Why heavy winter rains and snow won’t be enough to pull the West out of a major drought

This winter, the West has been hit by cold weather. Heavy rains have ravaged California, and the Rocky Mountains are covered in snow.

That’s good news for the Colorado River, where that freeze gives a potential springtime boost to giant reservoirs crippled by drought. However, climate scientists say that the 40 million people who use river water should take the good news with a grain of salt.

The snowpack in the Rockies is vital to the Colorado River—a water lifeline for people from Wyoming to Mexico—commonly referred to as the Colorado River Basin. Before water flows through rivers, pipelines and canals to cities and the region’s farms, it begins as snow at high altitudes. In fact, more than two-thirds of the rivers in Colorado begin as snow. It has snowed this year Totals are better than average, but climate scientists say winter is far away and conditions could bring less rain.

“Everyone is very eager to make an early call on this,” said Brad Udall, a water and climate researcher at Colorado State University. “Always, you’ll catch your pants down if you think you know what’s going to happen.”

The Colorado River is in crisis, shrinking at the hands of climate change. A 23-year “megadrought” has created the driest conditions in the region In 1,800 years. This has created a supply-demand imbalance for A A multi-billion dollar agricultural sector And big cities — like Denver, Phoenix, Salt Lake City, Las Vegas and Los Angeles — that depend on river water.

Many eyes now turn to the snow-capped mountains that keep the river flowing and help fill the nation’s two largest reservoirs, Lake Mead and Lake Powell. Those reservoirs have dropped to historic lows – Endangering hydropower For millions of people and threatening the need Expensive modifications In high dams that hold back water.

Meanwhile, mountain snow accumulation is off to a promising start. Snowpack around Snowmass in Colorado is 130% above average for this time of year. The Roaring Fork watershed, which includes aspen and snowmass, makes up only 0.5% of the landmass in the Colorado River basin but provides nearly 10% of its water.

In other nearby mountain ranges, snow accumulation is between 140% and 160% of average. If those numbers continue into spring, the severity of the Colorado River drought means several years of heavy snow are needed to make a serious dent in low water levels.

“It’s great to see a big snowpack,” Udall said. “We need five or six years at 150% snowpack to refill these reservoirs. And that’s highly unlikely.”

Long view

A string of wet years is unlikely because of rising temperatures due to climate change, Udall said. Since the 1970s, temperatures in the Colorado River basin have risen by three degrees Fahrenheit. Those higher temperatures caused a 15% drop in streamflow across the region.

The temperature a A raft of alarming environmental changes across the region. In recent years, scientists have warned about soil drying. The land has become dry and The snow melts Before the water has a chance to reach the places where people run off and collect it.

Already, Udall said, winters with 90% average snowpack have resulted in only 50% spring runoff because thirsty soils act like sponges.

Even that The concept of “average” has changed Because of the warm temperature. In spring 2021, the National Oceanic and Atmospheric Administration changed the way it averaged all of its data.

Every 10 years, NOAA moves the three-decade window it uses for averaging. But the rapidly increasing effects of climate change mean that the current window from 1991 to 2020 outstrips the previous 30-year period because it includes the warmest period in recorded U.S. history.

Because of that, the snowpack data tells a somewhat confusing story. For example, if the snowpack is at 130%, the current totals look very low if compared to the typical snowpack going back more than 30 years.

“Man, we’ve got to continue to plan for the worst here,” Udall said. That’s what we’ve seen over the last 23 years. This temperature keeps telling us.”

Difficult to plan

Planning has become more difficult as changing baselines make future water availability less predictable.

Cynthia Campbell, who has advised the city of Phoenix on water laws for more than a decade, knows this firsthand. The nation’s fifth largest city gets more than a third of its water from the Colorado River.

“The worst-case scenario from our perspective is we have to get used to the mountains looking at what rain is,” Campbell said.

She said the reservoirs should act as a buffer between the fluctuations of dry years and wet years. But with a contraction in reserves Never seen beforeCities around the arid West can only plan one year at a time.

“That’s not enough time to make the changes you need to make,” Campbell said with a nervous smile. “But that’s where we are. So, in some ways, it might be our worst nightmare.”

Campbell and Phoenix residents are not alone in their uproar.

As supplies dwindle, the seven states that use Colorado River water are at loggerheads over how to reduce demand.

Water allocation throughout the basin is governed by a 1922 legal agreement that has not been substantially rewritten to meet the changing needs of the region. something Experts suggest That agreement — the Colorado River Compact — must be replaced to meet the modern demands of a region Extensive crop fields and A growing urban population.

As the drought worsens, states have agreed to a patchwork of tweaks to increase reservoirs and prevent disasters, but they have been unable to reach agreement on larger, more permanent reductions in water use.

in Meetings about the future of the riverRepresentatives from seven states — including Colorado, Utah, Arizona and California — are quick to talk about the need for a collaborative solution to their collective problem, but Reluctance to commit To sacrifice part of one’s share.

Current management guidelines for the river expire in 2026, and states are mostly focused on creating a new deal before then. Policy analysts and water managers have indicated that large cuts must come from agriculture, which uses more than 70% of the Colorado River’s water.

Make the water supply last

Meanwhile, cities have had to get creative in spreading the limited amount of water for their growing populations. Those efforts haven’t changed this winter’s heavy mountain snow or days of rain that drenched California, causing massive flooding and widespread damage.

“One storm doesn’t change the game, whether we have a wet year or not,” said Adel Hagekhalil, general manager of the Metropolitan Water District of Southern California. “We must continue to focus on building the infrastructure needed to create a local water supply.”

The district supplies drinking water to 19 million people from north of Los Angeles to the Mexican border. The agency has undertaken several ambitious projects to reuse water already in the system.

A proposed facility would be in Carson, California Drain cleaning to make it drinkable. The treatment setup is estimated to cost $3.4 billion to build. Once completed, it will cost $129 million to operate each year. That new facility aims to redirect up to 150 million gallons into municipal water supplies in and around Los Angeles.

Nevada and Arizona water agencies plan to help pay for the project in exchange for some of Southern California’s water. The hefty price tag is just one example among many New infrastructure costs Cities may be affected by climate change.

“We have to be ready,” Hagekhalil said, “and it will be on us today if we take the right steps to invest and build the necessary infrastructure.”

Elsewhere around the Colorado River Basin, governments have toyed with the idea of ​​investing in other ways to augment existing water supplies. Last year, then-Governor Doug Ducey of Arizona proposed a deal with Mexico in which the state would have a Ocean Desalination Plant In the Gulf of California. This would allow Mexico to use newly desalinated water from the Colorado River in exchange for part of Mexico’s.

Innovative solutions such as wastewater recycling and desalination have generated buzz among residents of the region’s arid cities. But water policy analysts say none of that can serve as a silver bullet for those who depend on the Colorado River. Instead, they say, significant reductions in demand are the only way to meet the challenges posed by climate change’s effects on water supplies.

This story is part of ongoing coverage of the Colorado River, produced by KUNC in Colorado and supported by the Walton Family Foundation. KUNC is solely responsible for its editorial coverage.