Throughout 2020, Tucson Water will be finalizing its first long-range master plan in 15 years, described by Jaimie Galayda, a lead planner with the utility, as “a much more evolved approach to planning,” with “climate change definitely one of the scenarios.”

Called One Water 2100, the plan will integrate Tucson Water’s four primary water sources — surface water delivered through the Central Arizona Project (CAP), groundwater, reclaimed water, and rain- and storm-water harvesting — in a process that will require partnerships and planning with outside agencies such as the Central Arizona Water Conservation District for CAP water and Pima County’s Regional Wastewater Reclamation Department (RWRD).

“There are all these moving targets out there that are changing,” said Galayda at a Climate Tucson meeting in November, “especially when you’re talking 80 to 100 years into the future.

“We’re trying to manage our integrated water resources to adapt to all those possible future scenarios.”

As part of the planning process, Tucson Water is commissioning a series of technical papers, two of which deal directly with climate change. The first, said Galayda, will “set the stage for what is actually happening here” in terms of a changing climate. Another will lay out Tucson Water’s carbon footprint. Water utilities are among the largest users of electricity — water is heavy and it takes a lot of power to move it through pipes to faucets. “Tucson Water,” said Galayda, “uses half of the energy used by the City of Tucson. So when we do our carbon footprint, we’ll be doing half of the city’s [overall] operations footprint.”

All state water utilities are required to submit a drought response plan to the state every five years. With drought a normal occurrence in an arid environment, drought “is one of the impacts we already know,” said Galayda, adding that the utility plans for various known drought stages. “Drought has become synonymous with climate change for us.”

Going forward, Tucson Water will take its cues largely from the newly enacted Lower Basin Drought Contingency Plan (DCP). Signed into law in May 2019 by the seven states that rely on Colorado River water, primarily Arizona, California and Nevada, the DCP is a landmark agreement by all those involved to voluntarily reduce the water used by their combined current population of 40 million people. The drought that has plagued the Southwest region for nearly 20 years has drastically lowered the water levels of the Lake Mead and Lake Powell reservoirs.

Tucson Water will rewrite its drought response plan “to be aligned with the DCP and the lake levels,” said Galayda.

Within the long-range plan is an upcoming 10-year strategic conservation plan that will assess how much water the utility can conserve through its rebate programs “for things that reduce consumers’ water consumption,” said Galayda, including low-flow toilets and rainwater harvesting. Although the rebates have been in effect for years, Tucson Water has not identified ways to maximize water savings from the programs.

With the analysis, the utility can better determine a target amount of water that can be saved through these rebates. That calculation, said Galayda, will be incorporated into the master plan as water that can be banked as groundwater for future supply needs.