C.C. Cragin Reservoir: Fire-threatened reservoir a marvel of water-storing technology

C.C. Cragin Reservoir: Fire-threatened reservoir a marvel of water-storing technology
Published
May 3, 2018

Sometimes, events come at you fast.

On Thursday, April 26, a senior water-rights analyst for Salt River Project, Sharon Morris, presented a scheduled tutorial on a unique reservoir in the pine country of northern Gila County for an assembly of Arizona Department of Water Resources employees.

In addition to a great many fascinating details about the reservoir’s history since it was completed in 1965, the analyst offered this sober note of concern:

“It is susceptible to catastrophic forest fire,” she said.

That observation quickly became a premonition.

Scarcely 24 hours later, Arizona media were reporting that the reservoir -- the C.C. Cragin Reservoir, a 15,000 acre-foot facility in a densely forested watershed – was near the ignition point of a human-caused wildfire. As of mid-day Thursday, May 3, the “Tinder Fire,” as it became known, had burned through more than 12,000 woodland acres.

The apparent result of careless campers who failed to extinguish an illegal campfire, the Tinder Fire ignited a mere mile and a half northeast of C.C. Cragin. Through mid-week, strong winds were blowing the fire away from the reservoir, but in the path of numerous woodland communities.

This April 29 aerial photo provided by the US Forest Service shows a wildfire burning in north-central Arizona.

(For up-to-date information about the Tinder Fire, as well as other conflagrations around the State, the Arizona Department of Forestry and Fire Management recommends InciWeb, a public website providing information about fire evacuations or road closure notices, fire size and containment numbers, pictures, maps, and other information.)

Though just 21 percent full following a historically dry winter, the reservoir, said Morris to her ADWR audience, typically is considered “very productive” thanks to its position in a moisture-heavy sweet spot atop the Mogollon Rim in Coconino County east of the mountain resort communities of Clints Well and Happy Jack.

This year, however, conditions at Cragin have proved so dry that SRP chose not to run the reservoir at all this summer.

“We can run it,” said Morris. “But we run into operational risks, so we have agreed not to run the reservoir this season.” For a time, the U.S. Forest Service even closed roads leading to the reservoir. While they since have re-opened (pending the outcome of the Tinder Fire), boat ramps on the reservoir have been closed for the season.

The town of Payson and nearby communities have invested considerably in recent years on infrastructure necessary to deliver C.C. Cragin water, located 25 miles north of town. By agreement with SRP, Payson has a right to just over 27 percent of the reservoir’s productive capacity, or about 3,000 acre-feet per year.

Originally known as the Blue Ridge Reservoir, the facility was built by Phelps Dodge, which used water from the Black River at its Morenci mining operations in an exchange agreement with SRP for the Blue Ridge Reservoir’s water.

That exchange, which began in 1962, provided for the future transfer of the Blue Ridge Reservoir system to SRP in the event it no longer was needed by the mining company. As the company’s need for water credits decreased, the water exchange eventually ceased in 2002, and Phelps Dodge sold its land holdings in the area to SRP.

The most significant change in the reservoir’s operations began taking shape in 2004 with the passage of the Arizona Water Settlements Act by Congress. In addition to authorizing important tribal water settlements, the Act transferred ownership of the then-Blue Ridge Reservoir to the United States, as part of the Salt River Federal Reclamation Project. As a result, SRP acquired the reservoir in February 2005.

The Act allowed for changes in the beneficial uses of the water and specified that the reservoir’s water right was transferred to SRP for use within its service area. Up to 3,500 acre-feet per year would be made available for municipal and domestic uses to communities in northern Gila County. That region includes Payson, which secured its deal for Cragin water in 2008.

Including its 147-foot dam, the Cragin reservoir is a marvel of engineering.

A pumping station that houses seven 450 horsepower pumps, as well as one 150 horsepower submersible priming pump, draws water (at 33 cubic-feet per second) from the reservoir uphill into a 2 million gallon priming reservoir.

From there the water drains from the priming reservoir downhill over the Mogollon Rim to a three-megawatt hydropower plant located next to the East Verde River. That power is transmitted back to the pumping plant, providing power to the pumps while the Cragin water is discharged into the East Verde River, eventually flowing into the Verde River and on into the Valley.