CSO Phase 2
Strider was contracted to do everything external to the pump station which consisted of all utility improvements within the downtown area of Port Angeles, and restoration of disturbed areas.
The Gravity Sewer components included installation of 14 Manholes up to 25’ deep and 120” diameter. Two of the largest were Epoxy coated along with the last leg of 42” concrete pipe. Sewer runs were installed in downtown city streets with summer tourist traffic, about 2,000 LF of which was down the middle of State Route 101 under WSDOT jurisdiction. Due to the potential impact on traffic, most of the installation was done at night. The 7,000 LF ranged in size from 18” to 42” and half of the overall trench required systematic dewatering with well points. At the confluence of the new sewer, a large CSO Vault was installed with a slide gate for directing flows during surge events.
In conjunction with the Gravity Sewer, three (3) Force Main sewers were installed and connected to the previously installed Phase 1 work. They were HDPE consisting of two 14” lines and one 30” line in a common trench of approximately 900 LF also down Front Street.
The Storm portion included a Treatment System with three 60” manholes and an Outfall structure terminating in the Bay. This was fed by a new collection system throughout common streets with the new sewer consisting of 1,500 LF of 8” to 18” pipe and a series of catch basins and manholes.
Strider was responsible for the multi-stage excavation of the 60’ x 90’ sheet pile cell (36’ deep) for the pump station. The excavation was fully shored and braced and required a substantial dewatering effort.
The restoration phase was elaborate consisting of new brick crosswalks, new curb bump outs with ADA access ramps, new striping and bike signage.