The work on this project consisted of two major features of work. These were armor plating the base of a concrete spillway, and installing a new gabion structure downstream of an existing concrete stilling basin. The work involved concrete removal; drilling and installing epoxy anchors for the armor plates; installation of new stainless steel armor plates; grouting the void behind the plates; and installation of joint sealant between the plates. Installation of the gabion structure required clearing and grubbing; excavation and finish grading; installation of gabion baskets; shotcreting over the gabion baskets; and installation of riprap downstream of the new gabion structure. This work all was completed in the Walla Walla River during a tight in-water work window. Constant dewatering activities were required to complete all phases of work.
Project Team and Stats:
Owner: US Army Corps of Engineers
Location: Milton-Freewater, OR
Start Date: July 2014
Completion Date: September 2014