The scope of this contractor was isolated to the Lower Monumental Dam’s Navigational Lock Tainter Valve No. 4. Excessive vibration during operation justified the replacement of the tainter gates trunnion pin assembly. Bulkheads were installed to isolate the Valve from the water while crews worked in the 130 foot shaft to temporarily support Tainter Valve No. 4. Existing trunnion pins were pulled along with removal of the existing bronze bushings. Field line boring was performed to assure proper alignment and installation of the new bronze bushings. Valve No. 4 was then lowered back into location and new trunnion pins were installed to complete the project on time in May of 2016.