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Similkameen River FERC Preliminary Permit and Feasibility

Client: Okanogan PUD No. 1

Location: Similkameen River, WA

Summary: Cardno ENTRIX prepared a Preliminary Permit application to FERC for the Similkameen Project, located at Shanker?s Bend on the Similkameen River, near the Canadian border in Northcentral Washington. Subsequently, an appraisal level feasibility study was conducted of the project, in coordination with the State of Washington, Columbia River Water Management Program. The study addresses several options:

  • High Dam Option (1.7 MAF, elevation 1289?)
  • Medium Dam Option (168 TAF, elevation 1175?)
  • Low Dam Option (50 TAF, elevation 1155?)

The Project was found to provide regionally important water storage, hydroelectric power generation, and flood control benefits, as well as recreation and instream flow benefits offsetting effects to Native lands and peoples, wildlife, wetlands, and inundation of infrastructure and property.

Water storage benefits include up to 1.3 M acre-feet of usable water or flood control storage (under the High Dam option) and the capacity to generate as much as 74 MW (average annual generation 232,000 MWh) of clean, renewable power. The High Dam could irrigate 487,000 acres of alfalfa or supply domestic water to 3.3 M households. The energy it generates would be able to serve 15,000 households. The environmental benefits of the project include the ability to provide minimum instream flows of cool, clear water with higher concentrations of dissolved oxygen, improving survival of all salmonid life stages in the Similkameen and Okanogan rivers. The project could provide instream flows. It could provide Flow releases of 700 cfs through the summer to benefit 618 miles of the Similkameen, Okanogan and mainstem Columbia rivers, and would cool existing water temperatures in the Similkameen and upper Okanogan by as much as 2o C.The initial appraisal study assists State and local decision-makers in selecting options for more detailed feasibility study and possible licensing. Decision objectives include project location, scale, and conceptual design.