Thinning forest to protect Payson’s water

Even with a plan in place, intense drought, climate change and a feeble timber industry stand in the way. But officials believe the approach will help save another small part of Arizona’s forests.

“I’m more realistic than optimistic,” said Linda Wadleigh, U.S. Forest Service ranger for the Mogollon Rim Ranger District. “We have a sense of urgency.”

What’s planned for the forest

Two elk stand a stone’s throw from the road, watching an object in the distance move closer. As the Forest Service truck nears, they dart behind the trees.

At risk here are thousands of acres of forest, habitat for threatened species and water for residents of Payson. If all goes according to plan, officials will thin 64,000 acres of the forest using mechanical and hand thinning, as well as prescribed burns.

A coalition involving the U.S. Forest Service, Salt River Project and the U.S. Bureau of Reclamation and others moved forward in late July when officials signed the plan. The Cragin Watershed Protection Project was the result.

The goal isn’t to prevent fires altogether, but the coalition hopes to prevent catastrophic wildfires, the kind that burn thousands of acres and leave little in their wake. 

This year’s Tinder Fire, which destroyed dozens of structures and scorched more than 16,000 acres, nearly came in contact with the project area. An illegal campfire near the Cragin reservoir during Stage 1 burning restrictions sparked the fire.

“I don’t think we’ve ever had that much devastation or structure damage,” a Coconino County Sheriff’s Office spokesman said at the time. “Ever.”

Like much of the state, the Rim Country felt the effects of the dry winter, which raised fire risk and left less water for the reservoirs. The meager snowpack only exacerbated drought conditions. 

Gov. Doug Ducey in February requested increased funding for wildfire prevention as officials warned of a dire fire season closing in. Although the fire season in Arizona was less severe than many warned, the Tinder Fire was an exception.

When managed properly, fires can help restore the forest to its historic conditions, leaving it less dense and with less fuel for a catastrophic blaze.

“This is what pines used to be — open trees with stretches of grass,” said Mary Price, a U.S. Forest Service silviculturist. “When a fire does come through, it stays on the ground and does what it’s supposed to do.”

Clear the overgrowth, keep the forest healthy, protect the watershed and habitat. That’s what officials plan to do under the new plan.

Protecting the watershed

Two kayakers row across the little water that remains. They stop rowing for a moment. One draws her smartphone, snaps a photo and gets back to rowing.

From the parking lot above the reservoir, where water levels are sinking so low that the fish swimming are visible to the naked eye, pines dot the horizon.

“The forest itself is a precious resource for any number of reasons,” said Buzz Walker, special projects director for Payson’s water department. “We know after the catastrophic wildfires, it may never return. And if it does, it’s going to be in an altered state.”

A costly wildfire wouldn’t just pose a threat to the trees above the reservoir, it would also threaten the reservoir’s infrastructure and the quality of the water itself.

“You’re going to get ash, debris, sediment,” said Bruce Hallin, SRP director of water supply. “To the point where the water supply in that reservoir will be unusable for quite some time.”

SRP acquired the reservoir in 2005 and manages it, along with other dams, lakes and rivers across the state.

Some debris from a forest fire is light and would float on the water. That’s not much of a concern, because the water is going to be piped to a treatment facility, Walker said. Heavy amounts of sediment are a concern.

Sediment wouldn’t just float on the surface, it would sink to the bottom of the reservoir and displace its volume — filling a reservoir with something dense means there’s less room for water.

“That’s something we really worry about,” Walker said. “It makes the reservoir smaller because it starts filling up with dirt. It’s heavy … there’s not much chance we could push it out of there through the pipeline.”

Not only would it make the reservoir smaller, it would also tax the treatment plant. The plant uses a method called membrane filtration, which uses a physical barrier to keep ash from getting through. The system shuts down about every 18 minutes and goes into “backwash” to keep going, Walker said.

Wildfires create more of that ash and sediment and could cause the system to shut down every three to four minutes.

“We take our water from 140 feet down under the surface of the reservoir, so there will be some mitigation there because a lot of the debris from a forest fire floats,” he said. “(But) that’s something we really worry about.”

‘I’ve seen it lower only once’

Water levels in the C.C. Cragin Reservoir are low, hovering between 19 and 25 percent of capacity — not much higher than it was during this year’s Tinder Fire.

Its low levels are due in part to a bone-dry winter. Reservoirs depend on snow in the winter months to melt and gradually recharge water supplies, but the runoff season ended as one of the driest on record.

“When you don’t have winter, you don’t have snow,” Wadleigh said. “I’ve seen it lower only once.”

Cragin’s water is meant to supply Payson, a growing community with shrinking groundwater resources. Currently, the entire town is dependent on 43 groundwater wells. Starting next year, that’s going to change. 

“Next year, 75 percent of our water will be Cragin surface water,” Walker said. “If the groundwater’s not so good, you can use surface water and vice versa … hopefully Payson will have a forever water supply out of this. You can plan for shortage for either of them.”

But if a catastrophic wildfire strikes, planning may not be enough.

There could come a time when Payson uses all of its groundwater and all of its Cragin reservoir water. If the reservoir was suddenly imperiled, it would spell trouble for the town.

“When we grow into depending on that water supply on a daily basis, you can’t expel people from town when you lose your biggest resource, which is the Cragin reservoir,” Walker said. “Then you get into the Draconian water management, and nobody wants to live like that.”

There isn’t a lot of industry in Payson. Most of its residents are homeowners, Walker said. Without reliable water, many could be ruined financially.

“Their biggest asset is their home,” he said. “Where are you going to go if the forest is burning down? It’s a terrible domino effect.”

Using fire to prevent fire

Over time, Arizona’s forests have grown more dense. Too dense, experts say.

Healthy stands of trees have turned into crowded stands, piling up fuel for wildfires. Wildfires have burned more than 1.5 million acres of ponderosa pine forest over the last 20 years.

The culprit: Climate change and decades of fire suppression that took fire out of its natural, historic role. Fires behave differently than they did hundreds of years ago, when they would sweep into a forest every few years and clear out the brush.

Forests are now more dense, providing more fuel and creating conditions for a disastrous wildfire. 

“This area has become choked with trees,” Wadleigh said.

Forest managers are starting to turn to fire as a tool to naturally thin the forest, just like it did in centuries past. For some parts of the forest, it’s been close to a century since fire fulfilled its natural role.

“A lot of this area has not had fire in 50-plus years,” said Jeff Thumm, Mogollon Rim fire management specialist.

The trees in the forest, with fallen needles and other detritus, produce 30 to 50 tons of fuel per acre, compared to only about5 to 10 tons per acre historically, Thumm said.