The rise and fall of civilizations
The corners of Colorado, New Mexico, Arizona, and Utah come together in the dry reaches of the American Southwest. This area, known as the Four Corners region, is rich with harsh but beautiful desert landscapes and encompasses many scenic national monuments and national parks. Long before today, the area was home to the Anasazi people for more than a thousand years. Their civilization was as sophisticated as that of the Mayans. But somewhere between 1275 and 1300 A.D, the Anasazi disappeared, and the land was left empty. A single generation was all it took to end a millennium of civilization. Should that concern us?
A glimpse of what was happening during that period can be gleaned from humble tree rings. Dry years show up as patterns of thinner, compacted tree rings, so historic droughts appear in the natural records of tree growth. If counted backward through time, the rings account for the last 1200 years, taking us back to the 800s when the first recorded megadrought ravaged the western USA. This long period of severe drought was a harbinger of repeated dry spells in the mid-1100s, the 1200s, and the late 1500s. The dry years of the late 1200s tie into the collapse of the North American Anasazi culture. As the sparse water resources of their desert homelands disappeared under the heat of a megadrought, the last of the Anasazi had no choice but to leave because, without water, there is no life.
But the Anasazi disappeared 800 years ago, seemingly separated by time and technology from today, where massive water storage and water diversion projects have changed the face of agriculture and water usage in the American Southwest. The technology is impressive. However, all the storage and diversion technology in the world is meaningless if there is no water to store.
The fate of the Anasazi is relevant to us today because researchers believe we are 20 years into the next megadrought. The tree rings tell us that the last megadrought in western America ended before the Pilgrims landed in 1620. So, the rise of modern America and the subsequent development of the American West occurred in a period of ample water. The term “ample” is used in a relative sense because, after all, we are talking about areas that are largely desert. But still, our calculations for water needs have used a higher baseline for available water than occurs in a megadrought.
Humans are generally better at chasing immediate gain as opposed to taking measured, long-term views of development. When developers apply to build massive new neighborhoods in Phoenix, the wisdom of preparing for the next megadrought is obscured in the push for profits and increases in the municipal tax base. Much like the movie “Field of Dreams,” people convince themselves to build it, and the water will come.
Perhaps the party is coming to an end. The Colorado River flows 1,450 miles from its headwaters in the Rocky Mountains to the Gulf of California. In its natural state, this river delivered about 22,500 cubic feet per second of flow. However, today, waters from the Colorado River are lucky to make it to their final destination in the Gulf of California.
The river provides water for some 40 million people, who siphon it off bit by bit. Also, it provides irrigation for 5.5 million acres, and it provides 4,200 megawatts of hydroelectric power generation capacity. The dams for these hydroelectric power plants and other storage dams hold up to four years of average annual river flow and serve as a flow stabilization system. But the demands on this river now exceed its annual flow capacity. Six major cities (Denver, Salt Lake City, Las Vegas, Phoenix, Los Angeles, and San Diego) depend on the Colorado River.
Water flow in the Colorado River has declined by 20 percent compared to the last century. The megadrought is decreasing precipitation base levels, and climate change, particularly rising global temperatures, also takes its toll. Warmer temperatures facilitate more evapotranspiration, thus increasing overall water loss from the system. So, under current conditions, river discharge could shrink another 25 percent by the middle of this century.
The clock is ticking on Lake Mead
Just 24 miles east of the Las Vegas Strip, the flow of the Colorado River comes to a stop, blocked by the Hoover Dam. The dam was built in 1935, creating Lake Mead, the largest capacity reservoir in the United States. But the lake has remained below capacity since 1983 due to drought and water shortages. As of May 2021, the water level was at 1076 feet, or 153 feet below its operational capacity. This level is significant since, at 1075 feet, one foot lower than on May 19th, the federal government must declare an official water shortage. This declaration will trigger mandatory future cuts in how much water individual states receive, if it stays in effect.
This situation engenders images of neighborhoods packing up their belongings and moving elsewhere because, without water, there is no life. Of course, we don’t know if this scenario will come to pass, but it is clearly a possibility. Granted, most people are not overly sophisticated in their understanding of mathematics, but even the simplest of us can understand the basic proposition for the Colorado River. At the beginning of the 21st century, we started using more water each year than precipitation provided to the river’s watershed. Much like a bank account, if you consistently withdraw more money than you put in, the good times will come to an end. While I confidently write that everyone can understand this concept, I do realize my statement falls against a backdrop where large numbers of people still fail to understand that 306 electoral votes are more than 232 votes.
Studies (like the “Colorado River Basin Water Supply and Demand Study” from the U.S Department of the Interior Bureau of Reclamation) provide complex scenarios on the future use of the Colorado River. However, the bottom line is that future aspirations look unrealistic under current plans. Future water demand of between 18 and 20 million acre-feet (MAF) per year is projected, against the long-term average annual supply of 16 MAF, and the megadrought has cut that 16 MAF to as low as 12 MAF in some years. Undoubtedly, if water rationing arrives, the ultimate determination of winners and losers will be more political than scientific.
But the problem is bigger than just the Colorado River. At one time, the biggest freshwater lake west of the Mississippi River was Tulare Lake in Central California. Today it is just dusty farmland. However, the disappearance of surface water is just half the problem. Between 2002 and 2014, the Central Valley’s groundwater supply was severely depleted by agricultural pumping. Enough groundwater was removed to cause the ground to sink. It’s easy to think of this as a “crop problem” unless you are one of the local residents whose drinking water well dried up.
Drought affected 80 percent of the American West in the spring of 2021, a 40 percent increase from 2020. Farmers in California found themselves paying up to four times more for water than they had planned, causing significant shutdowns in their operations. The price increases were forced as the federal government responded to water shortages by cutting water allocations. The knock-on effect will probably be rising food prices across the country.
And then there are the water towers
The water we rely on for survival arrives in two forms: rain or snow. From there, the water budget divides the precipitation into surface water, groundwater, and snowpacks. Together these snowpacks and glaciers are sometimes referred to as water towers. They collect water at high elevations during the cold, wet months and slowly feed that water back into rivers and streams during the warmer months. This action helps to keep the rivers flowing year-round.
The megadrought of the American West and rising global temperatures have taken a toll on America’s water towers. Less snow is falling, and more is melting. Clark Glacier in Oregon has lost 94 percent of its ice and is now described as a “rotting carcass of its former self.” The glacier is just one of many in the Cascade Range. Farther south, in California, the 2021 snowpack is just four percent of normal.
To the east of the Cascades, the Missouri River flows for 2300 miles traversing the USA mid-continent. It is the longest river in America. Its headwaters lie in Montana, and it runs east and south, eventually joining the Mississippi River. Along its journey, this river provides essential water to the basin’s farmers and ranchers, who raise 46 percent of the wheat, 22 percent of the corn, and 34 percent of the cattle in the United States.
In the late 13th century, when the Anasazi were fleeing their homelands, snow and ice became sparse in Montana, and the Missouri River headwaters ran dry when spring meltwaters disappeared. Mountain snowpacks no longer accumulated during the winters, thus depriving the river of vital water supplies. This event did not repeat itself again until the first decade of the 21st century.
From 2000 to 2010, the Upper Missouri River Basin was more parched than during the great Dust Bowl in the 1930s. The driest of these ten years saw conditions unmatched for 800 years.
In July of 2012, the State of Missouri was declared a disaster area due to a crippling drought. Crops failed, and municipal drinking water supplies dropped to critical levels in some areas. Drought in the upper Missouri basin also hit farmers in 2018 when poor grass growth and hay production reduced the feed available for cattle. The past two decades have seen records set for thin snowpacks and low flow in the Missouri River headwaters.
Most of us take water for granted. It is not until the taps run dry that we can start to understand that water is life. However, we have an advantage over the Anasazi. It is within our means to institute long-term planning and regulate water supplies. But even careful planning won’t completely alleviate the problem, and large numbers of people will be negatively impacted if the megadrought continues. But planning can help avoid complete collapse. We are not immune from the fate that was visited upon an ancient civilization. But we have tools at our disposal to soften the blow and help us adapt. The only real question is whether we have the will to use those tools.
See my medium publications:
Environmental Articles on EarthSphere
Stories, Life Observations and more on Dropstone
Read my recent fictional adventure on the origins of life
Sources
About 40 million people get water from the Colorado River. Studies show it’s drying up (By Ian James; USA Today)
Climate change is drying up the Colorado River, putting millions at risk of ‘severe water shortages’ (By Drew Kann; CNN)
Colorado River Basin Water Supply and Demand Study (By U.S Department of the Interior Bureau of Reclamation)
Colorado River flow dwindles as warming-driven loss of reflective snow energizes evaporation (By P. C. D. Milly & K. A. Dunne, Science)
THE FIRST STEP IN REPAIRING THE COLORADO RIVER’S BROKEN WATER BUDGET: SUMMARY REPORT
Water crisis: ‘Where rivers ran, only dust’ (By Anne Thompson, Deepa Shivaram and Priscilla Thompson; NBCUniversal)
‘It’s like a rotting carcass of its former self’: funeral for an Oregon glacier(By Oliver Milman; The Guardian)
Drought Imperils Economy in California’s Farm Country (By Jim Carlton; The Wall Street Journal)Climate Conscious
Feature Image: Falling Water Levels at Lake Mead (Modified by ArcheanWeb); Original Credit – By Cmpxchg8b – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7761370