As Ben Lomeli walked toward the Santa Cruz River last Wednesday morning, he stopped in front of a blue piece of fabric – cast aside, covered in dirt, sitting by the riverbank.

“Ball cap,” he observed, peering down.

Lomeli, along with Connie Williams, have both spent years with the Friends of the Santa Cruz River – working to preserve the body of water and its riparian habitat. But last week, they were looking for something less pristine: trash.

“Good stuff,” Williams said, peeking down at the litter by her feet. “I mean, not good stuff.”


Connie Williams bends down to examine a pair of pants strewn near the river.

On May 25, the Sonoran Institute, a conservation nonprofit, kicked off a study of the litter that often piles up in the Santa Cruz River near Tubac and Tumacacori. Luke Cole, the associate director of the institute’s Santa Cruz River Program, led a small group of volunteers beneath the Tubac Bridge, the sun growing hotter over the sandy riverbank.

“This is going to be a little bit of an art form,” Cole told the group as the river bubbled nearby.

Marking a sample area with measuring tapes and flags, the researchers carried clipboards, meticulously observing what they found: an e-cigarette cartridge, still filled with liquid. An empty food container from Wendy’s. A tire, half-buried into the dirt floor.

While some findings were fairly ambiguous – a styrofoam cup, a brittle, broken piece of plastic – others’ origins were a bit more obvious. Like food packaging from Wendy’s – likely not from Mexico, Lomeli noted.

For now, researchers and volunteers are simply documenting and analyzing the litter that washes up in the river area. Understanding what makes up the trash, Cole said, can better allow researchers to pinpoint where it’s coming from and develop possible solutions.

River river

Madeleine Oliver steps across the Santa Cruz River.

Pile-ups and pollution

In some cases, garbage is so plentiful in the Santa Cruz River that it can shift the river’s path. North of Tumacacori, Cole said, that’s a reality.

There, “the trash has just built up,” he said. “Up against the banks, up against the vegetation. To the point that it’s changed the flow of the river.”

But the pile-ups pose an even more alarming threat to the river’s local ecosystem, Cole added. The river is home to a variety of land and sea species – from coyotes, to elf owls, to glider dragonflies, according to the institute.

In recent years, the river’s flow in Santa Cruz County has strengthened in certain areas. That’s due to the addition of effluent – treated sewage water – flowing into the river near the Nogales International Wastewater Treatment Plant.

That revitalization has yielded results, according to the institute. By 2015, a small endangered fish – the Gila topminnow – returned to the river ecosystem after virtually disappearing for years.

The trash that tumbles into the river, Cole said, undermines those conservation efforts.

“Those are hundreds of millions of dollars’ investments to make that water clean, where we’re able to see the return of a lot of the native, and endangered, and pollution-sensitive fish,” he said. “Then you just throw a bunch of trash on top of it.”

What’s more, he added, chemicals from certain materials can seep into the river water – a vital drinking source for native species.


Luke Cole of the Sonoran Institute prepares to measure a sample area.

A recent study conducted by the University of Arizona estimates that ecotourism rakes in millions for the county – $31.1 million in 2019 alone.

“We have all of this intense, deserved ecotourism around birds around dragonflies,” Cole said.

River pollution, Cole said, could threaten that, too.

Tracking trash

A similar waste assessment project, also headed by the Sonoran Institute, is already underway in Tucson, where the riverbed snakes through the city before reaching Marana. In the Tucson study so far, researchers noticed large proportions of food packaging and cups making their way into the river.

In both projects, researchers and volunteers will qualify and document litter in the first year-long phase. In the second phase, they’ll begin studying the quantity of trash through randomized samples.


Connie Williams unearths a pair of pants near the river.

In the past, Cole worked with the municipality of Washington, D.C. – using the same methodology to survey litter. Eventually, that led to solutions including a system that trapped aquatic trash.

However, there’s no one-size-fits-all answer for reducing waste in a river. That same solution might not work for the Santa Cruz, due to its notably high flow during the monsoon season.

Still, he contended, studying the area is a start – something that could lead to, among other things, education for residents whose trash may be making its way toward the river.

But for now, litter remains. And that, Cole added, “is shooting ourselves in the foot.”

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