Dragonflies, toads, roadrunners, snakes and kingfishers all found a home at the Santa Cruz River downtown while Tucson Water was releasing large amounts of water into that stretch.

Ecologists and other scientists were saying before the releases started in June 2019 that returning water to the long-dry river would make it a haven for wildlife.

Over the next eight months before releases were reduced, that’s what happened, said Michael Bogan, an assistant University of Arizona aquatic ecology professor.

Specifically, the river drew:

  • Forty-two dragonfly and damselfly species.
  • Three native toad species.
  • The checkered garter snake, native to the Southwest.
  • Water birds including the gray hawk, sandpipers, killdeer, kingfishers, herons and egrets. These included the great blue, green and black-crowned night heron and the great egret.
  • Also, roadrunners and towhees that thrive in the desert were doing better in the river than on dry land, Bogan said.

Bogan, who has been to the river every week since releases started, was excited by what he’s seen.

β€œWe thought it would take years for all those species to come back,” he said of the dragonflies and damselflies.

He’s not surprised Tucson Water had to cut back releases of treated effluent into the river. The cutback began last month, and could last until mid-summer, to protect an old landfill from leaching contaminants.

β€œI always approached this as thinking about it as an experimental or managed ecosystem,” he said. β€œI expected we would have to do a lot of tinkering.

β€œThe fact that the species came back so fast when we turned on the water makes me optimistic whenever we turn the water back on, that the wildlife will return.”


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Contact reporter Tony Davis at tdavis@tucson.com or 806-7746. On Twitter: @tonydavis987.