Feb 9 2014
California reservoirs are as low as they have been in a decade. See this article in the Terra Daily.
To understand the above graphic which is set up in cubic kilometers of
water, consider the following outtake found in www.water-shock.com that
explains how much water in cubic kilometers there is. This is not in the published book. Only in the Excerpts tab on the site.
Charlie Reagan explains to Arnie Jones on the way to San Diego how much
water there is in the world and what the demand is now and may be in the
“Youre an engineer, so I can talk in figures, he says and lays out
the numbers. People can capture only a fraction of the freshwater runoff and infiltration of 41,000 cubic kilometers per year. Of the 28,000 cubic
kilometers per year of flood runoff, the usable portion depends on the
capacity of human-made dams and lakes and how often the water in such
reservoirs is turned over.”
“The world’s available renewable freshwater lies somewhere between the 9,000 cubic kilometers per year of stable underground flow in inhabited regions and the 14,000 cubic kilometers per year if the stable underground flow in inhabited regions is included, plus the usable capacity in human-made reservoirs[i]. That figure is around 10,000 cubic kilometers . . . To be conservative,” Charlie adds.
“Hold it a minute, “Arnie says. I dont have a clue about the cubic
kilometers of water. Help me out.
“Okay, try this”, Charlie says and explains that there are 325,900 gallons
in an acre-foot, which will supply two families of four for a year in the
United States. Okay?
“So one family uses about a hundred sixty-three thousand gallons per year.
“Got it, half an acre-foot, Arnie says, pointing out that per person its
about 41,000 gallons per year”.
“Yes,” Charlie says.” Now, we know the U.S. figures are high compared to the rest of the world, so lets cut that number to ten thousand gallons per year per person. Still with me?”
Charlie runs more numbers by Arnie, saying there are an estimated 12 billion people on the planet. Multiplying 10,000 gallons per year per person times 12 billion is a big number120 trillion gallons on the demand side. On the supply side, there are 10,000 cubic kilometers of freshwater available, not evenly distributed. So 10,000 cubic kilometers times 850,000 acre-foot per cubic kilometer times 326,000 gallons in an acre-foot is also a big
number2,800 trillion gallons.
Charlie glances at his listener to see if he still has an audience. Arnie looks over, saying, So?
“So, in the same reference, there is an appendix that gives estimates of
past human population sizes worldwide. In 1900, there were about
one-point-six billion people on the earth. By 1990 there were just over five
billion, with the expectation that the worlds population would grow by a
billion every decade. The last accurate count we have is 2060, and they were right. Twelve billion people now depend on the same nine thousand to
fourteen cubic kilometers of freshwater. Thats why I used the twelve
billion population number.
“So, thats all there is, no matter how many people we put on this planet?”
Milton N. Burgess, P. E., FASPE
Author of Water Shock, The Day Southern California Went Dry