EPA rips Rosemont’s wetlands mitigation plan as “scientifically flawed” and failing to comply with Clean Water Act

The U.S. Environmental Protection Agency has notified Augusta Resource Corp. that its wetlands mitigation plan intended to compensate for damage to streams and springs from its proposed Rosemont copper mine fails to comply with the Clean Water Act.

Augusta must obtain a Section 404 Clean Water Act permit from the U.S. Army Corps of Engineers before it can begin construction of its mile-wide, half-mile deep, open-pit mine on the northeastern flank of the Santa Rita Mountains on the Coronado National Forest southeast of Tucson, Ariz.

Last winter, Augusta submitted a mitigation plan to compensate for the loss of 7,000 acres of natural habitat and aquatic resources that would be destroyed by the Rosemont mine.

EPA sharply criticized Augusta’s mitigation plan in a Jan. 25 letter, calling it “scientifically flawed”.

EPA’s broad objections to Augusta’s proposal will likely require the company to make significant, expensive and time-consuming modifications to its mitigation plan.

Vancouver, B.C.-based Augusta is seeking state and federal permits to allow its Arizona subsidiary, Rosemont Copper Company, to build and operate the mine.

Despite EPA’s Jan. 25 warning, Augusta continued to tell its shareholders in its latest financial disclosure reports released on March 25 that it expected to have all permitting in place by June 30, with construction beginning by the end of 2013.

Augusta filed its permit application with the Army Corps in October 2011. The Corps has been waiting for the U.S. Forest Service to complete a Final Environmental Impact Statement for the mine project before deciding whether to issue the 404 permit.

EPA has veto authority over the Army Corps issuance of Section 404 permits and has informed the Corps that Augusta’s permit application is subject to high-level review in Washington. EPA Region IX’s San Francisco office has repeatedly raised serious concerns over the proposed mine’s impact on aquatic resources.

EPA’s Jan. 25 letter to the Army Corps included extensive comments on Augusta’s November draft of its Habitat Mitigation and Monitoring Plan. EPA provided a copy of the Corps letter to Rosemont Copper Co.

EPA said Augusta’s draft plan “would fail to fully compensate for the project’s impacts to regulated waters.”

The agency said it “remains concerned that substantial loss and/or degradation of water quality and other aquatic ecosystem functions are likely if the proposed mine is constructed.”

The EPA letter, written by Region IX Wetlands Office Supervisor Jason Brush, skewered Augusta for making fundamental errors in its draft plan.

“The methods used to assess aquatic functions at the project site and proposed mitigation sites are scientifically flawed, and therefore fail to adequately identify and quantify those functions. This fundamental error is then compounded by the attempt to establish appropriate compensation ratios. The most significant issues are:

• The failure to fully assess direct, indirect and cumulative impacts from the proposed project.
• The functional assessment methodology does not provide any meaningful assessment of the function of ephemeral systems across the proposed project and mitigation sites and significantly understates the function of impacted waters; and
• The habitat creation proposed at Sonoita Creek Ranch may not be ecologically sustainable and may not result in jurisdictional waters.”

EPA noted that the mine would impact 1,364 acres of riparian habitat and adversely affect three different types of “Special Aquatic Sites” including wetlands, sanctuaries and refuges, and riffle and pool complexes.

The mine project would also directly or indirectly impact two water systems designated by the State of Arizona as “Outstanding Arizona Waters”: Davidson Canyon Wash and Cienega Creek.