2nd RSW at Ice Harbor Dam Walla Walla Army Corps of Engineers | 2004-2005

The Ice Harbor Dam RSW is the first production Removable Spillway Weir to be installed on the Snake River. The 1100 ton fish bypass structure was installed in spillbay 1 on the upstream side of the dam. As with the prototype, the RSW is hinged on the dam face and rotates to an up or down position using ballast tanks and a computerized ballast system.

Underwater installation tasks included drilling 16′ x 3.5″ core holes for grout injected anchor bolts using the drill pictured, undercut anchor bolt installation for bearing pads, and side seals. Concrete demolition was also required and state of the art wire saw techniques were utilized to remove portions of the pier nose. The specialized underwater wire saw is shown below. Remove drills, sonar, and sub-sea cameras were used to install the various components required to install the weir.

AUS performed hundreds of dives in depths of up to 135 FSW to complete the project. The project was completed under severe time constraints, on time, and with no lost time accidents. The RSW is operational for the 2005 spring fish migration.

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