Lake Powell Rises More Than 20 Feet After Major Flooding Across the US Southwest, Bringing Rare Relief to Drought-Stricken Reservoirs

Heavy rainfall and flooding replenish depleted reservoirs across the American Southwest

Weeks of heavy rainfall and widespread flooding across the southwestern United States have brought unexpected relief to reservoirs struggling with years of severe drought. Rivers and streams that were previously running low or completely dry suddenly filled with floodwater, sending large volumes of water into depleted lakes and underground aquifers.

Lake Powell, the second-largest reservoir in the United States, has risen more than 20 feet (6.1 meters) since reaching its lowest level in mid-September. The increase is considerably greater than the water gained during this year's spring and summer snowmelt.

The storms, which struck in late October and early November, also caused extensive flooding, forced hundreds of residents to evacuate and left some communities temporarily isolated.

Martin Hoerling, a climate scientist and hydrologist at the University of Colorado, Boulder, described the increase in water supplies as an unexpected benefit.

"That's somewhat of an unexpected boost from Mother Nature," Hoerling said.

Lake Powell gains significant water but remains only one-quarter full

Located along the Arizona-Utah border, Lake Powell has experienced extremely low water levels during the prolonged drought affecting the Colorado River basin.

Last winter's limited snowfall provided little runoff during spring and summer, when reservoirs normally receive much of their annual water supply.

The recent storms have changed that picture.

Lake Powell has gained more than 6 meters in water level, while additional rainfall and floodwater could provide a total increase of more than 1.2 million acre-feet.

According to Hoerling, that amount would be sufficient to meet the annual water needs of approximately four million average households.

Despite the improvement, the reservoir remains just over one-quarter full. As of Friday, 15 of its 17 boat launches were still unusable because of low water levels.

Experts have also linked the recent intense rainfall to El Niño, whose influence could continue affecting precipitation across the western United States for several more months.

Colorado town lifts water restrictions after nearly 180 mm of rainfall

In Pagosa Springs, CO, the storms brought a dramatic change after months of water shortages.

Before October's heavy rainfall, more than 10,000 residents in the town and surrounding communities were under water restrictions. Restaurants were even encouraged to serve drinking water only upon request.

Then approximately 178 millimeters of rain fell across the area, causing destructive flooding but also replenishing local water supplies.

Authorities have since lifted the restrictions.

"While the storm was destructive, I think there is a silver lining," said town manager David Harris.

"You're getting a good start to the winter snowpack in the higher elevations."

Arizona reservoir receives more than three billion gallons of water

Northern Arizona has also experienced a substantial improvement in water storage.

Upper Lake Mary, which supplies up to 40 percent of the water used by Flagstaff, AZ, has received more than three billion gallons of water since early October, according to water production manager Brian Huntzinger.

The most recent storms delivered the equivalent of more than two years of water supply to the city's surface water system, providing important reserves for a community heavily dependent on underground aquifers.

"It's just a great, great thing to see," Huntzinger said.

"We might be overflowing at this rate before we see any snow fly."

Farther south, floodwaters flowing into the Verde River pushed two reservoirs close to capacity, prompting officials to release water from dams into a normally dry river section near Phoenix, AZ.

Drought continues despite rising water levels

Although the rainfall has improved water supplies, the southwestern United States remains affected by long-term drought.

The US Bureau of Reclamation is unlikely to change its reservoir water release plans until the seasonal snowpack reaches its peak, typically around April.

Agency spokesperson Mary Carlson acknowledged the recent improvement but warned that "considerable uncertainty remains."

Under the federal Colorado River management plan, California, NV and Arizona are expected to collectively reduce annual water use by 1.25 million acre-feet over the next two years.

That volume is equivalent to more than 600,000 Olympic-sized swimming pools. Larger reductions remain possible depending on future conditions, while Nevada and Arizona are challenging the plan in court.

New water storage projects could help capture future rainfall

Some Arizona cities have agreed to support preliminary work on expanding an existing dam along the Verde River to capture more stormwater and reduce dependence on the Colorado River.

The project reflects growing efforts to improve water storage in a region where reservoirs, mountain snowpack and underground aquifers remain essential water sources.

Climate scientist Martin Hoerling emphasized that recent rainfall does not eliminate the challenges created by prolonged drought.

"We need to figure out how to be resilient in a drier future. And we're not quite there yet," he said.