The existing sewage collection system in the City of Grants Pass is comprised of 23 separate drainage basins and a total of about 0.8 million feet of sewer pipelines ranging in size from 4 inches to 42 inches in diameter. Approximately one-half of these sewers are at least 50 years old, with most of the old pipes clustered in the downtown area.
From the late 1920s through the mid-1960s, most sewers were made locally. These concrete and terra cotta pipelines were constructed from substandard materials and have poor long-term performance. Among the oldest and poorest of these pipelines is the Pine Street Sanitary Sewer located in the downtown area along Pine and 2nd streets from Rogue River Avenue to “A” Street which is close to City Hall.
The Pine Street Sewer project consisted of open trench placement of 4,270 feet of new 18-inch diameter PVC sanitary sewer pipe and service laterals, 1,900 feet of new 21-inch diameter PVC sanitary sewer pipe and service laterals in a residential portion of Grants Pass, Ore.
The scope of work also included reconstruction of the streets where the sewers are installed, including an entirely new street asphalt surface from curb to curb within the project area and a new properly compacted road subbase. The project also included one 100-foot long guided auger bore beneath the Central Oregon and Pacific Railroad right-of-way crossing, and new twin 12-inch diameter sewer pipes within an existing culvert which contained a steelhead spawning stream.
Additionally, the project included installation of 2,250 feet of 12-inch diameter perforated storm drainage pipe for groundwater collection and discharge, installation of 19 new
commercial driveway approaches in each of the alleys within the project area, 2,084 feet of new curb and gutter, 10 new wheelchair ramps, and 835 feet of new sidewalk.
Initial project estimates suggested that two dry weather seasonal construction periods might be required in order to complete construction of the new Pine Street Sewer. This was due to limited periods of low groundwater in the project area that would enable the new sewer pipe to be installed without significant dewatering in the pipe trench. The project was
ultimately completed in a single construction season with very little, if any, construction trench dewatering. This was possible through creative staging and utilization of multiple crews in different areas.
James W. Fowler Co., in partnership with the City of Grants Pass and Parametrix, Inc., was awarded the 2008 Project of the Year for the Pine Street Sanitary Sewer from the Oregon Chapter of the American Public Works Association. This award recognizes excellence, innovation and cooperation with regard to the management and administration of public works projects through the alliance of the managing agency, consultant and contractor.