The US Clean Water Act regulates the discharge of pollutants into “navigable waters”, which are defined as “the waters of the United States, including the territorial seas”. However, the definition of “waters of the United States” (WOTUS) has been the subject of ongoing debate and legal disputes.
The US Environmental Protection Agency (EPA) and Army Corps of Engineers issued rules in 2015 and 2020 with considerably different definitions of WOTUS, reflecting the policy differences between the Obama and Trump presidential administrations. In 2021, the 2020 rule was vacated by the federal courts and the agencies returned to using the pre-2015 definition. Most recently, the agencies issued another rule that took effect on March 20, 2023, which is largely similar to the pre-2015 regime but with some modifications.
Given the uncertainty surrounding the WOTUS definition, Hudbay conducted an independent study in Arizona to assess whether any of the waterways on its property could potentially be classified as WOTUS. The Company studied the sediment and water quality in the washes and found that none of the historic mine workings on the property were impacting the Santa Cruz River, which is the nearest potentially relevant water body. Based on these studies, Hudbay is confident that none of the on-site washes are WOTUS under either the pre-2015 rules or the current (2023) rule.
We shared our findings and studies with the EPA and the Army Corps of Engineers and continue to engage with the agencies to discuss any questions or areas of concern.