City of Port Angeles – Combined Sewer Overflows Reduction

Project overview

Vanir served as the project and construction manager for the City of Port Angeles’ two-phase Combined Sewer Outflows (CSO) Reduction project. Phase I of the project included installation of over 16,000 linear feet (LF) of high-density polyethylene force main and gravity sewer pipelines using innovative sliplining techniques and open-cut trenching along the Olympic Discovery Trail. The work involved improvements to the trail and bridges along the path, as well as the construction of a new 105-foot bridge over Ennis Creek. A vital part of this project was the rehabilitation of and modifications to an existing five-million-gallon steel storage tank.

The project’s second phase included the replacement of Pump Station 4 with a new 28-million-gallons-per-day pump station; construction of a new influent sewer to divert flow from the existing pump station to the new one; 2,600 LF of a new gravity diversion sewer; approximately 1,200 LF of new force mains; stormwater improvements; filtration, temporary storm and groundwater treatment; and installation of approximately 1,000 LF of new storm drains.

This project will have long-term benefits to the community with improved harbor water quality and greatly reduced CSO events.

A challenging project delivered on time and within budget

Much of the project was located on a contaminated site, which required all demolition and excavation to follow strict requirements for hazardous materials handling and storage. This involved comprehensive monitoring, testing, inspection and material handling management. The site also required extensive coordination, documentation and monitoring efforts as it was an extremely sensitive archaeological area for the Lower Elwha Tribe. Through Vanir’s proactive coordination efforts with the contractor, the project was completed on time and within budget, providing numerous cost savings to the City.

Port Angeles, Washington
City of Port Angeles

Brown and Caldwell


Phase I: IMCO General Construction

Phase II: TEK Construction

Square Footage
Phase II Pump Station: 8,032 SF
Construction Cost
Phase I: $16.8 Million; Phase II: $15 Million
Start Date
Completion Date