Removal of the Elwha Dam

View of the Elwha dam from downstream
A view of the Elwha dam from downstream, holding back Lake Aldwell

Dam Removal Strategy:

  • The first step in removing the Elwha dam will be to lower the reservoir's water level by using the existing water intakes and spillways approximately 15 feet.
  • A temporary diversion channel will then be excavated through the left spillway to allow Lake Aldwell to be further drained.
  • Coffer dams -- temporary structures acting as dams -- will then be installed to direct reservoir outflow into the temporary diversion channel.
  • This will allow the remaining water immediately behind the concrete dam to be pumped out and the fill material behind the dam to be removed under dry conditions.
  • The concrete dam can then be removed and the original river channel restored.
  • The powerhouse and all other structures will be removed and the temporary diversion channel will be refilled.
  • Finally, the site will be re-contoured and revegetated to most closely resemble the pre-dam condition.

Link to 2006 article in Popular Mechanics: "Tearing Down the Elwha Dam"

 

 
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This webpage was made possible in part by a grant from Washington’s National Park Fund.
 
 

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