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"