Environmental Services has completed the latest phase of construction on a project to repair the deep and wide Southeast Interceptor sewer tunnel. Built in 1954, the sewer tunnel runs parallel to the Willamette River under inner southeast neighborhoods and is between 5 to 6 feet wide and 25 to 54 feet below the surface. The repairs will extend the life of the sewer and protect public health, water quality and the environment.
Two segments of the Southeast Interceptor require repairs (see map below).
The south segment starts at SE 16th Avenue and SE Pershing Street in the Brooklyn neighborhood. The line follows SE 16th Avenue north to SE Powell Boulevard, continues north along SE 14th Avenue to SE Gideon Street, and travels northwest on SE Gideon Street to SE 11th Avenue. After a short distance on SE 11th Avenue, the line follows the railroad tracks to a point just west of the intersection of SE Division Place and SE Division Street. From there, it follows SE Division Street to the northwest. The south segment ends at SE Division Street and SE Grand Avenue.
The north segment starts at the intersection of SE Grand Avenue and SE Stark Street, follows SE Grand Avenue north to NE Davis Street, and then extends from NE Davis Street west to NE 3rd Avenue.
Work zones will be located at manholes and will move as project segments are completed. Work at each manhole may last up to two months. Crews will begin in the southernmost segment and move northward as they finish work at each manhole.
The project is anticipated to be completed by the end of October 2018.
The project has several phases of construction activities:
- set up temporary sewer bypass system
- remove sediment from the Interceptor sewer tunnel
- clean the sewer tunnel
- prepare pipes and drill holes for grouting work
- complete grouting work to repair the tunnel
- patch grouting holes
- remove temporary sewer bypass system
There may be periods of inactivity due to a variety of factors, especially weather. Crews can safely work in the Southeast Interceptor tunnel only on dry days when there will be no flow in the tunnel from rain or other parts of the sewer system. Project managers monitor the weather forecast closely and adjust operations at each work site accordingly.
The city will do daytime work in the southern project work zones. For traffic safety and to minimize traffic congestion, the city will do night work in the northern project work zones. See map for details.
Work in the southern segment will occur during the day from 7 a.m. to 6 p.m. Monday through Saturday, except the work between SE 11th and SE 12th Avenues, where the Portland Noise Office approved work from 6 p.m. to 7 a.m.
Night work will occur in the northern segment of the project (NE Davis to SE Stark) from 8 p.m. to 6 a.m. Monday through Saturday. Call the noise hotline at 503-823-8353 to report concerns about nighttime construction noise.
Portland noise code allows construction from 7 a.m. to 6 p.m. Monday through Saturday. Work after 6 p.m. and before 7 a.m. and all hours on Sundays requires a noise variance from the Portland Noise Office. Because construction crews will work past 6 p.m. and on weekends at some locations in this project, Environmental Services applied for and was granted a Noise Variance.
A generator will be running all hours, all days (24/7) in all segments of the project to pump sewage and stormwater from the sewer line so that crews can safely work inside the sewer pipe. The city's contractor is taking measures to reduce noise from the generator and the vactor truck used to clean the pipes so that nearby properties will not be disturbed.
The city's contractor will repair approximately 7,400 feet of the deep and large-diameter Southeast Interceptor sewer tunnel. Crews will access the sewer from manholes along the Interceptor as illustrated on the project map. Crews will drill small holes through the sewer tunnel walls and then pump cement grout through the holes to fill voids outside the tunnel that have developed over time. This will also stop infiltration leaks that have allowed groundwater to seep into the sewer tunnel.
Using equipment that will be contained on a 40-foot semi-tractor trailer, crews will mix the cement grout and then pump it through hoses running down into the sewer tunnel and through the small holes they drilled into the tunnel walls. This process will require ventilation of the sewer system to provide air supply to crews working inside the tunnel.
There will be some around-the-clock, 24/7 pumping of sewage and stormwater. This work will be almost entirely contained within the sewer system below the street surface.
Noise reduction equipment will be used to reduce the noise of the standard generator mounted on a small trailer in the work zone. The generator will sound similar to the noise of standard traffic, a normal conversation, or a power tooth brush. Note that the noise comparisons mentioned above are based on noise measurements taken next to the generator. Noise dissipates quickly with distance, so most adjacent properties should not be disturbed by the generator noise.
Additional noise mitigation measures will further reduce noise from the generator and the vactor truck used to clean the pipes.
What to Expect During Construction
You can expect the following activities and impacts with this sewer repair project:
- The sewer repair method for this project can be completed from inside the sewer tunnel and will not likely require digging trenches in the roadway.
- Equipment that generates noise will include vactor trucks, compressors, generators, ventilation fans, and other trucks and related equipment. Night work in the northern segment of the project will also require lighting of the project area.
- Vactor trucks will be in the area to operate vacuum pumps necessary to clean the pipe tunnel and remove material during construction. Vactor trucks generate noise and may be in place for several hours at a time.
- There may be periods of inactivity between construction phases due to a variety of factors including weather, subcontractor schedules, and availability of materials.
- A city inspector will be on-site during work hours and may be able to assist you with an immediate need during construction.
- Sewer, water, and other utilities will remain in service during construction.
You can expect the following traffic controls and impacts during construction:
- Accessing the sewer line through manholes will require temporary lane closures, which will require traffic control and construction signage. Where needed, traffic will be routed around the worksites.
- Traffic controls (cones, flaggers, temporary barriers, etc.) will be in place only during work periods and removed daily where possible.
- Local access to all properties will be maintained, but construction may create delays.
- On-street parking will be temporarily removed in and near the work zones to create a safe work environment and to stage equipment and materials.