Need Grows for Tucson CAP Reliability

Two strategies proposed

by Joe Gelt

Central Arizona Project reliability in the Tucson area was a major topic of discussion at a recent CAP Board meeting as water providers in the area consider the direct delivery of CAP water. To ensure the reliability of directly delivered CAP water during temporary outages a terminal storage or reservoir would be needed.

The direct delivery of CAP water and terminal storage are issues with which Tucson has had some previous experience, although with unexpected and unfortunate results. Recent developments are a new chapter in the Tucson CAP story

CAP reliability is becoming an important issue in Tucson with water providers considering the direct delivery of project water. Water providers northwest of the city are considering using their CAP allocation sooner than was anticipated; they are urging the construction of a reservoir. Tucson Water is considering the direct delivery of CAP but expects to rely on a recharge facility to provide terminal storage.

Tucson terminal storage in the Black Wash area was included in the original plans to bring CAP to Tucson. It became moot when Tucson decided to suspend direct delivery of CAP water. The decision had as much to do with politics as hydrology.

Tucson Water’s ill-managed effort to directly delivery CAP water to its customers in the early 90s is part of state water lore. The utility aborted the effort when customers complained of water resembling ice tea coming out of their taps. In 1995 a voter initiative was passed, the Water Consumer Protection Act, that prohibited direct delivery of CAP water to homes in the city, requiring instead that it be recharged.
Tucson Water is now considering various options that will determine its reliability needs. It options are to continue recharging and recovering CAP water or reactivate its water treatment plant to begin direct delivery. A third option combines the two strategies, with CAP water both recharged and recovered and directly delivered.

The city intends to gauge public sentiment about direct delivery through hearings, neighborhood meetings, opinion polls and focus-group sessions that will start in about six months. It confronts the challenge of wining over many citizens who were soured by the utility’s previous effort at direct delivery of CAP water
Whatever is eventually decided, however, the utility will not likely rely on a reservoir to ensure reliability. Its CAP allocation is now recharged and recovered at its Clearwater facility. Mitch Basefsky, Tucson Water spokesman, says Clearwater could provide the terminal storage the utility needs. He says, “The Clearwater facility would essentially be an underground reservoir. This would eliminate evaporative losses, and you would have more of a buffer in terms of water quality.”

Meanwhile the communities northwest of Tucson are feeling a greater sense of urgency about direct CAP delivery and terminal storage. Groundwater pumping in the area is taking a toll: in 2004, Metro Water’s wells dropped 5 to 13 feet, with some of its more productive wells dropping more than four feet annually over ten years. Oro Valley’s water table dropped 2 to12 feet in 2004; since 1999 it had declined at a 6.3 annual average.

As a result, northwest utilities expect to be using their allocated 30,000 acre feet of CAP water within ten years. They have formed a technical working group to study the issue.

The northwest water providers are Metropolitan Domestic Water Improvement District, Flowing Wells Irrigation District, Oro Valley and Marana.

Key decisions to be made include the type of treatment system to employ and the financing plan to adopt to pay for CAP. Marana’s $1,700 per home impact fee that is effective Jan.1 is to cover the town’s CAP cost. Oro Valley’s $300 home fee goes toward CAP costs.

It is expected that water bills will rise when CAP water comes online, although officials are reluctant to project exact figures without additional studies.

The northwest water providers will confront the same challenge Tucson Water faced when it inaugurated its direct delivery of CAP water to its customers: they will have to convince their customers that receiving more expensive, saltier and harder water is in their best long-term water resource interest.

An appealing selling point will be that the terminal reservoir providing backup for CAP direct deliveries also would serve as a recreational lake. A site has been identified, located near Interstate 10 and Tangerine Road; plans call for the 110-acre lake to include a beach, campgrounds, and a loop drive with picnic areas.
Basefsky says that the northwest water provider’s plans do not impact Tucson Water, “except to the extent that there will be competition for those federal dollars. If they are going to get money for terminal storage then we would certainly be in line to get money to pay for terminal storage using our Clearwater project.”

A CAP board member struck a wary note during the discussions. Noting Tucson’s wayward and at times contrary CAP commitment, Jim Hartdegen said that Tucson has vacillated on accepting CAP water for years and asked: how can CAP now be sure that if it agrees to a reliability feature, Tucson would not reject CAP water?

In response, David Modeer, Tucson Water director and CAP board member, stated, “The fickleness of Tucson on water has long passed.”