Select Projects

Ballard Siphon Replacement Rebid

This project included construction of launch and retrieval shafts and 2,100 feet of 114-inch segmentally lined tunnel with an 85.5-inch diameter final liner. Additionally, two existing 36-inch wood stave pipelines were slip-lined with steel liners. Common when the siphon was originally constructed, the original pipes were similar to wooden barrels with metal compression bands holding the … Continue reading Ballard Siphon Replacement Rebid

Bonneville Bradford Island Branch B Fish Ladder Repair

This emergency project for the historic Bonneville Branch B Fish Ladder on Bradford Island at the Bonneville Dam on the Columbia River was necessary to repair a scoured fish ladder structure and replace the failed riprap revetment. This work involved a very strict in-water work window to complete the fish ladder and allow the US … Continue reading Bonneville Bradford Island Branch B Fish Ladder Repair

Balch Consolidation Conduit Shafts & Pipelines

The Balch Consolidation Conduit Shafts and Pipelines project (“Balch”) was a key component of the City’s Controlled Sewer Ooverflow program and required installation of 8,000 feet of 84-inch and 54-inch diameter pipes via microtunneling at depths of 20 to 75 feet to carry sewage and stormwater runoff from the Balch Drainage Basin to the West … Continue reading Balch Consolidation Conduit Shafts & Pipelines