Infrastructure improvements highlight city’s water sustainability strategy

(Sierra LaDuke/DD)
(Sierra LaDuke/DD)
A key point in Phoenix’s strategy for water sustainability is rehabilitating old pipelines, which a city official said would cost between $14-15 billion. (Sierra LaDuke/DD)

Updating aging infrastructure will be a key part of the city water services department’s strategy for improving water sustainability, according to city officials.

Kathryn Sorensen, director of the Phoenix Water Services Department, told City Council on Nov. 10 that the cost to replace degrading infrastructure, based on a rough estimate, was between $14-15 billion, $11 billion of which was needed solely for pipelines.

Sorensen said Phoenix’s water infrastructure situation is unique.

“When it comes to water infrastructure, specifically pipelines, we have a relatively spread-out service territory,” Sorensen said.

The Phoenix Water Services Department covers 540 square miles, with around 7,000 miles of pipelines — about the same number of miles as the Los Angeles Department of Water and Power, which serves more than 2.5 times the number of people.

A large part of the water distribution system is almost 50 years old and will need to be replaced with newer, stronger pipes in the near future. In the early 2000s, Phoenix started a program to identify and repair smaller, aging water mains, according to Deputy Water Services Director Aimée Conroy. The city has inspected 69 miles of its 140 miles of transmission main –- the pipes that carry the vast majority of fresh water to the city — and inspections on the rest of the line are expected to be completed by 2026.

Conroy said the programs were important to help prevent water main breaks, thereby saving money and water.

“The goal of both of our programs is to maximize the life of our system, and to rehabilitate our system prior to having a major break, such as the 2006 Superior Ave water main break,” Conroy said. The 2006 Superior Ave water main break was caused by a leak from an aged water main that failed, damaging a nearby contractor’s equipment shed, digging a massive hole, and releasing tens of thousands of gallons of fresh water.

Conroy said the city currently replaces around 25 miles of pipeline a year, but based on an average lifespan of 75 years for the pipes, the city needs to replace 95 miles of pipe a year.

Phoenix’s strategy also included how the city would handle droughts in the future, to keep providing water to Phoenix’s residents. Clifford Neal, a water resources management adviser for the city, said Phoenix is currently experiencing a moderate drought with a strong El Ninõ expected this winter. The Salt and Verde River Watershed, which fills more than half of Phoenix’s water needs through SRP, is expected to rise above normal levels of precipitation this winter. Currently, the reservoir is sitting at around 50 percent capacity, he said.

The Colorado River Watershed, which provides Phoenix with the rest of its water, is also expected to rise above normal levels of precipitation this year. There is no chance of shortage for the Colorado River Watershed in 2016, although Neal warns there is an 18 percent chance of shortage in 2017 and 52 percent chance in 2018.

Even with a shortage in 2017 and 2018, there will be minimal impact on the city, and none on the average resident. Agricultural demands will be impacted slightly though, by a decrease in water.

The city would also halt recharging stations for the watershed where excess water is pumped into the ground for later use during times of drought or greater need.

Neal said he supports Phoenix’s efforts to conserve water and decrease usage.

“The city has been working for decades on water sustainability and resiliency,” Neal said. “We have developed systems to use surface water sources to save fossil water from underground for a time of heavier drought, and we have created a culture of conservation.”

The number of gallons used per day per person has dropped 30 percent in the past 20 years because Arizona residents have started to embrace the desert more and convert their turf yards, going from 80 percent turf yards to only 15 percent in the past 40 years. High efficiency appliances are also to thank, Neal said.

The city currently stores around 19,456 acre-feet of water underground through SRP. In 2016, however, Phoenix is planning to store around 35,000 acre-feet of water, supplying the city as needed.

SRP was unavailable for comment regarding the increase of underground water storage planned.

A proposed rate increase for water by 3 percent and wastewater by 2 percent was also announced.

Phoenix has the fourth-lowest water and wastewater rate among the other top 20 cities in the United States, even after the proposed rate increase, Conroy said.

There had been annual rate increases from 1994-2013, and within that time, the Phoenix metropolitan area grew by 54 percent. The city has been able to coast on the saved fund balances, so that a rate increase has not been necessary, according to Denise Olson, acting chief financial officer for Phoenix.

District 1 councilwoman Thelda Williams reminded the council of that decision to draw down the reserves and make it so that residents didn’t have to experience a rate increase.

“This council made a decision not that many years ago that we would take down the reserve in lieu of raising rates, and I want the council to understand that the consequences have come due,” she said. “It is time to pay the piper.”

Olson said the city would need to implement a rate increase to keep Phoenix’s AAA bond rating, and be able to provide safe drinking water to residents.

“Going forward, we need to show we are willing to invest in this system to maintain reliability and safe drinking water,” Olson said.

She said bills will increase an average of $1.60.

Contact the reporter at Kmlane5@asu.edu.