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Project uses recycled wastewater to revitalize dry river, bring back wildlife

Project uses recycled waste water to revitalize dry river
Project uses recycled waste water to revitalize dry river, bring back wildlife
Posted at 4:25 PM, Feb 08, 2022

Once dry and desolate, this riverbed in southern Arizona has been given new life.

“The idea of bringing water back to the Santa Cruz River for Tucsonans has been around for about 100 years. That's when the Santa Cruz River stopped flowing because of overpumping of the aquifer here in Tucson for the agriculture that was going on here in the early 1900s,” John Kmiec, the interim director of Tucson Water, said.

Here in the desert, every drop of water counts.

“South of where we’re standing, this is what the Santa Cruz looked like…it’s dry. It's been like that since the 1920s almost continuously. It only responds for rain,” he explained. “If you want to see abundant life in the desert, just add water, and it's amazing what happens after that.”

So that’s what Tucson water did back in the summer of 2019 – by putting water back where it used to be as part of the Santa Cruz River Heritage Project.

“This is highly treated effluent from our regional wastewater treatment plant,” Kmiec explained. “Our daily flow right now is about 1,500 gallons per minute.”

“We had more than 400 people at about 110 degrees down in this riverbed when we turned this outfall on,” he explained.

The recycled water runs 24/7 into where the Santa Cruz River used to run, attracting people above and wildlife below.

“Just about every desert creature you can think of, you see down here,” Kmiec said.

It’s the sounds of this ecosystem that show the success of the project. Keeping track of the biodiversity here is part of researcher Michael Bogan’s job.

“This is basically how we collect it from the river,” Michael Bogan, assistant professor of aquatic ecology at the School of Natural Resources and the Environment at the University of Arizona, said.

“So we need to preserve them in ethanol and bring them back to the lab.”

Bogan said he noticed wildlife return right after the water was turned on.

“I immediately noticed dragonflies who had obviously flown in from some other water body somewhere in Tucson, golf course, pond, something like that. Flown in and not only had they found this brand new water that was only a few hours old, but they were already mating and laying eggs in the water. To me that was like seeing the birth of an ecosystem,” he said.

So his team, along with other groups, are keeping track of the species coming in.

“In most places because of either drought, climate change and drought that we’re in or because of human water withdrawals from dams or diversions, most places are drying up. So most of what we study is what happens when the water goes away. This is totally the opposite,” Bogan said.

“It’s a relatively small amount of water, yet it has a huge positive impact.”

Kmiec said the Santa Cruz River Heritage Project shows how to use water in a sustainable way to bring life back to the area for wildlife and for people.

“We see it as one of many. So we’re looking at other opportunities,” he said.

“We’ve done a lot of damage to the ecosystems so this is an example of trying to undo some of that damage,” Bogan said.