" Excel spread sheet downloaded from:

There are 15,000 desalination plants in the world and several big new ones are being built in California.  Desalinated water is roughly two times as expensive as current urban prices for water.

Israel has essentially solved it's perennial water shortage with desalination and recycling: http://www.nytimes.com/2015/05/30/world/middleeast/water-revolution-in-israel-overcomes-any-threat-of-drought.html#

Global Warming Cause?
The drought is hard to directly connect to global warming since there has been enormous variation over the centuries in dry-wet cycles but the drought has been made worse because when rain does fall it evaporates more quickly.

Some scientists do see links as here:

and here:

Others don't:

Some who are in the middle:

From last link above: "Bond says that although the blob does not seem to be caused by climate change, it has many of the same effects for West Coast weather."

For a little "drought & global warming" humor try this:

Does it matter?  If global warming is the cause, we aren't about to reverse global warming in a few years so we need to make better use of our water resources from now on.  If natural variation is the cause, we can't do much about it and need to make better use of our water resources from now on.  Same result either way.

Historical Variation:
From the charts below you can see enormous variation in the drought cycles.  The first chart shows that the period from 1800 to 2000 was the wettest since the years 600-700.

(Click to enlarge)
Above chart from http://www.ncdc.noaa.gov/paleo/ctl/cliihis1000a.html

The next charts show that the area in drought was far more extensive in the period 800-1300 than any time since.  We are possibly coming off an extended period of a relatively small area in drought.
(Click to enlarge)

The next chart shows that there have been periods of extended drought far longer than we have experienced in the last 50 years.  The difference is that there were far fewer people in the southwestern US then.
(Click to enlarge)

A paper in the Proceedings of the National Academy of Sciences (PNAS) attributes 52% of the drought to the normal Pacific and Atlantic oscillations and 22% to a warming in the northern hemisphere.

A simulation of a long (72-year) drought similar to those in the past with CA getting 50% of the average water supply was done.  It found that agriculture would suffer a potential decline of about 50% in land area but that water trading schemes would enable CA overall to manage to get through it if it managed it well.

It may seem as if I am placing all the blame on agriculture.  Well, they use 77% of the water so they get 77% of the blame.  But we all get some of the blame.  We all need to do our part.  For our own self respect, if nothing else.  Claiming we don't have to do much because someone else could do more isn't going to fix the situation.  We are in a dry climate and should act like it, respecting the resources we have.

1 comment:

  1. What a novel concept. "The CA and Federal govt. should buy out and retire the water rights that should never have been promised."