Blue Lake Expansion Project (Marine/In-Water)
The entire Blue Lake Expansion Project focused on water, saving it up in a rainy climate and ultimately continuing to use it to create electricity for the island community. The water in Blue Lake also played a significant role in the dam raise project throughout the course of construction. Winter’s seasonal high water on the lake served as our assistant, providing our Team access to the spillway from a barge, where a crew during our first construction season scarified the existing ogee spillway in preparation for Season 2 concrete placement. The dam was raised by 83 feet to its maximum geotechnical height. The barge we used to support the roadheader for this work also supported the 100-ton crawler crane needed to remove, repair and replace a damaged gate on the soon-to-be-decommissioned intake. The barge also proved critical to dredging operations when we set up the clamshell to clear years’ of detritus discovered clogging the area around the Howell-Bunger valve during diving operations early in the project.
Access to the dam from the barge remained an advantage to the work for the three months that the lake remained high. We were extremely mindful of the importance of all aspects of this pristine water as we planned, scheduled and conducted our work. Blue Lake, also the water source for Sitka, contains some of the cleanest water in the U.S.
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