PHOENIX — Col. Mark Toy, the U.S. Army Corps of Engineers Los Angeles District commander, presented the Chief of Engineers Award of Excellence for Environmental Design to the City of Phoenix and representatives from the District’s Arizona-Nevada Area Office, Archer-Western Contractors, Ltd., and Jacobs Engineering Group, Inc., for work done at the Tres Rios Environmental Restoration project, Phase II Flow Regulating and Overbank Wetlands, during a ceremony held Nov. 1 at Phoenix City Hall.
"In 2002, then-Major Toy came to work with the U.S. Army Corps of Engineers. I remember one of my very first trips was to Phoenix and we visited a demonstration wetlands project in the West Valley," he recalled. "I find it so wonderful to be back here now to see how that project has grown."
Toy, along with Rep. Ed Pastor and Phoenix Mayor Greg Stanton, gave remarks during the ceremony about the project.
"The Army Corps [of Engineers] does so much for the country and we certainly appreciate it," said Stanton. "We are certainly ahead of our time with this project."
Stanton went on to praise the project’s level of sustainability and highlighted how it makes use of effluent in ways that are beneficial to the environment. The Tres Rios Environmental Restoration Project evolved from an early proposal for advanced nitrogen removal of effluent discharged from the 91st Avenue Wastewater Treatment Plant into a large scale habitat restoration, environmental education, flood control and public recreation project.
The project took shape in the early 1990’s as a collaborative effort involving multiple stakeholders including the Corps, City of Phoenix, U.S. Bureau of Reclamation, U.S. Fish and Wildlife Service, Arizona Department of Game & Fish, City of Avondale, Gila River Indian Community, the Flood Control District of Maricopa County, and the Environmental Protection Agency. According to Stanton, the project treats effluent in a more natural way at one-tenth the cost of a wastewater treatment plant. He credits the idea for the wetlands to Pastor.
"You were sustainable before being sustainable was cool," Stanton said. "We, as a city, are way ahead of our time with this project."
The Tres Rios project is a portion of a chain of ecosystem restoration projects throughout the Phoenix metropolitan area that use available resources like treated effluent to restore riparian habitat along rivers that once flowed naturally through the "Valley of the Sun." During his university days, Pastor and his classmates looked at the decimated river systems and tried to envision a way to bring them back to a level usable by both the people and the wildlife in the area.
"At the beginning, people didn’t believe we could do this," Pastor said. "Now, they can see this project serves many purposes. It takes the water from the treatment plant, filters it naturally and restores it to the environment. It also offers flood protection to the community."
Treated effluent from the 91st Ave. treatment plant is pumped into the flow-regulating wetlands. The regular flow of effluent entering the system is between 15 and 120 million gallons per day, and the wetlands can support up to 450 mgd during storm events. As the water flows through the system, a second tier of water "polishing" removes total residual chlorine, ammonia, and whole effluent toxicity. "Polished" water passes through the wetland system over the course of several days before being discharged into the Salt River.
The Corps of Engineers, the City of Phoenix and other principles gathered in 2010 to dedicate the wetlands after completion of the initial project. In the intervening two years, bobcats, bald eagles, beavers, turtles and other wildlife have either made homes or visited the wetlands and overbank areas. More than 147 species of birds have been spotted and identified in the restored riparian corridor. Officials believe the renewed diversity and abundance of wildlife species should increase over the years. Toy said the level of cooperation required to complete the project is a par for the course for the Corps.
"Anyone familiar with the work our District has done knows this collaboration fits right into my motto emphasizing our dedication to ‘Building Strong and Taking Care of People!'" he said. "That commitment guides how we operate and how we ensure we keep faith with residents across our District."
The Chief of Engineers Awards of Excellence program dates to 1965 when it was first held as the Chief of Engineers Distinguished Architectural Achievement Awards with ten entries, for which two awards were given. Since that time, it has evolved to include landscape design, the environment and sustainability initiatives. The combination of disciplines supports the Corps’ commitment to implementation of Executive Order 13514, Federal Leadership in Environment, Energy, and Economic Performance.