Santa Cruz River Coming Back to Life – 09.09.2011

“We had a wake-up call in 2005 when there was a massive die-off of native cottonwoods and willows along eight miles of the Santa Cruz near Rio Rico,” said Emily Brott, Southern Arizona project manager for the Sonoran Institute.  Brott leads the Institute’s engagement in innovative water harvesting, river restoration and water policy initiatives in the bi-national Santa Cruz River watershed.  “No one knew why hundreds of trees were dying and fish had all but disappeared from the area.  We knew we had to act.”

Five years ago, the Sonoran Institute joined with several other groups, including Friends of the Santa Cruz River and the National Park Service, to track the health of the river in an effort to anticipate and help prevent future problems.  A Living River: Charting the Health of the Upper Santa Cruz River, the third in a series of reports, tracks the 2010 water year and compares current findings with those from prior years, providing a clearer picture of the River’s evolving health. Key findings include the following:

  • Water quality has improved significantly since the upgrade of the Nogales Waste Water Treatment Plant in 2009, including lowered nitrogen levels and higher oxygen levels.
  • Fish are returning to the area: in 2008, only 2 indigenous Longfin Dace were found; in 2010, more than 1,800 fish were found, including 600 Dace.
  • Heavy metals and E. coli levels remain a challenge; and
  • Water infiltration has likely increased due to reduced nutrient pollution.

“We hope that with such improved water quality, other native fish like the endangered Gila Topminnow might be washed down with the rains from where they live upstream and find themselves able to survive in this habitat,” Brott said.

Scientists are still studying the impact of treated wastewater, or effluent, on the ecosystem. But, as the partners work to track the River’s health, they are mindful of its role in the region. “The Santa Cruz River is central to our history and culture, providing drinking water for millennia of inhabitants and support for vegetation that cools our region and cleans our air,” said Jen Parks, president of Friends of the Santa Cruz River.  “It has a major impact on our quality of life every day, providing habitat, wildlife corridors, and exceptional recreation opportunities. This is why our team of volunteers has devoted so much time over the past 20 years to tracking and working to protect its health.”

Visit the Sonoran Institute website at to download the report, view comparisons of data from previous years, and read about other project updates.