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Review and Synthesis of Available Information to Estimate Human Impacts to Dissolved Oxygen in Hood Canal
Citation:
Review and Synthesis of Available Information to Estimate Human Impacts to Dissolved Oxygen in Hood Canal. U.S. Environmental Protection Agency, Washington, D.C.
Impact/Purpose:
This report is in response from a request for a science summary from the Hood Canal Coordinating Council (HCCC), a consortium of local governments and stakeholders in the Hood Canal watershed.
Description:
This is a draft review and synthesis of monitoring and analysis conducted by several departments at the University of Washington, U.S. Geological Survey, Pacific Northwest National Laboratory, Kitsap County, and Mason County. The report summarizes findings from a 2008 peer-reviewed study of sediment cores from Hood Canal. This study found that dissolved oxygen conditions in Hood Canal were better in the 20th century than in the 19th century despite the increase in human activity over that period. The sediment cores also indicated that oxygen conditions have varied in a long-term pattern similar to decadal climate oscillations. Consistent with this finding, available analysis indicate that human releases of nitrogen are not significantly contributing to the low dissolved oxygen levels in the main arm Hood Canal, where the influx of oceanic nitrogen greatly exceeds the nitrogen inputs from surrounding watersheds. The report summarizes a compelling finding by the Hood Canal Dissolved Oxygen Program (HCDOP) that periodic fish kills are caused by a cascade of natural processes that include the influx of nitrogen-rich ocean water, low river flows in late summer, and strong southwesterly winds. A consistent finding in the available information is that the greatest human impacts to dissolved oxygen likely occur at the landward terminus of Hood Canal (Lynch Cove). We find that the current impact from human-caused nitrogen releases may be cause for concern, but the available information in this area is uncertain.
URLs/Downloads:
Review and Synthesis of Available Information to Estimate Human Impacts to Dissolved Oxygen in Hood Canal (PDF, NA pp, 3990 KB, about PDF)Peer Review Plan (PDF, NA pp, 33 KB, about PDF)
EPA and Ecology Response to Peer Review Comments (PDF, NA pp, 140 KB, about PDF)
Peer Review Comments and Responses (PDF, NA pp, 46 KB, about PDF)
Independent review-Comments -Hood canal Appendix A (PDF, NA pp, 55 KB, about PDF)
Independent Review Panel Report 5-23-12 (PDF, NA pp, 709 KB, about PDF)
Peer Review Panel (PDF, NA pp, 44 KB, about PDF)