West Biddle Dam Replacement

Location: Vancouver, Washington

Cost: $1,695,651

Completion: October 2023

Owner/Developer: Columbia Springs

Architect: Not applicable

Engineer: Windsor Engineers

General Contractor: Tapani

Submitting Company: Tapani

Subcontractors: Bar M Steel Commercial, Karvonen Sand & Gravel, North 40 Fencing

West Biddle Lake Dam, nestled within the Vancouver Trout Hatchery, was built by Spencer Biddle in 1925 for fish rearing purposes. Management of the dam eventually transferred to the Washington Department of Fish and Wildlife.

Tapani recognized the delicate balance between preserving history and embracing modern engineering on the project. Work began with collaboration between Tapani and WDFW to remove fish from the lake, which they accomplished in a single day. The construction team then demolished the old dam within a week’s time and erected a new 98-foot dam, designing it to mirror the original structure while incorporating modern features such as a spillway and crossing.

The removal of a historic dam and its replacement, conducted within a 100-acre nature park, was a feat of engineering and environmental stewardship. The initiative not only facilitated the crucial dredging of 400 cubic yards to augment downstream habitat and sediment capacity, but also required the replacement of the existing raceway waterline. These efforts demonstrated a commitment to both preserving natural ecosystems and meeting operational needs.

Tapani’s in-house virtual design and construction department crafted precise earthwork models of the site, laying the groundwork for efficient material management and project savings. Tapani self-performed a majority of the work on the project, helping to keep work on schedule and within budget. The contractor’s civil team excavated and relocated approximately 2,100 cubic yards of material from the site, including dredging 385 cubic yards of material from the downstream pond. Optimal soil moisture conditions simplified the process, removing the need for importing or exporting material. The company’s structural concrete team self-performed construction of the dam, and upon its completion added a new 50-foot prefabricated pedestrian bridge using salvaged materials from the historical site.

Additional scopes of work included installing a flow control device with stop logs, in-house fabrication of the trash rack, walkway supports and an overflow flume. These items, although small, added up in cost and time savings on the overall project. Major environmental considerations on the project included fish salvaging from both the dam lake and the pond, which was accomplished utilizing turbidity curtains and working closely with the Department of Environmental Quality.

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