John Day Dam Flow Deflectors - Rufus, Ore.
The work included 8,000 cu yd of concrete and all work was coordinated with the operations of a fully functional flood control and power-generating dam. The 17 pier nose extensions were constructed prior to the deflectors using specially designed forms, each weighing 57-tons. The bulkhead forms, weighing 125-tons each, were designed and built to act as concrete contact surfaces and as cofferdams to maintain a dewatered work area for the demolition of the ogee face and construction of the new deflectors. Demolition required the removal of reinforced concrete using concrete cutting saws, and rock drilling and splitting tools. All water from cofferdams was collected and pH tested prior to returning it to the river. Despite unusually adverse river flows, the work was completed one year ahead of schedule.