The ongoing discussions and conflict between the Environmental Protection Agency and Rosemont Copper over mitigation for the Rosemont Mine's impacts on surface waters date back months.

To read the latest on this issue, turn to our print edition today for its article on Rosemont's plans to buy land and water rights southeast and south of Tucson to compensate for the mine's negative effects on places such as Barrel Canyon at the mine site, and, a bit downstream, Davidson Canyon. The compensation plan is aimed at getting the U.S. Army Corps of Engineers to approve a 404-Clean Water Act permit, that would allow Rosemont Copper to build the mine in the Santa Rita Mountains southeast of Tucson.

Two earlier letters, one from EPA, one from Rosemont, lay out some other issues, particularly involving the mining company's plans to buy Sonoita Creek Ranch near Sonoita for a mitigation project.

On Jan. 25, 2013, EPA wrote a lengthy missive to the Army Corps that blasted Rosemont's mitigation plans. The company's plans were less extensive than they are today. They didn't, for instance, include the purchase of more than 1,100 acre-feet of water rights along Cienega Creek to be turned over to Pima County and the Tucson Audubon Society.

The thought underlying that purchase was that those water rights would be used in part to upgrade Cienega's streamside habitat downstream of Pantano Dam, where the creekside is now mostly desert vegetation.

But the letter did take a rather pointed shot at the company's planned purchase of the 1,200-acre Sonoita Creek Ranch and its water rights of nearly 600 acre feet. The ranch lies south of State Highway 82, about halfway between Sonoita and Patagonia.

In the letter to the Corps, EPA's San Francisco-based wetlands supervisor, Jason Brush, made the following points about the Sonoita Creek Ranch purchase:

  • The habitat creation that Rosemont was proposing for the ranch may not be ecologically sustainable. Among other things, the mining company plans to buy water rights to Monkey Spring, which lies just north of the ranch, and use its water to create about 115 acres of riparian habitat, including a 3,000-foot-long river corridor, with a five-foot-wide and one to two foot-deep channel. The water would be used to create a drainage feature and adjacent riparian areas.
  • Only 3.5 acres of that 115 acres could be considered water course miles that would be good enough to fall under the Army Corps' jurisdiction as "waters of the U.S."
  • The proposed plan wouldn't be self-sustaining, because it would largely rely on regulated releases of irrigation water, and it was unclear whether the amount of water proposed for release is enough to maintain the proposed channel and its adjacent riparian wetlands.
  • The aquatic habitat proposed for the ranch actually includes 112 acres of upland areas and isn't aquatic habitat.
  • It's not clear why Rosemont didn't propose a continuous corridor from the two ponds on the property to connect them to Sonoita Creek.

"Based on the information provided, we believe the proposed creation (of wetlands) at Sonoita Creek Ranch is unlikely to be ecologically successful and sustainable," as is required by Arny Corps rules governing mitigation plans, Brush wrote.

". . . The compensatory mitigation package . . . is grossly inadequate, fails to accurately assess the functional condition at the project site and mitigation site and fails to provide compensation for proposed project impacts," Brush wrote.

In reply, Rosemont Copper vice president Kathy Arnold wrote Brush on June 19 the following:

". . . Rosemont is working diligently with the Corps to revise and refine the compensatory mitigation package, in compliance with the Corps' and EPA's 'Final Rule for Compensatory Mitigation for Losses of Aquatic Resources, hereinafter referred to as the 2008 Mitigation rule."

Arnold continued that the company anticipates meeting the mitigation requirements by either establishing, or paying another party to establish, what's known as an "in-lieu-fee" project, or projects. An in-lieu project involves a company such as Rosemont paying another party for the privilege of operating a mitigation project such as the one for Sonoita Creek Ranch. In this case, Rosemont Copper has envisioned bringing in Arizona Game and Fish to operate the ranch project, since Game and Fish has wanted to buy that property to insure its preservation and upgrading for a number of years.

"As you know, the 2008 Mitigation Rule requires the Corps and project applicants to consider in-lieu fee payment options" before considering mitigation projects run by permit applicants such as Rosemont Copper, Arnold wrote. She added that at least two in-lieu fee sponsors are finishing their efforts to set up in-lieu fee programs and establishing such projects within the broader Santa Cruz River watershed

"Again, Rosemont is working closely with the Corps to ensure that the most appropriate mitigation package is developed . . ., and we anticipate that the ultimate mitigation package will more than offset project impacts to the aquatic environment," wrote Arnold, Rosemont Copper's vice president for environmental and regulatory affairs. "We look forward to providing additional details of this with EPA during our meeting this week."

Rosemont has indeed come up with another mitigation project: the purchase of 1,100 acre feet of water rights along Cienega Creek, as previously mentioned. EPA has so far rejected both these projects as mitigation plans. The Corps has not decided on either one, and negotiations among all parties involved continue.