How Arizona’s dry winter is affecting water levels

PHOENIX — Arizona’s stubbornly dry winter is resulting in weak runoff levels at major waterways. 

Water flow at the upper Salt River was measured at a paltry 130 cubic feet per second on Monday, a total that is just 20% of the average on this date.

“We’re measuring some of the lowest flows we’ve ever seen,” said Bo Svoma, a meteorologist with SRP, the state’s second-largest water utility.

The river flows into Roosevelt Reservoir, which is at 70% capacity. Arizona is on pace for the second driest winter ever recorded.

“The story’s not finished yet in terms of how dry we will be. We have about a month and a half left,” Svoma said.

He added that SRP’s network of reservoirs and underground aquifers is nonetheless “balanced” because the last two winters were wetter than normal. In 2023, Roosevelt was at a record high 106% capacity. 

“What we’ve been doing at SRP for more than a hundred years is knowing how to manage through dry winters and capitalize off the few wet winters we have in between the dry years,” Svoma said.

SRP provides about half of the Valley’s water. Its two above-ground water sources are the Verde and Salt rivers. Those account for about one-third of the Valley’s water supply, but that changes depending on how much SRP dips into underground resources in a given year. 

The other major water resource for the greater Phoenix area is the Colorado River. It has a structural deficit. The Mogollon Rim is typically wetter than the Colorado Rockies because it is closer to the Pacific Ocean, Svoma said. State and regional water experts face big challenges regarding the Colorado River, which flows through Lake Mead.

“The odds are stacked against Lake Mead. It’s getting lower. And that’s not the situation here. Our inflow into these reservoirs (The Salt River) is in the long-term balanced,” Svoma said.

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