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SRP Reservoirs Surge to 70% Full After Historic October Runoff, But Long-Term Drought Persists
A wet October and early November pushed Salt River Project reservoirs from 53% to 70% full, capturing about 120 billion gallons of water. Hydrologists warn the windfall eases only short-term drought conditions, while a proposed Bartlett Dam expansion could help capture future runoff that currently flows downstream.
A remarkably wet October and early November have delivered a major boost to the Salt River Project's water supply, pushing its reservoir system from 53% full to 70% full in less than a week, the utility reported.
The system captured approximately 120 billion gallons of water during the runoff event, most of it stored in Roosevelt Lake, which rose 22 feet. SRP senior hydrologist Stephen Flora said flows on the Salt and Verde rivers were among the highest seen since 1993.
At their peak, the Verde River carried about 94,000 cubic feet of water per second â roughly 703,000 gallons â while flows into Roosevelt Lake on the Salt River topped out at about 145,000 cubic feet per second, or approximately 1 million gallons.
"We were able to capture all of that ⦠store that, put it to use for the Valley here into the future," Flora said.
The October rainfall ranked among the 10 wettest on record for Arizona, according to the utility. The surge in storage comes as welcome news for a region that has contended with prolonged drought conditions and mounting pressure on the Colorado River system.
However, the runoff exceeded the SRP system's capacity to capture it all. On the Verde River system, where reservoirs are much smaller, water that could not be stored was released downstream.
"Once those reservoirs start to fill, those performed as they were designed to perform and pass that water safely downstream," Flora said. Much of that released water is helping recharge the aquifer, according to the utility.
The proposed Bartlett Dam reservoir expansion project aims to address that limitation by doubling the Verde system's storage capacity. The project remains in the feasibility and environmental review stage. If Congress approves it, design and construction could take 10 to 15 years and cost up to about $3.7 billion.
"A larger Bartlett Dam, if that were in place, it likely may have captured all of that runoff," Flora said. "And we would have been able to capture that and put it to use."
Despite the dramatic gains, Flora cautioned that the wet October does not signal an end to the region's long-term water challenges. SRP relies on strong years like this one to replenish its reservoirs, he said, but the underlying drought conditions remain.
"Especially for this time of year in October, that is a substantial amount of increase of water that we may see in a very good winter," Flora said. "And we're seeing that now in early November."