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  • Michael O'Connor

ODEQ Ecological Assessment: Oregon Lakes Doing Better than Many other States

Oregon DEQ, August 12, 2022 Statewide, OR—The Oregon Department of Environmental Quality today released the 2017 Survey of Oregon Lakes , a statewide evaluation of the ecological condition of lakes and reservoirs from samples collected in 2017. Oregon’s report is part of the U.S. Environmental Protection Agency’s overarching National Lakes Assessment , and comes during National Water Quality Month . It also represents the first ever statewide dataset on toxics within Oregon’s lakes resources.

Results indicate the ecological condition of Oregon’s lakes is largely good, especially when compared to that observed nationally. Most lakes and reservoirs are in good condition for biological communities, like insects and zooplankton. In addition, DEQ found toxic compounds rarely exceed human health or aquatic life criteria. Overall, the majority of Oregon’s lakes are of high recreational value.

Because the sample sizes from earlier NLAs (30 sites in 2007 and 29 sites in 2012) were so small, DEQ was previously unable to make statewide assessments of lake conditions with confidence. However, in 2017, the agency developed a unique survey when it combined funding from the state and EPA to collect samples simultaneously for its Biomonitoring Program, which oversees sampling for the NLA, and its Toxics Monitoring Program. This provided the opportunity to maximize resources and boost the sample size from 29 to 49 randomly selected lakes.

Four additional lakes, or “targeted lakes,” were identified for sampling based on suggestions from DEQ Water Quality staff and the Oregon Lakes Association . They are Lake Abert, Barney Reservoir, Hagg Lake and Woahink Lake. This brings the total of lakes and reservoirs evaluated to 53. The Survey lists the results for the targeted lakes in Appendix A.

“Oregon’s lakes are special places, and this assessment provides a great deal of solid information about their environmental health,” said DEQ's Laboratory Administrator Lori Pillsbury. “The results will inform how we continue to protect our lakes, and make improvements where needed.”

There were areas of concern in some Oregon lakes and reservoirs. Excess nutrients were observed as the most widespread indicator of poor conditions. For example, while 74% of Oregon lakes were estimated to be in good condition with regard to phosphorous levels, 21%, or approximately 1,000 lakes, were estimated to be in poor condition. Additionally, about 60% of the state’s lakes were estimated to be in good condition with regard to nitrogen, while about 13%, or approximately 600 lakes, were estimated to be in poor condition. Excess nutrients frequently come via run-off from homes, developed areas and agriculture, as well as from soil erosion and decaying organic material. In addition, nitrogen may be added from burned fossil fuels in the atmosphere.

The Survey of Oregon Lakes covers six indicators. The first five align with NLA sampling: trophic state, biological, chemical, physical and contact recreation. These categories allow direct comparisons to the results observed at national and regional scales. The sixth indicator is toxics, which is being reported for the first time in Oregon due to the additional toxics monitoring funding.

The NLA is a collaboration between the EPA and state, tribal and local partners to monitor and assess the status and trends of ecological conditions in the nation’s lakes and reservoirs. Samples are currently being collected for Oregon’s contribution to the NLA through DEQ’s Biomonitoring Program. You can find the 2017 Survey of Oregon Lakes at

About the Oregon Department of Environmental Quality

The [Oregon Department of Environmental Quality]( protects human health and the environment by controlling air and water pollution, reducing the impacts of manufactured products and cleaning up contaminated properties. DEQ engages the public in decision-making and helps communities solve problems in ways that are economically and environmentally sustainable.

Media Contact:

Susan C. Mills, public affairs specialist,, 503-956-9648

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