Statewide, Ore.— Warm water continues to be the top source of pollution in Oregon’s rivers and streams, according to the latest and most detailed report produced by the Oregon Department of Environmental Quality. The 2022 Integrated Report on state water quality, as it is called, has now been approved by the U.S. Environmental Protection Agency and becomes the official record of the current status of the state’s waters. Every two years, DEQ is required to analyze the condition of thousands of miles of Oregon waterways, using monitoring data provided by a wide variety of organizations and individuals, including the agency’s own measurements. The information is compiled in an interactive online map that allows users to pinpoint everything from small sections of rivers and streams, to lakes, coastal waters or entire watersheds, and learn what might be impairing water quality. “This information is crucial for public awareness and understanding of the condition of our rivers and watersheds,” said Connie Dou, DEQ’s Water Assessments Manager. “Oregon has some of the most scenic and pristine water in the world. But we also face some clear challenges to protecting water quality for fish, drinking water and recreation.” As in prior reports, the top four impairments continue to be temperature; dissolved oxygen; degraded aquatic insect communities, also known as biocriteria; and impairment from pathogens (E. coli). To compile the report, DEQ water quality staff pored through 7.6 million pieces of data from more than 3,000 monitoring stations. They looked at water temperature, presence of bacteria or other toxic contaminants, relative acidity, oxygen levels and other measurements of water health. If a section of river is deemed “impaired,” meaning it has too much of any of the above pollutants to fully protect aquatic life or drinking water, or allow for safe recreational use and fish consumption, it is placed on a federal list, known as the 303(d) list. Waters on that list are subject to additional environmental protections and clean-up plans. Dou praised the work of water quality staff who produced the report. “This is the most comprehensive look at the state or Oregon’s waters that DEQ has ever produced,” she said. “It represents tremendous staff effort and rigorous science that will serve the public.” DEQ also determined that low oxygen, also known as marine hypoxia, is a potential concern in Oregon’s coastal waters, but the data and DEQ’s current capacity to assess ocean conditions is insufficient to identify the water as impaired. DEQ has convened a scientific technical work group to assist in characterizing changing ocean conditions in future Integrated Report cycles. Working with this group, DEQ plans to outline an appropriate methodology for assessing the health of Oregon’s territorial waters.