Glen/Mar performed major modifications to Spillbay 20 at John Day Lock & Dam, including dewatering the spillbay approximately 55 feet, diving operations, concrete demolition, structural anchoring and fabrication and installation of a new flow deflector.
The work included approximately 1,500 cubic yards of new ogee concrete, barge-crane and floating-plant operations, removal and replacement of dam components, and relocation and installation of a 45-ton Top Spillway Weir. Construction was coordinated around ongoing dam operations and the requirements of multiple agencies and stakeholders working within the Columbia River system.
