The project involved exploration for a new fish passage facility at Albeni Falls Dam, which is located approximately 50 miles northeast of Spokane, WA on the Pend Oreille River. The facility will specifically be intended to help the currently threatened bull trout (Salvelinus confluentus) thrive in the Pend Oreille River system.
U.S. Army Corps of Engineers
Shannon & Wilson
Crux Subsurface, Inc.
Crux’s scope included eight geotechnical borings, two of which were in highly challenging locations. These borings were located on a rock outcrop on the intake side of the dam and required a 30-ton crane to mobilize drilling equipment. The remaining borings were accessed by low-pressure rubber track carrier. Borings ranged from vertical to 20 degrees from vertical, and were drilled to between 68 and 109 feet. Packer testing was completed on 10-foot intervals in all borings, downhole imaging was performed in all borings, and vibrating wire piezometers were installed in six of the eight borings.
A confined operational area at one of the track borings added to access challenges on the project. The positioning of the dam out-building and angled fence line created such tight conditions that crews needed to walk around the perimeter of the building to move from one side of the drill to the other. Unexpected repair work on a spillway gate also created setup challenges at crane sites, as it required a change in where the crane could be positioned. Crux worked closely with the crane company to ensure the new position would not create any issues. Additional project challenges included significant snow accumulation during the first week of the project, creating slippery conditions. The snow created subsequent issues locating underground utilities, as the markings continuously melted with the snow and needed to be redone.
All work was completed safely and within the budgeted project schedule, demonstrating Crux’s ability to remain flexible and on-task in the face of challenges.