Local
SRP Captures 120 Billion Gallons from Historic Salt and Verde River Runoff, Lifting Reservoir System to 70%
A powerful storm sent flows on the Salt and Verde rivers surging to levels not seen in decades, allowing Salt River Project to bank roughly 120 billion gallons and lift its reservoir system from 53% to 70% capacity in just five days. The muddy aftermath has forced Tempe Town Lake to close and turned a collegiate triathlon championship into a duathlon.
TEMPE, Ariz. â A storm system that swept through the Valley this week sent the Salt and Verde rivers surging to some of their highest flows in decades, allowing the Salt River Project to capture roughly 120 billion gallons of water and lift its reservoir system from 53% to 70% capacity in just five days, the utility said.
The volume is enough to fill about 182,000 Olympic-sized swimming pools. SRP released water downstream to manage the influx as inflows ranked among the highest the utility has recorded in decades.
Stephen Flora, a senior hydrologist for SRP, said the speed and scale of the runoff were extraordinary.
"In this event, we saw as much water flow into and through our reservoirs as we get on a normal winter, all winter," Flora said. "Just in a few days, we saw what we get all winter: January through May."
Flora described the inflows in such a short period as "huge."
The surge offers a measure of relief for a state that has endured years of drought, though Arizona's water outlook still hinges on snowpack in the mountains that feed the system. Flora said wet years like this one are essential for replenishing supplies that carry the region through drier stretches.
"We really rely on these types of years that help refill the system to get through those dry years like we've seen the last few years," he said.
As SRP scales back releases toward normal levels, the consequences of the runoff are still being felt downstream. At Tempe Town Lake, the water turned murky and is only slowly clearing â too slowly for the Women's Collegiate Triathlon National Championship hosted by Arizona State University.
ASU said testing found the water was not safe for the swim portion of the race, so the event was converted to a duathlon. Tempe officials said the lake will remain closed to water activities, including boating and fishing, while E. coli and other water quality concerns are addressed.
"Monthly water quality averages at Tempe Town Lake typically pass surface water standards with flying colors," said Dr. Rick Amalfi of Aquatic Consulting. "Runoff like this, especially record runoffs from two rivers, brings with it everything from upstream. It will take time for that water to pass and the bacteria level to reduce below the event threshold."
The closure and race format change are temporary, but they illustrate how even a boon for the water supply can carry short-term costs for the community. SRP said it expects releases to continue returning to normal as the reservoir system absorbs the historic inflows.