NAU Student Takes on Project to Install Campus Reclaimed Water System

Graduate Student/Program Coordinator Abigal Roanhorse

As part of her master of engineering project, Northern Arizona University student Abigail Roanhorse acted as a nexus between the City of Flagstaff and the university to study reclaimed water use on campus. The means of fulfilling a degree requirement, the project evolved into much more, with Roanhorse taking the initiative to get support and funding to organize a major NAU reclaimed water feasibility study.

Roanhorse got started on the topic when she consulted with Flagstaff officials while attempting to identify a suitable project to undertake. Randy Pellatz, Flagstaff assistant utilities director, told her the city was anxious to switch NAU from potable water to reclaimed water for turf and landscape irrigation. In fact, over ten years ago the city and the university collaborated on a study of NAU and reclaimed water use, but with limited results. The university was only able to hook up a relatively limited area.

NAU is the single greatest user of potable water in Flagstaff and consumes an estimated 154 million gallons per year to irrigate 72 acres.

Roanhorse saw interesting possibilities in a project that could provide the groundwork for installing a reclaimed water system at NAU. She submitted the idea of developing an NAU reclaimed water feasibility study to her advisor who approved it. The scope of the project was sufficiently broad and ambitious to require funding. Roanhorse's entrepreneurial skills were called into play.

She sought and received funding from Arizona Public Service, the City of Flagstaff and the NAU Business College. NAU Capital Assets and Services also contributed funds along with in-kind assistance. Her funding from the City of Flagstaff was in the form of a contract that she produce a report as a deliverable to the city. Her awards totaled $120,000, and her success at attracting funds enabled her to hire three students to help with the project. Her graduate student status broadened as she took on the role of program coordinator.

The feasibility study required that she conduct an inventory, provide a conceptual design of the proposed system and perform an economic analysis. The inventory phase of the program characterized water demand and pipe sizing. Further, the inventory included evaluating soil types, mapping the existing irrigation system and identifying and mapping trees, shrubs and flowers beds on campus.

The second phase was the conceptual design. Its objective was to minimize the number of connection points required to tie NAU's existing potable water irrigation system into the reclaimed water distribution system. Roanhorse says, "While doing the conceptional design we did the economic analysis because it is hard to do one without the other."

The economic analysis was important because it would provide Flagstaff with the information needed to determine its financial support of the project. Flagstaff will pay an organization to convert to reclaimed water if the city can recover the cost of replacing the system within a 10-year period by selling reclaimed water to the organization.

Phase IV evaluated the existing NAU irrigation system. Roanhorse says, "When I was doing the inventory I noticed how inefficient the irrigation system was. We hadn't considered that in the original proposal." Her evaluation verified the problems with the existing irrigation system.

Roanhorse says, "We determined for the city how much water each connecting point and each section of the university would consume. Also how much money the city could make by selling reclaimed water to the university and how much groundwater they would save." Roanhorse came up with a proposed reclaimed water system design that would convert 66 acres of irrigated area to reclaimed water, with an estimated 141 million gallons of potable water conserved per year. Her report was sufficiently detailed to convince city officials to spend the approximately $1 million to construct the system to bring reclaimed water to the NAU campus.

The city still comes out a winner since it is cheaper to pay for a reclaimed water system than to drill a new well at a cost of about $1.8 million. The city saves in other ways too. Shifting NAU to reclaimed water saves the city about $28,000 in energy costs since reclaimed water is cheaper to pump than potable water.

Her interest in wise and efficient water use in northern Arizona continued beyond the writing of the feasibility report. With seed money from APS, Roanhorse got involved in fund raising to interest donors to contribute to xeriscaping the NAU campus and improving its irrigation system. Her funding also supports student participation in this ongoing endeavor.

Also Roanhorse received funding from the University of Arizona's Water Resources Research Center through section 104(b) of the Water Resources Research Act to conduct a workshop for water managers in northern Arizona. The workshop focused on turf and landscape water savings in northern Arizona, using both potable and reclaimed water. Over 50 professionals from the City of Flagstaff, NAU, the Navajo Nation and Sedona attended the event. Vendors of water and irrigation products also helped sponsor the workshop.

Roanhorse transferred to the UA and is a PhD student in the Department of Agricultural and Biosystems Engineering. She can be reached at Abigail.Roanhorse@NAU.EDU

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