Thursday, November 3, 2011

Largest Dam Removal in US

Diversion Channel Completed

The log boom just upstream of the Elwha Dam, seen in the photo above, will be removed on Friday, October 21. During the life of the dam, the log boom kept logs from hitting or damaging the dam. No longer needed, it will be removed, allowing the river's woody debris to float naturally downstream where it will enhance habitat for fish and other wildlife.

Today, the Elwha River flows through a new diversion channel, allowing contractors to access and remove the 'stairstep' gravity dam on the left side of the photo.

The new diversion channel at the Elwha Dam is finished, and yesterday morning, crews opened the coffer dam above it. The photo at right shows the river flowing through the new channel. Thanks to videographer and Olympic NP volunteer, John Gussman, for sharing this time-lapse series of film clips. In the space of less than 90 seconds, John shows us the 3-hour transition from the old channel to the new. (Side note: John filmed these clips from the Elwha Dam Overlook trail, a ten-minute walk from the trailhead parking lot on Lower Dam Road.)

Effective immediately, the exposed reservoir areas of Lake Aldwell and the remaining Lake Aldwell are closed to public use.

This emergency closure is designed to protect the public from hazardous conditions caused by the draining of Lake Aldwell and removal of the Elwha Dam and associated structures. The log boom that prevents boats from drifting over the dam will be removed at 2:00 p.m. tomorrow, October 21. Without the log boom, there is no barrier between the remaining reservoir and the swiftly moving river as it flows over and down the new diversion channel. These factors make the area around the dam extremely unsafe for boating and other forms of recreation.

Once the log boom is removed, the raft of large logs behind it will move downstream with the river. Anglers and other downstream river users are urged to use caution around the river in the coming days and to be on the lookout for logs moving downstream.

Bookmark and Share


No comments: