The Big Thirst, page 40
10. Water: H2O = Life, American Museum of Natural History. http://www.amnh.org/exhibitions/water/.
Having read the observation that a particular cloud doesn’t usually last more than an hour, I’ve begun to watch clouds differently. In watching a single cloud for just a few minutes many times, I’ve seen what I never noticed before, that clouds are more dynamic than we realize, and that their shapes are almost never static.
11. “Rain: A Valuable Resource,” Water Science for Schools, USGS. http://ga.water.usgs.gov/edu/earthrain.html.
12. Biological water volume is listed in the USGS Water Cycle Web site chart. http://ga.water.usgs.gov/edu/watercyclesummary.html.
The volume of the Great Lakes is here:
Great Lakes Fact Sheet, EPA. http://www.epa.gov/greatlakes/factsheet.html.
13. The math on the human proportion of biological water works like this.
If, for purposes of a rough estimate, we say that the average person on the planet weighs 80 pounds—including men, women, and children—and that the average person contains 57.5 percent water, then the average person contains:
80 pounds × .575 = 46 pounds of water = 5.5 gallons.
With 6.9 billion people, that’s 38 billion gallons of water contained inside people.
In terms of the average weight of a person, 30 percent of the people in the world are under the age of 15.
2008 World Population Data Sheet, Population Reference Bureau, Washington, DC, 2008 (PDF). http://www.prb.org/pdf08/08WPDS_Eng.pdf.
14. Igor Shiklomanov, who was born in 1939, is director of the Russian State Hydrological Institute in St. Petersburg and a regular member of international scientific panels, including the Intergovernmental Panel on Climate Change. He did not reply to numerous e-mail inquiries requesting an interview.
A brief biography is here, from the UNESCO International Hydrological Programme. http://www.unesco.org/water/ihp/cvshiklomanov.shtml.
His original chart, “Water Reserves on the Earth,” is in Peter H. Gleick, ed., Water in Crisis (USA: Oxford University Press, 1993), p. 13.
15. The world’s deepest borehole was drilled in the Kola Peninsula, near Finland, as a research effort by the Soviet Union between 1970 and 1994, and reached 12,262 meters. The peninsula is still part of Russia.
Pamela J. W. Gore, The Interior of the Earth, Georgia Perimeter College. http://facstaff.gpc.edu/~pgore/geology/geo101/interior.htm.
16. The title of the world’s deepest mine passed in 2008 to South Africa’s TauTona gold mine, owned by AngloGold. The mine is 3.9 km deep; the deepest tunnels require air conditioning to make mining possible, bringing the air temperature down from 131°F to 82°F. The working rock face at TauTona is 140°F.
TauTona, Anglo Gold, South Africa, Mining-Technology.com. http://www.mining-technology.com/projects/tautona_goldmine/.
17. Don Murray, “Percy Spencer and His Itch to Know,” Reader’s Digest, August 1958, p. 114. http://www.softslide.com/volumes/v2/t3/history/readers_digest.htm.
“Percy Spencer, Inventor, Dead; Retired Raytheon Executive, 76,” New York Times, September 8, 1970.
18. Murray, “Percy Spencer and His Itch to Know,” p. 114.
Percy Spencer’s grandson, George (Rod) Spencer, confirms the details of his grandfather’s discovery of microwaves’ cooking ability in an e-mail exchange. Although many accounts report that Spencer was carrying a chocolate candy bar, Rod Spencer says it was a peanut cluster bar.
19. Of the 130 patents Percy Spencer was awarded, the one for microwave cooking is No. 2,495,429, Method of Treating Foodstuffs. It is just 2½ pages long, and one of them is a simple, full-page diagram. It’s not clear why Spencer used the word “treating” in the title—50 years later, people worry that microwave ovens can somehow “irradiate” them; in fact, they produce no radioactivity, inside or out. But Spencer corrects himself in the patent’s opening sentence: “My present invention relates to the treatment of foodstuffs, and more particularly to the cooking thereof through the use of electromagnetic energy.”
Percy L. Spencer, Method of Treating Foodstuffs, U.S. Patent No. 2,495,429, October 8, 1945. http://www.google.com/patents?id=x_tuAAAAEBAJ.
The U.S. Census provides figures on the number of appliances in U.S. homes. The latest data, released in November 2009, show 96.4 percent of all homes have a microwave, 90.6 percent have a landline telephone, 67.1 percent have a computer.
“Homes with Cell Phones Nearly Double in First Half of Decade,” U.S. Census, November 19, 2009. http://www.census.gov/newsroom/releases/archives/income_wealth/cb09–174.html.
The data tables are here: “Extended Measures of Well-being: Living Conditions in the United States, 2005, Detailed Tables,” U.S. Census. http://www.census.gov/population/www/socdemo/extended-05.html.
The Popcorn Board reports that, as of 2008, Americans bought 966 million pounds of unpopped corn a year—3 pounds for every man, woman, and child in the U.S., the equivalent of 15 regular-size bags of microwave popcorn per person each year. Of that, at least 70 percent is cooked in a microwave.
Industry Facts, Popcorn Board, Chicago. http://www.popcorn.org/EncyclopediaPopcornica/WelcometoPopcornica/IndustryFacts/tabid/108/Default.aspx.
Percentage of U.S. popcorn that is microwave popcorn comes from: Popcorn Profile, Ag Marketing Resource Center, Iowa State University, 2010. http://www.agmrc.org/commodities_products/grains_oilseeds/corn/popcorn_profile.cfm.
20. This elegant—and sticky—metaphor comparing water molecules to socks in a dryer comes from the American Museum of Natural History’s 2007–2008 exhibit Water: H2O = Life. http://www.amnh.org/exhibitions/water.
21. The calculations for how many water molecules would fit in the interior of single red blood cell are rough approximations, but work like this:
A typical red blood cell is:
8 micrometers (μm) long and 2 micrometers (μm) high.
If you simply assume that a red blood cell is a cylinder, its volume is: 3.14 × 16 micrometers × 2 micrometers = 100 micrometers3 (μm3).
100 μm3 = 1 × 10–13 liters.
Now, how many molecules of water are in 1 liter of water?
1 liter = 1,000 grams of water.
(1,000 gm of water) ÷ (18.015 grams / mole of water) =
55.51 moles of water.
55.51 moles of water × 6.022 × 1023 molecules / mole =
3.34 × 1025 molecules of water in one liter.
So in a cell with a volume of 1 × 10–13 liters, the number of molecules is:
(3.34 × 1025 molecules of water/liter) ÷ (1 × 10–13 liters) =
3.34 × 1012 molecules.
So 3.34 trillion water molecules would fit inside a single red blood cell.
22. The comparisons that follow assume a suburban sidewalk that is 3 feet (0.914 meters) wide.
The microchip pathway is 90 nm (nanometers) wide; the sidewalk is 914 million nm wide—10 million times wider than the chip pathway. So each item lying on the chip—on the metaphoric sidewalk—is also 10 million times bigger than life-size.
A human hair is between 50 microns and 150 microns thick (0.00005 to 0.0001 meters)—500 to 1,000 meters in relative terms, between 1,640 and 3,280 feet high across the ordinary sidewalk.
A single red blood cell is about 8 microns wide (8 × 10–6 meters)—80 meters wide on the sidewalk.
A single particle of flu virus is about 130 nanometers long (1.3 × 10–7 meters)—1.3 meters wide on the sidewalk.
A single water molecule is about 275 picometers long (2.75 × 10–10 meters)—about 3 mm on the sidewalk.
Here are two good sites for understanding the relative size of very small objects:
Cell Size and Scale, Learn.Genetics, Genetic Science Learning Center, University of Utah. http://learn.genetics.utah.edu/content/begin/cells/scale.
Exploring the Nanoworld, Intro to Size and Scale, Materials Research Science and Engineering Center, University of Wisconsin Madison. http://mrsec.wisc.edu/Edetc/nanoscale/index.html.
23. Michael Graham Richard, How Many Atoms Encode the Humane Genome? April 6, 2008. http://michaelgr.com/2008/04/06/how-many-atoms-to-encode-the-human-genome/.
3. DOLPHINS IN THE DESERT
1. Las Vegas temperature and precipitation data—72 days a year at 100 degrees or more, 19 days of precipitation—come from the climate data available online from the National Climatic Data Center. Data through 2009—some going back 30 years, some going back more than 50 years—are in:
Comparative Climatic Data for the United States Through 2009, National Climatic Data Center, National Oceanic and Atmospheric Administration (NOAA), Asheville, NC (PDF). http://www1.ncdc.noaa.gov/pub/data/ccd-data/CCD-2009.pdf.
The data for days over 100 degrees come from a slightly older analysis, for Las Vegas specifically, archived here:
Climatography of the United States, No. 20, 1971–2000, Station: Las Vegas, National Climatic Data Center, NOAA, Asheville, NC (PDF). http://cdo.ncdc.noaa.gov/climatenormals/clim20/nv/264436.pdf.
2. What does it mean to say Las Vegas is the driest city in the U.S.?
The National Climate Data Center publication Comparative Climatic Data has data on 274 major U.S. cities and weather reporting stations, going back at least three decades. According to that compilation, the lowest-precipitation cities in the U.S. are Barrow, Alaska; Yuma, Arizona; and Las Vegas. But Yuma and Barrow are small compared with Las Vegas.
Yuma averages 3.01 inches of rain a year, with 16 days of precipitation. The city of Yuma has about 90,000 people, and the larger Yuma metro area has 190,000 people, according to U.S. Census data (2009). Yuma is 1/10th the size of Las Vegas.
Barrow, Alaska, is the only other city with less precipitation than Las Vegas, with 4.16 inches a year, on 74 days a year. Barrow, according to the census, has a population of 4,091 (2009), less than the population in many of the individual hotels on the Las Vegas Strip on a typical night.
Comparative Climatic Data for the United States Through 2009 (PDF). http://www1.ncdc.noaa.gov/pub/data/ccd-data/CCD-2009.pdf.
Annual number of days of precipitation is in a table that begins on p. 37.
Average annual precipitation is in a table that begins on p. 136.
A separate, slightly older analysis of precipitation data from the U.S. Census uses population data from 2000 and precipitation data from 1961 to 1990: “Cities with 100,000 or More Population in 2000 Ranked by Annual Precipitation,” table C-7, County and City Data Book: 2000, U.S. Census Bureau. http://www.census.gov/statab/ccdb/cit7140r.txt.
The U.S. Census list of 280 cities with populations of 100,000 or greater is here. http://www.census.gov/popest/cities/SUB-EST2009.html.
3. Details about Lake Mead’s size and capacity are here:
Hoover Dam: Frequently Asked Questions, U.S. Bureau of Reclamation, Lower Colorado Region. http://www.usbr.gov/lc/hooverdam/faqs/lakefaqs.html.
A list of the largest reservoirs in the U.S., by water capacity, from Stanford University’s civil and environmental engineering department:
Largest U.S. Reservoirs, National Performance of Dams Programs, Department of Civil and Environmental Engineering, Stanford University. http://npdp.stanford.edu/damlarge.html.
A somewhat different list—which still puts Lake Mead at the top—of the largest reservoirs by water capacity, from the U.S. Society on Dams, is here:
“Largest Manmade Reservoirs in the United States,” Dam, Hydropower and Reservoir Statistics, United States Society on Dams. http://www.ussdams.org/uscold_s.html.
According to the U.S. Geological Survey, U.S. water utilities supply 44.2 billion gallons a day to homes and businesses, about 11 percent of the water the nation uses each day if you include electricity generation and irrigation. That 44.2 billion gallons comes to 136,000 acre-feet of water, so the 28.5 million acre-feet in a full Lake Mead would last 210 days.
USGS water-use statistics are here:
Estimated Use of Water in the United States in 2005, USGS, 2009 (PDF). http://pubs.usgs.gov/circ/1344/pdf/c1344.pdf.
4. Las Vegas’s formal allocation from Lake Mead is about 300,000 acre-feet of water a year. Las Vegas takes about 450,000 acre-feet, because it returns 180,000 acre-feet of treated water back to the lake, for a total “use” of 270,000 acre-feet in recent years. But even at 450,000 acre-feet, the 28.5 million acre-feet in Lake Mead would last Las Vegas 63 years.
When it’s full, Lake Mead is 157,900 acres, so if Las Vegas takes 270,000 acre-feet a year, that would lower a full lake 1.7 feet. The surface area of the lake shrinks as it falls, so Las Vegas’s 270,000 acre-feet in net withdrawals typically lower the lake between 2 and 3 feet a year.
5. Details of Las Vegas’s and Nevada’s water entitlements can be found in the most current strategic plan of the Las Vegas area’s water authority, the Southern Nevada Water Authority (SNWA): Water Resource Plan 09, Southern Nevada Water Authority, 2009, p. 15 (PDF). http://www.snwa.com/html/wr_resource_plan.html.
The “Law of the River,” a series of laws, court cases, and agreements among the states and the federal government, fixes how much water the various users of the Colorado River are allowed to take.
The law around use of the water is baroquely complex. The basic allocations for the three states tapping the lower Colorado, using Lake Mead, are: California, 4.4 million acre-feet a year; Arizona, 2.85 million acre-feet a year; Nevada, 0.3 million acre-feet a year.
6. The population of metro Las Vegas (Las Vegas and Clark County) in 1980 was 462,000. Thirty years later, it was 2 million. This chart, from the Las Vegas Convention and Visitors Authority, provides population figures going back to 1970:
Population Trends, Las Vegas Convention and Visitors Authority (PDF). http://www.lvcva.com/getfile/241/Population%202009.pdf.
The SNWA says that per-capita, per-day water use in Las Vegas in 2009 was 240 gallons, the lowest it has been in the last 14 years. What 240 gallons per person per day means is that each new resident requires 87,600 gallons of water a year.
The number of hotel rooms in metropolitan Las Vegas was 45,815 in 1980. In 2009, it was 148,941.
Historical Las Vegas Visitor Statistics (1970–2009), Las Vegas Convention and Visitors Authority (PDF). http://www.lcva.com/getfile/80/Historical%201970%20to%202009.pdf.
7. Lake Mead has only been as low as it was in August 2010 twice before—for a few months in 1964–65, and for a few months in 1956. Lake Mead’s historical water levels, going all the way back to February 1935, are here, month by month:
Lake Mead at Hoover Dam, Elevation (Feet), U.S. Bureau of Reclamation, Lower Colorado Region. http://www.usbr.gov/lc/region/g4000/hourly/mead-elv.html.
In terms of how much water has been lost in Lake Mead, according to the Bureau of Reclamation figures for July 2010, Lake Mead is holding 10.5 million acre-feet of water, or 41 percent of capacity (level, 1,088.8 feet). Using that figure, Lake Mead’s usable capacity is 25.5 million acre-feet, meaning 15 million acre-feet have disappeared since January 2000.
The Strip is conventionally defined as being 4.2 miles long (from Sahara Avenue on the north to Russell Road on the south). If, generously, you define the Strip’s boundaries to extend a mile on each side of Las Vegas Boulevard, then the area of the Strip is an oblong shape of roughly 8.4 square miles, which is 5,376 acres.
Fifteen million acre-feet of water would cover 5,376 acres of land to a depth of 2,790 feet, slightly more than half a mile.
8. Figures for the number of visitors, and the percentage of visitors from the U.S.:
2009 Las Vegas Visitor Profile Study, Las Vegas Visitors and Convention Authority, GLS Research, p. 82 (PDF). http://www.lvcva.com/getfile/107/2009%20Las%20Vegas%20Visitor%20Profile.pdf.
9. The average historic level of Lake Mead is 1,173 feet, and Intake 1 stops being usable when the lake falls to 1,050 feet. Here is a good graphical representation of the history of Lake Mead water levels:
Lake Mead Water Levels—Historical and Current. http://www.arachnoid.com/NaturalResources/.
10. Pat Mulroy has told the story of trying to get rid of the smaller fountains on several occasions, including directly to me. Most of this account comes from interviewing Mulroy, and I’ve used contemporary newspaper accounts to check her version. But this quote, comparing the fireboat at New York New York and the canals at the Venetian, is from an oral history with Mulroy in the book:
Corinne Platt and Meredith Ogilby, Voices of the American West (Golden, CO: Fulcrum Publishing, 2009), p. 268.
11. It’s important to understand that the figures for gallons of water used per person per day (GPCD—gallons per capita per day) do not reflect how much water each person in Las Vegas (or any U.S. city) uses. They are simply total water consumption in the metro area, divided by total population. They include water used at hotels and hospitals, at factories and restaurants. But GPCD is a good measure of changing use overall in a community. The figures for gallons of water used per person come from the Southern Nevada Water Authority.
12. Robert Reinhold, “Battle Lines Drawn in Sand as Las Vegas Covets Water,” New York Times, April 23, 1991. http://www.nytimes.com/1991/04/23/us/battle-lines-drawn-in-sand-as-las-vegas-covets-water.html.
13. The “volume discount” line comes from a profile of Mulroy written when she had been on the job just five months:
Jamie McKee, “Conserve Now or Pay More, Water Manager Warns,” Las Vegas Business Press, April 19, 1990.
14. Both the county commissioner’s quote, and Mulroy’s, are from:
Reinhold, “Battle Lines Drawn in Sand as Las Vegas Covets Water.” http://www.nytimes.com/1991/04/23/us/battle-lines-drawn-in-sand-as-las-vegas-covets-water.html.
15. Barbosa says that during the slowest part of the 2008–2009 recession, work at Mission’s Plant 50 was cut back from 22 hours to 16 hours a day, and water-use volumes fell by almost half. By summer 2010, business in Las Vegas’s hotels and at Mission’s laundry plants was picking back up.
16. Angel Park course superintendent Bill Rohret provided the figures on Angel Park’s water use and rounds of play. The calculations of water use per round of golf work like this. Angel Park has two large, 18-hole courses, and a smaller, 12-hole, par-3 course.
