The Colorado River is overused and shrinking. Inside the crisis transforming the Southwest

The Colorado River begins as melting snow, trickling from forested peaks and coursing in streams that gather in the Rocky Mountains’ meadows and valleys.
Its major tributaries form like arteries across Colorado, Wyoming, Utah, and New Mexico, eventually joining to form a great river unlike any other — a river that travels more than 1,400 miles and has defined the rise of the American Southwest over the last century.

Water diverted from the river has allowed agriculture to spread across 5 million acres of farmland while also feeding the growth of cities from Denver to Los Angeles, supplying approximately 40 million people.The bounty of the river has provided the foundation for life and the economy in seven states and northern Mexico.

However, the region has long relied too heavily on the river, taking more than its flows can support.In addition, the river’s water-generating heart in the Rocky Mountains has begun to fail in recent years.The Colorado River can no longer withstand the arid West’s insatiable thirst.

The Colorado River Compact, signed a century ago, divided the water among the states.The agreement established a system that overestimated the river’s capabilities.After years of warnings from scientists and insufficient adaptation efforts, that system is now colliding with the reality of an overused and shrinking river.

The Colorado River’s flow has decreased by about 20% in the last 23 years, as rising temperatures caused by the burning of fossil fuels exacerbated the worst drought in centuries.Reservoirs have reached record lows, and the shortage is worsening.Scarcity is forcing the region to confront a water crisis.

The looming consequences include significant reductions in supplies used for crop production and city maintenance.The distribution of those water reductions among states, water districts, and tribes has yet to be determined, and it could be negotiated, dictated by the federal government, or fought in court.However, the need to reduce overall water use will almost certainly result in less water flowing to farms, more water restrictions for residents, and fewer green lawns, as well as calls to limit growth, shift away from thirsty crops like alfalfa, and dedicate less water to golf courses and other water-guzzling businesses.

The Colorado River Basin, which stretches from Wyoming to northern Mexico, is grappling with unanswered questions about how to adapt, at what cost, and where the cuts will be most severe.The task of reducing water use is made more difficult by an allocation system that promised now-nonexistent water on paper, as well as a legal system that favours those with the oldest, most senior water rights.

Water agency managers have reached agreements to take less water from the river in recent years.However, these reductions have not been sufficient to halt the river’s downward spiral.As Lake Mead, the nation’s largest reservoir, continues to fall toward “dead pool” levels, the need to limit water demand becomes more pressing.

Adaptation efforts will necessitate difficult decisions about how to deal with the reductions while minimising the impact on communities, the economy, and the river’s already degraded ecosystems.Adapting may also result in a fundamental rethinking of how the river is managed and used, redrawing an out-of-balance system.

This reckoning with the reality of the river’s limits is about to transform the Southwest’s landscape.Brian Domonkos skied up through a forest of snow-covered pines to the Colorado River’s headwaters in the Rocky Mountains.He’d come to check the snowpack at an isolated stand of monitoring equipment near Berthoud Pass, Colo., where 5 inches of snow had fallen the day before.

“I hope this holds on a little while longer,” said Domonkos, a snow survey supervisor for the federal Natural Resources Conservation Service. He was concerned that even with the snowfall, Colorado seemed headed for a below-average snow year.Last spring, the snowpack across the Upper Colorado River Basin stood at 86% of average. By the end of July, however, the melting snow brought runoff that measured just 67% of average.This pattern has emerged year after year in the river’s headwaters. A near-average snowpack has often translated into meager flows in the Colorado River and its tributaries.

Storms have brought an above-average snowpack to the watershed this winter.However, snow can only go so far in replenishing reservoirs that have been declining for more than two decades.Temperatures in the upper watershed, where the majority of the river’s flow originates, have risen by about 3 degrees since 1970.This has contributed to the longest dry spell in at least 1,200 years.

As temperatures rise, trees and other plants absorb more water, and more moisture evaporates from the landscape.Long dry spells in the mountains have left the soils parched in recent years.When the snow melts in the spring, the amount of runoff flowing in streams is often reduced.”There is less water,” Domonkos said.
“And we will have to adjust.”The mainstem of the river begins in Rocky Mountain National Park, winding through an alpine valley before flowing into reservoirs and meandering through ranchlands.

Wendy Thompson lives on one of these ranches, and she can see the river from her window.She walked to the river’s edge, where muddy brown water rushed by.

Thompson, 67, recalls much more snow in Colorado when she was a child.The swollen river used to flood the pastures.”The last time we really had a flood here was in 1985,” she said.The river has shrunk due to upstream diversions and dry years.Some sections of her ranch now only flow a few feet deep.Thompson used river water to irrigate her hay fields in late spring and early summer, and she sold the crop to other ranchers.

Many ranchers have recently had less water available for their pastures, and some have sold cattle to reduce their herds.”Everyone knows we’re dry,” Thompson explained.”When there is no water in this area, you just don’t irrigate.”

Water is diverted and routed to the east from western Colorado’s ranchlands, passing through a series of tunnels beneath the Continental Divide to supply Denver and other growing Front Range cities.The Chimney Hollow Reservoir and the Gross Reservoir expansion are both under construction to hold more water.Ken Fucik, a retired environmental scientist and board member of the Upper Colorado River Watershed Group, is concerned about the Grand Lake diversions.He expressed concern about the lake’s water quality and recent algae blooms in nearby reservoirs.

Fucik questioned whether the new reservoir projects are necessary given that the river’s existing reservoirs are rapidly depleting.”Where will that water come from?” he wondered.For more than a century, monumental human efforts to control and exploit the Colorado River’s waters have shaped its history.For millions of years, the river has carved its way through layers of sandstone, limestone, granite, shale, and schist to form the Grand Canyon.Indigenous peoples have lived along the river and its tributaries for thousands of years, leaving petroglyphs and pictographs on canyon walls.

The muddy, silt-laden waters that coursed through canyons were described by the river’s Spanish name, colorado, or red.As white settlers moved west in the mid-1800s, steamboats chugged up the lower Colorado River, paddlewheels turning.Settlers began diverting water from streams and rivers under the prior appropriation system — “first in time, first in right.”

Water was regarded as a source of wealth to be exploited.The great ambition of politicians, engineers, and fortune-seekers was to tame and harness the river’s water.They focused on building irrigation projects to “reclaim” the arid lands in the early 1900s, a phrase central to the purpose of the Reclamation Service, which was established in 1902 under President Theodore Roosevelt and later became the Bureau of Reclamation.

Some warned against relying too heavily on the river from the start.”I tell you, gentlemen, you are piling up a heritage of conflict and litigation over water rights, for there is not enough water to supply these lands,” John Wesley Powell, leader of the historic 1869 expedition down the river through the Grand Canyon, famously told attendees at an 1893 irrigation congress in Los Angeles.

Before the signing of the Colorado River Compact in 1922, some scientists warned of a lack of water, but their warnings went unheeded.The compact allocated 7.5 million acre-feet of water to the Upper Basin states of Colorado, Wyoming, Utah, and New Mexico, and 7.5 million acre-feet to the Lower Basin states of California, Arizona, and Nevada.A 1944 treaty granted Mexico 1.5 million acre-feet.

During a particularly wet period in the early twentieth century, the river was divided among the states.During the 1930s Great Depression, the Hoover Dam was built.Glen Canyon Dam’s concrete pouring was completed in 1963.The dams and reservoirs, according to Los Angeles Times columnist Michael Hiltzik, “created only the illusion of abundant water, not the reality.”

Over the last half-century, so much water has been diverted that the river has been completely depleted for many years, leaving dusty stretches of desert where it once flowed to the sea in Mexico.Even in the 1980s, when there was plenty of water in the reservoirs, some foresaw that the Colorado would be unable to meet all of the demands placed on it.

Marc Reisner predicted chronic shortages in the coming years in his seminal 1986 book “Cadillac Desert,” saying the region had already begun to “found on the Era of Limits.”With humanity’s warming of the planet, the river’s strains have grown more acute.Scientists repeatedly warned in the 1990s and 2000s that chronic river overuse, combined with the effects of climate change, would likely drain reservoirs to dangerously low levels.

During the last decade, scientists discovered that higher temperatures have caused roughly half of the decline in river flow; that climate change is driving the aridification of the Southwest; and that for each additional 1 degree Celsius (1.8 degrees Fahrenheit), the river’s average flow is likely to decrease by about 9%.

The drying of Colorado’s upper reaches has reduced flow and has accelerated Lake Powell and Lake Mead’s declines.According to Becky Bolinger, assistant state climatologist at the Colorado Climate Center, the water-diverting system, including the agreement signed a century ago, was designed for a climate that no longer exists.She compared continuing this pattern of overuse to depleting a bank account by overspending and edging closer to bankruptcy.

“It’s not going to work for anyone,” said Bolinger.”What we really need to do is rework the budget completely.”The federal government has begun to lay the groundwork for reducing water consumption.Annual diversions must be reduced by 2 million to 4 million acre-feet, or 15% to 30%, according to Interior Department officials.They have urged the seven states that rely on the river to reach an agreement, while warning that cuts may be necessary.

So far, state and water agency negotiators have been unable to reach an agreement on how to share such significant reductions.Some people are concerned that these disagreements will result in lawsuits.Time is running out as the reservoir levels continue to fall.”We have to put a stop to these extra water uses right now, the uses of water beyond what is supplied.”Either we stop them or nature will,” said Brad Udall, a Colorado State University water and climate scientist.
“Make no mistake about it.This is a full-fledged five-alarm fire right now.”

The Colorado River has reached this critical stage during a decade in which extreme droughts have reduced other rivers to historic lows around the world, from the Mississippi and Rio Grande to China’s Yangtze and Europe’s Danube and Rhine.

Climate change, according to research, is intensifying the water cycle, resulting in more intense and frequent droughts, as well as more intense rainfall and floods.
Researchers discovered that streams in the western and southern United States have been drying out over the last 70 years, with flow data revealing longer and more severe low-flow periods.

Even as wet and dry cycles come and go, the Colorado River is on a long-term downward trend of aridification due to higher temperatures, according to Udall.

“It’s fundamentally changing, and it’s not going back to how it was,” Udall explained.”We’re going to have to talk about long-term water-use reductions.”This story first appeared in the Los Angeles Times.