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Eugene -Springfield Area Natural Hazards Mitigation Plan <br />6. Appendices <br />EWEB dams meet current standards and in compliance with state and federal <br />regulations.10 Regulators works with EWEB to perform annual inspections to ensure <br />safe operating conditions. Each EWEB dam receives weekly, monthly, semi-annual, <br />and annual inspections. Every five years, the Federal Energy Regulatory Commission <br />requires EWEB to test emergency action plans for the dams. <br />As Table H-3 shows, seismic considerations were completely absent in the design of <br />Dorena and Fern Ridge dams. The others were explicitly designed to ground shaking <br />levels of 0.10 g, which is the maximum seismic design level for any of the Corps dams <br />in western Oregon. In contrast, the current Corps seismic design levels for dams at <br />these sites (i.e., if new dams were to be built today) would be 0.21 g to 0.24g for the <br />dams in eastern Lane County and 0.35 g for Fern Ridge. Current seismic design <br />requirements are for levels of ground shaking about two times higher than the probable <br />design levels for most of these dams and about three times higher for Fern Ridge. To <br />ensure that the probability of dam failures in Lane County remains low, the Army <br />Corps of Engineers conducts regular seismic evaluations of each dams to ensure that all <br />dams meet current safety requirements. 11 <br />Table H-3 Seismic Design, Evaluation and Inspection Data <br />Dam <br />Date of <br />Last <br />Seismic <br />Evaluation <br />Seismic Design Basis <br />Date of Last <br />Periodic <br />Inspection <br />Original <br />Current <br />Cottage Grove <br />1981 <br />None <br />0.21 g <br />1997 <br />Dexter <br />1981 <br />0.10 g <br />0.21 g <br />1996 <br />Fall Creek <br />1981 <br />0.10 g <br />0.21 g <br />1999 <br />Dorena <br />1981 <br />none <br />0.21 g <br />1997 <br />Lookout Point <br />1981 <br />0.10 g <br />0.21 g <br />1999 <br />Blue River <br />1994 <br />0.10 g <br />0.24 g <br />1996 <br />Hills Creek <br />2000 <br />0.10 g <br />0.22 g <br />1999 <br />Cougar <br />1994 <br />0.10 g <br />0.24 g <br />1997 <br />Fern Ridge <br />2001 <br />none <br />0.35 g <br />2000 <br />Source: Army Corps of Engineers, Portland District, March 2001. <br />11 Oregon. EWEB, `Dam Safety', Dam Safety is a Top priority, Eugene, OR, 2017, <br />http://www.eweb.org/about-us/news/dam-safetv-is-a-top-priority, Accessed August2019. <br />11 United States. Army Corps of Engineers, Portland District Office. Seismic Design, Evaluation and <br />Inspection Data for Corps of Engineers Dams. March 2001. <br />6-135 January 2020 <br />