The normally dry Rillito River and Tanque Verde Creek have been flowing steadily in recent weeks even though Tucson has had no rain since a mere 0.01 of an inch on Jan. 24.
The shallow but persistent streams, fed by snowmelt from mountains, will help replenish much-needed groundwater, experts say.
“The slower flow you get from snowmelt does help with (groundwater) recharge,” said Suzanne Shields, director of the Pima County Flood Control District.
“It has more chance to soak in — infiltrating as it’s flowing because it’s going slowly,” as opposed to rapid runoff from heavy rains, Shields said. “This has been happening over several days. It’s not just a short event, ... this is very beneficial.”
Professor Thomas Meixner, a University of Arizona hydrologist, also sees recharge benefits from the continuing stream flow.
“Winter has been decently wet so far, and the amount of snow in the Catalinas means an extended runoff season in mountain streams,” Meixner said. “That should translate to above-average recharge.”
Meixner said he expects the stream flows and recharge to continue in the coming days and perhaps weeks.
“Essentially, infiltration and recharge on the Rillito is directly dependent on how long it flows,” Meixner said. “My guess is that the next two weeks will see pretty good flow.”
A stream that flows for weeks rather than days is a relative rarity in the Tucson valley — and many people have taken the opportunity to walk along, or in, the waters of Tanque Verde Creek and the Rillito.
Some have brought their dogs for a frolic in the flow.
One popular spot is along North Craycroft Road where Tanque Verde Creek and the Pantano Wash come together to form the Rillito.