Once the water is diverted at Pantano Dam, the landscape along the Cienega Creek Natural Preserve changes as the water flows through an underground pipeline to the nearby Rancho del Lago golf course in Vail. Only a little makes it over the dam.

A dam southeast of Tucson separates two biological worlds: a lush one to the south, where water flows, and a barren one to the north, where it doesn’t.

A similar contrast divides two ponds on a ranch west of Sonoita, one surrounded by ash trees and the other largely devoid of vegetation.

Places like these are at the heart of Rosemont Copper’s $25 million package of planned land and water rights purchases, intended to offset environmental impacts of its proposed, $1.2 billion open pit mine in the Santa Rita Mountains.

Mitigation plans for Cienega Creek and Sonoita Creek Ranch offer the promise of what company officials call “environmental lift.” Ideally, water freed up from commercial uses would restore landscapes that are now far less verdant than they could be.

But both mitigation plans are controversial — so much so that Pima County, the Environmental Protection Agency and the Army Corps of Engineers are unwilling to endorse them.

At Cienega Creek southeast of Tucson, Rosemont would buy water rights to reflow the dry streambed downstream of the Pantano Dam. The mining company calls this a once-in-a-lifetime chance for Pima County to restore the creek, which is part of its Cienega Creek Natural Preserve.

Rosemont also would buy the privately owned 1,200-acre Sonoita Creek Ranch about halfway between Sonoita and Patagonia. Additional water rights would restore wetlands, streamside riparian groves and native fish.

Both purchases are part of a larger Rosemont-proposed mitigation package that calls for buying 4,500 acres and 1,700 acre-feet of water rights on properties up to 100 miles apart. The company has either bought the land and water rights outright or paid for options to buy them in the future.

“Our plan is to avoid impacts where we can, minimize impacts where we can’t avoid and mitigate where the impacts can’t be avoided or mitigated,” Rosemont Copper Vice President Jamie Sturgess said during a recent briefing in Tucson to unveil the plan.

Local supporters of the mine such as the Tucson Metropolitan Chamber of Commerce and the Southern Arizona Leadership Council hail the mitigation plan as a sign that Rosemont is a good corporate citizen.

But county officials, the Environmental Protection Agency and environmentalists are wary. They say the slowly drying Cienega Creek proposal doesn’t carry enough water to make all the restoration plans work. And Sonoita Creek Ranch is in a different watershed from the washes the mine could damage.

The Army Corps of Engineers, which must decide on a federal permit for the mine, hasn’t weighed in.

Mitigating mine impact

The proposals are intended to mitigate the mine’s impacts on surface waters at and downstream of the mine.

Mitigation is required for the company to obtain a Clean Water Act permit, which it needs to build facilities and place mine tailings and waste rock in washes and to discharge sediments and other materials into them.

The Forest Service, in its latest draft of a Rosemont Mine environmental impact statement, says the projects would also help endangered species that otherwise would be harmed by the mine. But EPA, the county and the Arizona Game and Fish Department are concerned there won’t be enough money to manage either project over the long term.

In an interview, EPA wetlands official Jason Brush said the agency’s objections stem from the project’s potential impact on “two outstanding resource areas,” Davidson Canyon and Cienega Creek. The EPA fears they could be seriously damaged by the mine, although the Forest Service report said computer models indicate that’s unlikely.

“The challenge for the mine is that they’ve done a lot to minimize the impacts of their project. We applaud them for that,” Brush said. “There’s still a significant impact.”

Rosemont’s Sturgess said the company understands that questions still loom, and is willing to do what it takes to answer them.

“I’ve never known EPA to not want more study on everything,” he said. If more steps are required, “that is a cost of doing the program.”

Cienega Creek

The Cienega Creek project’s potential and risks become clear when standing just upstream of the small, concrete Pantano Dam.

There, the county’s Cienega Creek Natural Preserve shimmers with cottonwood and willow trees, their bright green leaves towering 50 or more feet high, and their branches bowed over the creekbed.

Birds flit through the treetops. Tall stands of green grass cover the creeksides. A flowing stream at least 5 feet wide runs through the middle of the creekbed.

Below the dam, the streambed is a mudflat, at best. Most of it is dry. Saguaro, ocotillo, prickly pear and barrel cacti stand next to a scattering of cottonwoods and willows on the streambanks.

The source of this stark contrast is a small metal grate atop the dam. Most of the creek’s water pours into it and flows via underground pipeline to the neighboring Rancho del Lago golf course in suburban Vail. Only a trickle makes it over the dam and down 15 or 20 feet toward the virtually dry creek bottom.

As part of its mitigation plan, Rosemont Copper would buy 1,122 acre-feet of water rights (enough to serve more than 3,000 homes a year) from the golf course owners and transfer them to Pima County and the Tucson Audubon Society.

The theory is that once the water rights are in public hands, likely not until 2016 or later, the county could discharge water downstream of the dam, potentially creating a new riparian corridor of cottonwood and willow.

“We believe this is one of our offsite gemstones,” said Rosemont’s Sturgess, a senior vice president for corporate and government affairs.

In its latest draft of the final Rosemont environmental impact statement, the U.S. Forest Service said the company’s plan to retire a groundwater well near Cienega Creek also would help the creek’s restoration.

Downstream of Pantano Dam, new riparian habitat would replace habitat lost closer to the mine, the service said. And the company would create a $2 million Cienega Creek Watershed Conservation Fund to help restore and manage the watershed.

But in its comments on the environmental impact report, the Army Corps asked the Forest Service to delete statements that the project would replace riparian habitat and restore or maintain surface waters, saying, “There is no documentation that this statement is correct.”

County and Arizona Game and Fish Department officials also said in comments to the Forest Service that the $2 million figure for the Cienega restoration fund wouldn’t begin to do the job.

Plus, due to the Cienega area’s geology, it’s not clear how much water could actually be used to restore the creek, added Rob Leidy, an EPA ecologist in San Francisco. The bedrock beneath the Cienega Creek-Pantano Dam area is fractured and water is leaking out, Leidy said. New water could seep deeply into the aquifer without restoring vegetation.

The EPA praised Rosemont Copper for proposing to turn the Cienega water rights project over to the county and the Audubon Society. Because the mitigation plan would be managed and monitored by an outside sponsor, “there is more accountability,” said Elizabeth Goldmann, a physical scientist in EPA’s San Francisco wetlands office.

But, ”first and foremost, you must have a solid compensation plan that results in offsetting the project impacts and has a high chance of success, that is sustainable,” Goldmann said.

The county says the creek needs to carry 700 acre-feet a year for the restoration plan to work, but its flow has been steadily declining and averages about half of that, or 360 acre-feet a year, County Regional Flood Control District Director Suzanne Shields and Tucson Audubon Society Director Paul Green wrote in a July 31 letter to the Corps. Expected climate change also will make mitigation tougher, the letter said.

Objecting on the grounds that the creek typically doesn’t carry enough water “appears like it’s a setup,” Rosemont’s Sturgess said. “They’re saying that because the 700 acre-feet isn’t there, it fails and the project has no value. They’re setting an impossible goal.”


As Sturgess and other Rosemont officials and consultants drove into Sonoita Creek Ranch last week, he was effusive about the property’s thick grasses and tall shrubs, calling it “the jewel of the desert.”

A consulting biologist, Greg Williams of Westland Resources Corp., said of the ranch, “There’s not a higher-functioning habitat in Southern Arizona.”

From Arizona 82 about halfway from Sonoita to Patagonia, all you can see are thick grasslands, hay fields and stands of mesquite and other trees. Out of sight from the road are two spring-fed ponds connected by a stream and irrigation ditch.

The ranch has been at the top of Game and Fish’s list to buy, Sturgess said, to maintain as wildlife habitat rather than subdivided into ranchettes.

The larger pond – oblong-shaped and covering several acres – is surrounded by ash and other trees. It is stocked with non-native bluegill, bass and catfish, but Sturgess said he foresees replacing them with native fish.

A neighboring spring provides the ranch with 590 acre-feet a year of water rights, used for irrigating crops and watering grass for livestock. The area also has forested wetlands and riparian areas, semi-desert grasslands and washes.

“The first time I drove down that road, I looked down on the ag fields and the full, verdant growth and said to myself, ‘Wow, that’s the prettiest place,’ ...” Sturgess said. “I pictured a vineyard. Now, we’re putting it into conservation use.”

The second pond is smaller and narrower than the first, but Sturgess said that when the restoration is complete, “This one will look like the other one,” larger and grander.

The company’s plan is to buy the ranch and turn it over to the Arizona Game and Fish Department to manage, under a similar outside sponsorship as the company envisions for Cienega Creek. Covenants or conservation easements would forbid real estate development and restrict livestock grazing.

The ponds, now containing exotic bullfrogs and fish, would be renovated for native fish, the threatened Chiricahua leopard frog and the endangered Huachuca water umbel. Spring water now used to irrigate 119 acres of fields would be used to establish more wetlands and riparian areas.

The EPA said it recognizes the ranch’s conservation value, but it’s concerned whether proposals to create and improve wetlands are feasible. It also fears the site is too far and disconnected from Davidson Canyon and Cienega Creek to make up for the mine’s damage to those areas.

In response, Rosemont’s Sturgess said the EPA isn’t being consistent. Previously, the agency told Rosemont it believes several parcels it’s bought near Davidson Canyon won’t qualify as Clean Water Act mitigation because they are just downstream of the mine and could be damaged by the mine cutting off their water source. Now, he said, “EPA is saying this ranch doesn’t qualify because it’s in a different drainage from the mine.”

The Army Corps has suggested the Forest Service remove references to the ranch from its final Rosemont environmental impact statement, partly because no outside sponsor has agreed to take over ranch operations. Also, there is no scientific determination the mitigation plan would work, the Corps said.

In a written response to questions from the Star, the Corps said it has not completed its evaluation of Sonoita Creek Ranch as a possible mitigation site.

What will it spend?

Just how much is Rosemont willing to spend to get its project approved?

“We like to look at things from the rule of 25s,” company executive Sturgess said after his briefing late last month. “Rosemont has spent about $25 million to acquire the mine property and associated real estate for our wells.

“We presented today about $25 million worth of real estate and water rights. We have a $25 million community and social endowment trust fund we’ll use for social and community interests over the life of the mine. Augusta Resource, our parent company, is committed to spending $25 million to build a recharge pipeline for Central Arizona Project water.

“Are we prepared to do more? It depends . .. but ... some people will never be satisfied. There’s never enough,” Sturgess said. “Let’s look at our goals, and our mitigation proposal in proportion to the level and scope of impacts. We’ve accomplished that — probably more than once-over.”

Even if the Army Corps approves a Rosemont mitigation plan, that doesn’t mean it will get its Clean Water Act permit.

First, the Corps must determine that the mine proposal isn’t contrary to the public interest and that it complies with federal Clean Water Act rules.

The Corps can’t decide until 30 days after the Forest Service publishes its final Rosemont environmental impact statement.

The EPA has veto power over the Corps’ decisions on Clean Water Act permits, but it seldom uses it.

Late last month, in an interview, EPA officials repeated past statements that unless mitigation and other issues are resolved, Rosemont could be referred to the Council on Environmental Quality in the White House for final action.

What would happen after that, nobody knows.

Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746.