In 2019, the USGS began studying the baseline water-quality of selected transboundary rivers in the Pacific Northwest. These studies are designed to characterize current water-quality conditions so as to facilitate future assessments of potential impacts related to upstream mining activities. Mining operations can have consequential adverse impacts on river health and watershed viability, prompting scientists to engage in long-term studies of downstream water quality. Many policymakers hope that deep studies of river ecology related to mining will reveal possible challenges just water pollution or ecological degradation and offer solutions to ensure clean rivers or safer mining operations in target areas.