Oak Grove Hydroelectric Project

The Oak Grove Hydroelectric Project is a 44 megawatt hydroelectric plant operated by Portland General Electric (PGE) on the Oak Grove Fork Clackamas River. Water for this project is held by three lakes, built between 1923 and 1956. [http://www.portlandgeneral.com/about_pge/corporate_info/power_plants.aspx PGE power plant capacity] The dam creates the impoundment Lake Harriet.

History

In 1907, the Southern Pacific Company began to acquire water rights for the Oak Grove fork. [http://www.fws.gov/pacific/Fisheries/Hatcheryreview/documents/EagleCreekNFHReview_AppendixB_27July2007_FINAL.pdf FWS: Eagle Creek: Appendix B: history] These rights were transferred in 1911 to the Portland Railway, Light and Power Company, which later became PGE.

In 1923, the concrete diversion dam at Lake Harriet was completed. This lake holds {{convert|300|acre.ft}} [http://www.ferc.gov/industries/hydropower/enviro/eis/2006/12-21-06.asp FERC EIS P-2195] with a surface area of {{convert|150|acre|km2}}. [http://www.portlandgeneral.com/community_and_env/hydropower_and_fish/phototour/clackamas/harriet_dam.asp Photo tour: Harriet Dam] A {{convert|9|ft|m|adj=on}} pipeline goes downstream from Lake Harriet to the powerhouse. Power generation from the Oak Grove fork began in August 1924.Electrifying Eden: Craig Wollner, p 111

In 1953, Frog Lake was completed, adding {{convert|430|acre.ft}} of storage with {{convert|13|acre|m2}} of surface, which was later reduced to {{convert|266|acre.ft}} on {{convert|6|acre|m2}} in 1997. Finally, in 1956, the compacted-earth dam for Timothy Lake was completed, creating the largest lake in the system at {{convert|1430|acre|km2}} and {{convert|69000|acre.ft}}. The Oak Grove Powerhouse contains two Francis turbines.

References

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