Shelton - Seattle engineering and consulting firm Tetra Tech Inc. was recently recognized by the Society of American Military Engineers Seattle Post for its design of the Goldsborough Creek Dam Removal and Stream Restoration Project near Shelton, Wash. The firm received the society's Seventh Annual Design Excellence Award.

Located on land owned by Simpson Timber Company, Goldsborough Dam was originally constructed in 1921 to serve as a log holding pond and to provide hydroelectric power and water supply to the immediate area. It was abandoned in the 1950s but remained in place, preventing free upstream and downstream passage of resident and migratory fish and requiring constant maintenance. Removal of the 35-ft.-high, deteriorated dam structure had been considered for many years. However, because of the complexity and the cost of such a project, it was not pursued by Simpson or local agencies.

Tetra Tech became involved on the project in 1999, when the firm was hired as a consultant to provide engineering services that included advanced hydraulic, geotechnical, and design studies; preparation of plans, specifications, cost estimates, design reports, and an electronic bid package; and engineering support during the construction phase.

To restore fish passage to the 24-river-miles of high-quality fish habitat upstream of the dam, and to restore and stabilize Goldsborough Creek in the vicinity of the dam site, Tetra Tech used a design that included 36 individual weirs that were constructed using steel H-piles and precast concrete panels, with cast-in-place concrete weir caps. It also included rock and bio-engineered bank protection to prevent erosion and flanking of the weirs during large flood events.