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One-Quarter of the World’s Population Faces High Water Stress; Arizona and Nevada Face Mandatory Water Cutbacks


“17 Countries, Home to One-Quarter of the World’s Population, Face Extremely High Water Stress.”

Figure 1: Overall Water Risk. Source: World Resources Institute.

So says the title of a report issued recently by the World Resources Institute (WRI). Behind the florid headline lies a somewhat more complex, but still very dangerous, reality.

Figure 1 maps the overall water stress. This is a statistic that combines 13 different kinds of water risks into one summary statistic. Thus, the color coding on the map does not translate directly to a physical measure of any specific threat, but rather represents the level of threat from all combined. The report discusses the risks individually, and they can be mapped using the Aqueduct tool available at the WRI. They are:


Quantity Risks                           Quality Risks                           Regulatory Risks

Baseline water stress               Untreated wastewater           Unimproved/no drinking water
Baseline water depletion          Coastal eutrophication          Unimproved/no sanitation
Groundwater table decline                                                      Peak RepRisk country EST risk
Interannual variability
Seasonal variability
Drought risk
Riverine flood risk
Coastal flood risk


You can see that large swaths of Africa, the Middle-East, India, and China face extremely high risk. Those who read the environmental sections of the news may recall that Chennai, India (a city of over 7 million, formerly called Madras) is currently facing a severe water crisis. This city of over 7 million people reached “Day Zero” in June, when the reservoirs ran dry, and the city water company could no longer provide water. The rich pay exorbitant rates for water that is privately trucked in from hundreds of miles away, but average people get a small allocation (less than 8 gallons per day) that is brought in by the government, and they have to walk long distances to distribution points. The temperature just now in Chennai is ranging from a low of 80 to a high of 92, and the humidity is near 90%. Can you imagine living in that heat with only 8 gallons of water every day?

Those with slightly longer memories may remember that Cape Town, South Africa, faced a similar situation last year. Reservoirs hovered at 15-30% of capacity. Had levels reached 13.5% of capacity, the water company would have turned off deliveries, and people would have had to queue for water, just as in Chennai. Heavy monsoons in the summer of 2018 partially refilled the reservoirs, and “Day Zero” has been forestalled for the time being.

In both cases, the water crises were slow motion train wrecks, building slowly over years. Mismanagement and failure to perform upkeep on the water infrastructure played a role, but the primary culprit was increased population. Cape Town’s population grew from 2.4 million in 1995 to 4.1 million in 2015, an increase of 71%. Chennai’s population grew from under 1 million in 1941 to 4.3 million in 2001, and then exploded to 7 million in 2011. These population increases represented huge increases in demand, and supplies did not keep up. In both cases, however, the crises themselves were triggered by severe drought. A drought can cause the supply of water to plummet. If a region consumes almost all of its water supply, when a drought starts, the region can very suddenly find itself in a serious shortage. If the drought persists, the region will drain its reserves, and then the taps will go dry.

Given that population continues to increase, and climate change is predicted to cause longer, more severe droughts, it is a situation we are likely to see more often in the future.

Figure 2: Baseline Water Stress. Source: World Resources Institute.

Most regions of the United States are somewhat less vulnerable to pollution and eutrophication, and have access to sanitation and treated potable water. Thus, for Figure 2, I have chosen a map of Baseline Water Stress for the Continental United States, which measures total water consumption compared to total renewable water availability. On this map, Extremely High means the region consumes more than 80% of its renewable water supply, High means it consumes 40-80%, Medium High means it consumes 20-40%, Low Medium means it consumes 10-20%, and Low means it consumes less than 10%.

The areas of higher risk tend to be in the western half of the country, which should come as no surprise. The largest area of extreme risk includes California’s Central Valley, Los Angeles, San Diego, and the Imperial Valley. That should come as no surprise to readers of this blog, I’ve reported on it many times. But extreme risk is not confined to California. There are areas of extreme risk in Arizona, Utah, Eastern Washington/Oregon, New Mexico Colorado, Texas, and Minnesota. There is even one from St. Louis to Memphis, running along the Mississippi River. In all of these locations, a partial loss of water supply would quickly throw the area into deficit.

None of these areas has faced “Day Zero” in the way Cape Town and Chennai have. But they are getting close. Drought in California a few years ago led to the imposition of mandatory water restrictions, and the 2011 drought in Texas drained the E.V. Spence reservoir to 1% of its capacity, causing billions of dollars in damages, threatening the future of Robert Lee, a nearby town that depends on the reservoir.

Just 3 days ago (8/15/19) the Bureau of Reclamation announced that Arizona and Nevada will experience cutbacks in their allocation of water from the Colorado River, starting January 1. As I reported just a few weeks ago, Lake Mead is actually higher than it has been for 5 years. However, the states and countries that draw on Colorado River water have finally taken the situation seriously, and a new agreement to save Lake Mead from going dry was signed earlier this year. While the old system didn’t force cutbacks until the lake was at 1,070 feet above sea level, the new agreement starts phasing them in if the surface of the lake falls below 1,090 feet. (They measure the lake by how far above sea level its surface is. The lake is nowhere near that deep.) It is projected to be at 1,089.4 next January. Arizona will see a cutback of 6.9% of their water allocation.

It is tempting to think of the extreme crises in Chennai and Cape Town as Third World events; such things could never happen here, we might think. But the trends that caused the problems in both Chennai and Cape Town are at work in Arizona, California, Texas, and all across the West: increasing population, leading to increased demand, plus longer and harsher droughts, caused by climate change. Will they lead to similar crises? Will people be surprised and wonder how things could have gotten to such a point? I guess time will tell.


Hofste, Rutger Willem, Paul Reig, and Leah Schleifer. “17 Countries, Home to One-Quarter of the World’s Population, Face Extremely High Water Stress.” World Resources Institute. Downloaded 8/11/2019 from https://www.wri.org/blog/2019/08/17-countries-home-one-quarter-world-population-face-extremely-high-water-stress.

James, Ian. 2019. “First-Ever Mandatory Water Cutbacks Will Kick In Next Year Along the Colorado River.” azcentral.
Viewed online 8/18/2019 at https://www.azcentral.com/story/news/local/arizona-environment/2019/08/15/colorado-river-water-drought-arizona-nevada-mexico-first-ever-reductions/2021147001.

U.S. Bureau of Reclamation. Reclamation Announces 2020 Colorado River Operating Conditions. Downloded 8/18/2019 from https://www.usbr.gov/newsroom/newsrelease/detail.cfm?RecordID=67383.

Wikipedia contributors, “Cape Town water crisis,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Cape_Town_water_crisis&oldid=911322360 (accessed August 18, 2019).

Wikipedia contributors, “2019 Chennai water crisis,” Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=2019_Chennai_water_crisis&oldid=910798196 (accessed August 18, 2019).

World Resources Institute. Aqueduct Water Risk Atlas. Maps downloaded 2019-08-18 from https://www.wri.org/aqueduct.

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