Jeopardy Question: This Body of Water Determines the Fate of the Modern Day Anasazi

The answer is Lake Mead and the civilization that is about to disappear like the Anasazi is Las Vegas and its profligate life style.  We were motivated to write this essay, partly because it is a piece in the puzzle of a larger theme that we have begun on complex adaptive systems (CAS: The Operative Principle Behind Everything) and partly by this article from Zero Hedge: Las Vegas Is “Screwed”; The Water Situation “Is As Bad As You Can Imagine”. We first look at a few facts about Las Vegas. Then we look at Lake Mead and its importance to the region. Finally we look at the present state of affairs and Las Vegas’ future.

Las Vegas

Looking at Las Vegas first, we are told by Wikipedia that (emphasis added):

Las Vegas is situated within Clark County in a basin on the floor of the Mojave Desert and is surrounded by mountain ranges on all sides. Much of the landscape is rocky and arid with desert vegetation and wildlife. The peaks surrounding Las Vegas reach elevations of over 10,000 feet, and act as barriers to the strong flow of moisture from the surrounding area. The elevation is around 2,030 ft (620 m) above sea level. Las Vegas’ climate is a subtropical, hot desert climate (Köppen climate classification: BWh),

So it’s a city in a desert. Las Vegas has an average annual rainfall of 4.19 inches versus Nevada’s average of 8.28 inches. Of this, 43% falls in the winter months. To the end of May 2014, Las Vegas’ rainfall was 83% below average as shown in Figure 1.

Figure 1. Average annual rainfall and current rainfall.

Las Vegas rain
Source: Image captured from the interactive graph at this site.

As of July 1, 2014, the Las Vegas Sun reports the current stretch of rain-free days at 121 with a precipitation total of 0.31 inches this year, slightly below the number in Figure 1.

Water Sources and Usage

Historically, there was an oasis where Las Vegas was originally settled, located in a wash formed by the drainage basin it sits in. In 1990, the wash was dammed to contain rainwater, forming the 320-acre (130 ha) artificial lake, Lake Las Vegas. By this time, the oasis and a natural wetland had been destroyed. The city, however, derives 90% of its water from Lake Mead which we will discuss in the next section. The other 10% is pumped from groundwater sources (see: Las Vegas Valley Water District Water Resources).

Conservation assisted by economic factors has reduced water consumption in Southern Nevada  29 percent from 314 gallons per capita per day (GPCD) in 2002 to 222 GPCD in 2011 with a conservation goal of 199 GPCD by 2035 (Water Resources). Surprisingly a search of comparative water consumption by city and/or by state yielded no data although it should exist somewhere.

An important development in Las Vegas’ water resource acquisition is the use of water mining in valleys north of Las Vegas. The Las Vegas Sun ran a 5-part series titled Quenching Las Vegas’ Thirst. Part four, ‘Owens Valley is the model of what to expect’, describes the convoluted machinations used by bureaucrats, lawyers and state and local officials along with the perversion of science to create a project to pump and transport by pipeline, 40,000 acre-feet of water a year for 10 years to Las Vegas. After this period, increases may be granted for another 50,000 acre-feet of water a year, essentially until the aquifers run dry in an Owen’s Valley scenario.

Lake Mead

Lake Mead was created by the construction of the Hoover Dam on the Colorado River in 1935. A view looking up lake from the dam in 2013 in Figure 2 shows a remarkable white “bathtub ring” that marks the part of the shoreline cliffs that historically were largely underwater.

Figure 2. Lake Mead at the Hoover Dam, July 2013.

Source: Groksurf’s San Diego.

If we look at the graph of the lake level from its creation in 1935 shown in Figure 3, we see that current levels are near record lows.

Figure 3. History of Lake Mead Water Levels (feet above sea level).


As of June 30, the Bureau of Reclamation reported that the level of Lake mead stood at 1082.66 feet. The next day it stood at 1082.52 feet. The latter is only 0.58 feet above the record low of 1081.94 feet set in Nov. 2010 (see complete data set). With a drop of 0.14 feet in one day, Lake Mead will reach a record low (since filling) on Independence day July 4 or the next day July 5. However, checking on July 4 we see that the level on the 3rd was 82.04 feet. Ironic.

(As a parenthetical aside, we checked on the 5th and the level actually rose 0.03 feet on the 4th. This was at a cost of a 42.7% reduction in generation from the day before and a 42.2% reduction in the number of acre-feet of water released. One might be tempted to think authorities do not want to set a new record low. If this is the case we will see how long they can hold out and what the cost will be.)

In Figures 4 and 5 we are able to visualize levels of importance for the lake.

Figure 4. A cross-section of Lake Mead showing some critical levels or elevations (feet above sea level).

Source: Carleton University Earth Analysis Techniques.

Figure 5. Intake levels for the Las Vegas aqueducts.

Source: Global Warming Forecasts.

The key levels are:

  • 1082 feet. The current level of lake mead as this essay is published.
  • 1050 feet. At this point the first intake for the Las Vegas aqueduct system ceases to  operate. Also, power generation ceases (Colorado River Water).
  • 1000 feet. The second newer intake for the aqueduct system ceases to work.
  • 850 feet. The city is currently building a third intake at this level. The $817 million rescue mission is expected to be finished by the end of 2015 (Malaysia Chronicle: Is Las Vegas about to go out of business?).
  • 720 feet. At this point, Lake Mead and the Colorado River are dry. Before this point is reached however, the river will become a series of “dead pools” (also the book Dead Pool). Presumably Las Vegas water will be shut off before this is allowed to happen.

The Hoover Dam Wikipedia article has a considerable discussion on power generation. Not surprisingly, the amount of power generated is a direct function of the level of the lake.The Bureau of Reclamation tells us that:

The average annual net generation for Hoover Powerplant for 1947 through 2008 was about 4.2 billion kilowatt-hours. The ten-year annual average for 1999 through 2008 was about 4.2 billion kilowatt-hours. The maximum annual net generation at Hoover Powerplant was 10,348,020,500 kilowatt-hours in 1984, while the minimum annual net generation since 1940 [when the reservoir was filled to capacity] was 2,648,224,700 kilowatt-hours in 1956.

The allocation of power from the dam is shown in Table 1.

Table 1. Power allocation from the Hoover Powerplant (HP).

Area Percentage
Metropolitan Water District of Southern California 28.53%
State of Nevada 23.37%
State of Arizona 18.95%
Los Angeles, California 15.42%
Southern California Edison Company 5.54%
Boulder City, Nevada 1.77%
Glendale, California 1.59%
Pasadena, California 1.36%
Anaheim, California 1.15%
Riverside, California 0.86%
Vernon, California 0.62%
Burbank, California 0.59%
Azusa, California 0.11%
Colton, California 0.09%
Banning, California 0.05%

Source: Wikipedia and the Bureau of Reclamation.

To put the HP contribution into perspective, the EIA in Profile Analysis notes that:

Natural gas-fired power plants typically supply two-thirds of Nevada’s net electricity generation. Coal-fired plants supply about one-sixth, and renewable energy sources, mainly geothermal and hydroelectric power plants, supply the rest. Minimizing use of scarce water in conventional generation is a priority for Nevada. The state’s largest generating plant, NV Energy’s Chuck Lenzie station, uses high-efficiency natural gas combined cycle technology, recycles three-fourths of used water, and, to reduce water use, employs one of North America’s largest air-cooled condenser systems.

Nevada is one of the few states that generate electricity from geothermal resources, and those resources account for nearly half of the state’s renewable power generation.

This means that HP supplies less than 10% of Nevada’s electricity needs (for other generation sources see NVEnergy). As for Las Vegas, we find in the 2007 Forbes article, Lighting Las Vegas, that: The city demands 5,600 megawatts on a summer day. By 2015 that’s expected to hit 8,000 [megawatts per day].

In summary,the HP contribution is a relatively small component of Nevada’s and Las Vegas’ electricity supply, especial since Las Vegas is connected to the national grid and in a sense is independent of HP. A number of utilities and power authorities supply the region which is grid-connected providing access to the open market. One cannot infer a direct dependency between HP power and Las Vegas demand.

The Future of Lake Mead

The Las Vegas Review-Journal published an article in 2008 titled Lake Mead dry as a bone?  In it the author cites a Scripps Institute paper, When will Lake Mead run dry? by T. P. Barnett  and D. W.,Pierce  (J. Water Resources Research, v. 44, W03201, doi:10.1029/2007WR006704.). In an associated news release and summary of the paper by Scripps, the key points are (emphasis added):

There is a 50 percent chance Lake Mead, a key source of water for millions of people in the southwestern United States, will be dry by 2021 if climate changes as expected and future water usage is not curtailed …


The researchers estimated that there is a 10 percent chance that Lake Mead could be dry by 2014. They further predict that there is a 50 percent chance that reservoir levels will drop too low to allow hydroelectric power generation by 2017.

Reading the actual paper is fruitful because although they project that there are approximately 29 years left, or calendar year 2036, before the
combined Mead/Powell system is at dead pool elevation, the assumptions show the problem of assigning a degree of reliability to their figures. These include

  1. select climate models and statistical studies used to project decreases in runoff (-0.06 million acre-feet (maf) per year);
  2. starting by assuming a current steady state where inflow to the reservoirs is equal to their discharge, ignoring the fact that Lake Mead was being overdrafted by about 1 maf per year at that time;
  3. assuming the changes are temporally linear; and
  4. levels of consumption are constant.

The assumption of constant consumption in point 4 places this study as the latest date for the critical point to be reached. The competition for Colorado River water spans seven states (Colorado River Water Users Association, also image) and two countries. Competing uses include crop irrigation, livestock, thermoelectric power generation, public supply and mining and industry (Consumptive Water Use in Southern Nevada). The battles for a dwindling resource to supply expanding demand will be complex and fractious – and unlikely to save the river.

On point 3, linearity is a bad assumption as we will point out in the next section. And the steady state assumption in point 2 would seem equally flawed.

Finally, climate models have been notoriously unsuccessful in predicting global warming (Global Warming Update). In Another Dry Essay we looked at the drought in the southern US. In particular, we reviewed the idea of megadroughts which are independent of the notion of anthropogenic global warming. Drought is common to the area for periods of varying duration and this may simply be one of the longer ones. We will know when it is over.

Update 20150626: Leaking Las Vegas: Lake Mead At Record Lows, “We Have To Change”.


The Future of Las Vegas

A flurry of articles has recently appeared on the scene, forecasting Las Vegas’ demise. Some have been cited above. Here are a couple more examples: Study suggests Las Vegas’ water supply has 22 years and The race to stop Las Vegas from running dry. However, they all refer back to the 2008 study and add nothing new. Finally, for what may appear sensational reporting but may be closer to the truth than the other articles is this one from Natural News: Los Angeles, Las Vegas, Phoenix and other cities headed for imminent water supply collapse; wave of drought refugees now inevitable.

The final piece of information we need is the population growth of the greater Las Vegas area shown in Figure 6.

Figure 6.Las Vegas population growth from incorporation to 2012

Source: Sellstate Deluxe Realty.

Las Vegas exhibited exponential growth until about 2000 when it appears more linear to 2010 at which point it appears to level off. A video by Chris Martenson (“Massive Change Is Upon Us” – The Three ‘E’s) that started us on this current writing binge and on which we hope to write soon, dealt with the exponential growth of most facets of human civilization. The initial idea that a finite resource can have peak supply characteristics, first developed as Hubbert’s peak oil theory, has more recently been extended to groundwater and many of our mineral resources.

The fact is that for almost all resources, we have collected, mined and harvested the cheap, readily available material. What remain are much more costly to extract. For Las Vegas, this includes water.

Table 1 shows the agents affected by the HP generation. The total generation on the Colorado River is larger but will likely function as a single unit in terms of a collapse of water in the watershed. A loss of this generation can be replaced because the collapse if it occurs will be over time rather than instantaneous. Replacing this power simply throws more of a burden on other diminishing resources, just as Las Vegas’ desperate attempt to mine water elsewhere simply shifts the inevitable decline both temporally and spatially.

We are linear deterministic thinkers. Another description of our thought processes is that we think in “silos”. Broad dynamic networks of independently acting agents are beyond our ability to model and rationalize so we simply ignore them. Las Vegas’ fate may be as much affected by a bunch of snails as by our ability to build long aqueducts. What is certain is that the fate of Las Vegas is tied to the fate of the entire Colorado River basin. All entities dependent on what happens to it are likewise affected, each in its own way. These are the issues that we are really interested in and starting to drive towards.

Addendum: 20140710

While we had left the issue others were still paying attention. Read Zero Hedge: Las Vegas Is More “Screwed”; Drought Drains Lake Mead To Lowest Since Hoover Dam Built. It was actually July 7 when the old 2010 record low was broken and the lake continues to drop.

Addendum: 20150415

We add a link also to an article showing Lake mead is at the lowest point on record for this time of year: Leaking Las Vegas: Lake Mead Water Levels Continue To Crash.

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