A new wildlife ramp taking shape between the Tucson and Tortolita mountains will give rock squirrels, lizards, javelina, mule deer, mountain lions and other critters a safer way to navigate beneath one of Southern Arizona’s busiest highways.
The Santa Cruz River Wildlife Ramp, part of the Sonoran Desert Conservation Plan, is expected to be completed by June and will serve as a bustling freeway for desert animals to move safely — without darting across Interstate 10.
The ramp is located between Twin Peaks Road and West Avra Valley Road, adjacent to the El Rio Preserve and an abandoned underpass at I-10. A wildlife fence will funnel animals to the ramp, ensuring its use. It is the first phase of a wildlife corridor in the area.
“The wildlife ramp provides access to an area adjacent to an existing underpass that wildlife can use to cross under I-10,” said Jeff Gagnon, research biologist for the Arizona Game and Fish Department. “This is one of the few places along I-10 where wildlife can cross, and if future planning continues to allow wildlife movement on both sides of I-10, it can provide connectivity for multiple wildlife species between the Tucson Mountains/ Santa Cruz River and the Tortolitas and Santa Catalinas.”
The $3.5 million project, funded by Pima County Flood Control District tax dollars, includes a levee-modifying ramp, reinforced culvert, wildlife fencing and even a pedestrian bridge along the Loop, according to Nanda Srinivasamurthy, Pima County’s engineer and project manager. It is a rare double-duty innovation in infrastructure.
“Wildlife faces a lot of obstacles in being able to move as they need to find food, water, mates and new habitat,” said Jessica Moreno, conservation science director of the Coalition for Sonoran Desert Protection. “This wildlife ramp is designed to help animals to travel in and out of the river corridor while still doing that job of embankment protection.”
Construction crews work on a wildlife corridor and ramp along Interstate 10 near Avra Valley Road on Wednesday, April 15, 2025.
Other similar wildlife corridor projects in Pima County include the Oracle Road crossing completed in 2016 and the Tangerine Road underpasses completed in 2018.
This project is unique because it is designed to keep wildlife safe and keep water out.
“By modifying this levee to make the slope less steep, it allows the wildlife to cross over it and makes that connectivity a little bit easier,” said Camille Hall, Pima County’s community engagement manager.
Maintaining the levee’s flood control function while installing the ramp has been one of the most significant challenges.
“Flood control’s main mission is to protect people and property from flooding, so we’ve had to ensure the levee function is not compromised,” Hall said. “Maybe in the future, you might see more wildlife ramps working double duty like this one.”
Hall said that before construction began, a wildlife camera was set up to see what animals may take advantage of the wildlife ramp.
“It’s a wide wide variety spanning all sizes from the small rock squirrels to lizards or larger animals like javelina, mule deer and mountain lions,” Hall said. “We are hoping to see a lot of animals using the ramp and will actually be setting up a wildlife camera after construction so we can see what animals are utilizing that area.”
Additionally, ecological impacts were carefully considered before breaking ground.
“We were actually in the area trapping and relocating lizards and other small creatures in hopes to not only get a feel for what animals are there but also to minimize any risks to animals that might be in the area prior to construction,” Hall said.
To learn more, visit the Santa Cruz River Wildlife Ramp website and attend the Santa Cruz River Research Days. This free, bilingual event will feature talks specifically focused on the ramp on Wednesday, April 30.
“This project is one puzzle piece in a much larger picture, to help wildlife move freely through an established ‘wildlife linkage’ corridor,” Moreno said. “Another big puzzle piece you will be hearing about is a future wildlife bridge that connects this ramp to open space on the east side of I-10 and the railroad. But, that is another story.”
This story first appeared in Arizona Luminaria.
