The Army Corps of Engineers denied a construction permit for Alaska’s Pebble Mine project to proceed in accordance with the Clean Water Act (CWA).[1] Excavation of Pebble Mine — a sprawling depository of gold, copper, and molybdenum — would discharge fill material and dredge into U.S. waterways.

The project’s developers applied for a permit under the CWA, requiring the Army Corps to assess the project’s potential impact on nearby bodies of water. When project-produced dredge and fill threaten unavoidable adverse impacts on waterways, projects may not proceed without appropriate mitigation measures.

In reviewing the Pebble Mine developer’s plan, the Army Corps weighed the project’s cumulative environmental impact against proposed mitigation efforts. It determined that the project would “cause unavoidable adverse impacts to aquatic resources which would result in Significant Degradation to aquatic resources.” Subsequently, the Army Corps denied the permit because the public’s interest in halting the project outweighed the project’s benefits.

The Army Corps’ decision may prompt yet another court challenge to the CWA’s permitting requirements. A similar dispute arose in May when the Ninth Circuit enjoined the Army Corps from allowing the Keystone Pipeline project to proceed under Nationwide Water Permit 12. Project developers must address fully and effectively whatever mitigation efforts they plan to use against a project’s adverse environmental impacts. As the Pebble Mine project shows, a project — despite yielding vast and valuable resources — can fail without a compliant mitigation plan.

The CWA proves to be an ever-changing area of the law, so stay tuned for additional claims challenging the CWA’s permitting requirements, many of which have national impact.

[1] Letter from David S. Hobbie, Chief, Regional Regulatory Division, Department of Army, to James Fueg, Pebble Ltd. Partnership (Nov. 25, 2020),