This project was a design-build contract for the City of Cottage Grove. The existing system was located at two sites that were more than twenty miles apart with a capacity of approximately two MGD. Our team converted the existing Row River site to a pall membrane system capable of uninterrupted deliveries of four MGD with future capacity of an additional two MGD. As part of the conversion, new chemical systems and tanks were constructed, two additional settling ponds, and a new eight MGD surface water intake structure components of the work include a 30’ x 30’ Z sheet cofferdam cell into the Row River.
This project also included the dewatering via submersible pumps to a retention basin with a filter dam and then piped 300’ to wetlands. Turbidity was monitored daily by the owner during installation and removal of the cofferdam and was always within permit. Fish rescue was performed numerous times throughout the process and closely coordinated with the ODFW. At the intake structure, fish screens were installed with a new compressed air and air burst system. Six 100 HP vertical turbine pumps were installed in the new concrete surface water intake structure and modifications to the existing facility included adding a membrane filtration system that had complex mechanical piping, valves, and sluice gates.
Total Project Value: $9.5 million
Slayden Construction Role: Design Build General Contractor
Owner: City of Cottage Grove