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Taggart Outfall Sewer Project

Sewer and Stormwater
Active
Environmental Services has resumed construction on a project to improve the function of the Taggart Outfall sewer tunnel. Last year crews repaired 3,700 feet of sewer pipe inside the tunnel. This year crews will modify an existing maintenance hole to improve its function during high rainfall events.
Photo shows old brick sewer pipe tall enough for a person to stand in with new fiberglass pipe liner being carried by small minature train.
Environmental Services is constructing an additional maintenance access hole improvement in late 2022 to early 2023.
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Environmental Services will modify an existing maintenance hole to improve its function during high rainfall events.

Crews will construct a diversion dam inside the maintenance hole in the intersection of SE 17th Avenue and SE Tibbetts Street. The diversion dam will help manage the sewage and stormwater that flow into the Taggart Outfall sewer tunnel. During high rainfall events, the dam will divert increased flows to another part of the public sewer system that can accommodate the flows.

This improvement will reduce the risk of too much flow within the sewer tunnel, thereby reducing the risks of street and basement flooding in Southeast Portland.

Project Area

The maintenance hole is located in the intersection of SE 17th Avenue and SE Tibbetts Street.

Taggart Outfall Sewer Repair Project Map

What’s Happening Now

Crews completed installation of a large maintenance hole in the intersection of SE 17th Avenue and SE Tibbetts Street. Crews replaced the existing concrete weir system inside the maintenance hole with a new fiberglass weir. The new weir will help to control the flow of combined sewage and stormwater through the maintenance hole channel. Fiberglass provides several benefits over concrete, including being more resilient than concrete. Concrete can easily be subject to cracks and erosion by gases in the sewage. 

The city's contractor is awaiting shipment of replacement gaskets to install between the stoplog rails and the concrete wall of the maintenance hole. Stoplog rails are engineered hydraulic controls that help control the flow of water through the maintenance hole channels. The new gaskets will help seal the stoplog rails and prevent leaks. 

What to Expect During Construction

You can expect the following activities and impacts:

  • Regular work hours will be during the day from 7 a.m. to 6 p.m. Monday through Friday, and Saturday as needed.
  • Traffic controls will be necessary to establish a safe work zone for crews and a safe traffic environment for the traveling public. Please obey all signs and share the road safely.
  • On-street parking will be removed in the work zone, and travel lanes may be narrowed or restricted. Sidewalks will remain open.
  • Local access will be provided to driveways, businesses, and residential properties, but you can expect periodic delays.
  • There may be weather delays because crews can only work inside the maintenance hole during dry weather. 
  • Sewer, water, and other utilities will remain in service during construction.

Noise Concerns

Construction of this maintenance hole work will be much quieter than construction of the pipe repairs inside the sewer tunnel last year. It will be necessary to ventilate the maintenance hole when crews are working inside it, but the fan will be smaller and quieter and will not operate overnight. In addition, there will be no pumps and generators operating during the day or night. 

Learn more details about what to expect during construction.

Extreme Weather

When high temperatures, extreme heat, near freezing temperatures, or extreme cold are in the weather forecast, crews may adjust schedules to protect workers from the dangers of heat stress and cold stress. When working in extreme weather environments, all City workers, contractors, and subcontractors must follow Oregon’s OSHA (Occupational Safety and Health Administration) mandates and Environmental Services’ Heat Illness Safety and Health Plan and its Cold Stress Safety and Health Plan. You may see crews taking more frequent water and rest breaks, stopping work at noon, and taking other protective measures during extreme weather.

We Want to Hear from You

Environmental Services will inform residents and businesses about project activities and respond to questions and concerns in a timely manner. We encourage you to:

  • Return to this project webpage for more information as the project evolves.
  • With questions or comments, please contact Cheryl Kuck by email or phone 503-823-7898.
  • If you have a question or concern, please be sure to include your name, property address, and project name (Taggart Outfall) in your voicemail and email so we can provide you more details about what to expect in front of your property.
  • If your basement sewer backs up or your property or street floods, please report it immediately to the City’s Maintenance Operations hotline at 503-823-1700. It is staffed 24/7, all hours and all days. 

Project Background

The Taggart Outfall is a critical public sewer line that serves Southeast Portland. It drains a large area of Southeast Portland and conveys overflows from the combined sewer system to the Willamette River during rain events. The large brick sewer tunnel is 115 years old and is located deep underground in a difficult location close to TriMet light rail tracks, Union Pacific Railroad tracks, and Highway 26/Powell Boulevard. A structural failure of the Outfall would have profound impacts on this area, potentially flooding numerous businesses and residences and resulting in many millions of dollars of property damage and disruption.

Between 2018 and 2021, this project designed and constructed repairs inside the Taggart Outfall sewer tunnel. Repairs will increase the sewer’s resiliency, extend its service life for up to another 100 years, and help prevent sewage releases.

Pre-Construction Activities 2018: The contractor for this project, James W. Fowler Co., conducted closed circuit television (CCTV) inspections and 3D laser profiling of the Outfall tunnel in the fall of 2018, which allowed the City to confirm existing conditions, create a profile of the sewer's interior, and then order the materials needed to repair the Outfall.

Mobilization in October 2019: During the fall of 2019, the city's contractor completed repairs to the small-diameter (58 to 84-inch diameter) pipe sections in SE 16th Avenue and in SE Tibbetts Street.

Re-mobilization in Spring of 2020: Crews mobilized again in March 2020 when weather permitted them to work safely inside the tunnel. This phase of work includes repairs to the large-diameter (118 to 120-inch diameter) pipe sections between SE 16th Avenue and the Willamette River.

Accomplishments in 2020: Crews completed the following work:

  • Construction of a deep sewer access shaft on private property at SE Powell Boulevard and SE 13th Place. The new shaft measures 15x15 feet wide and 35 feet deep. This shaft reduces the need for multiple access locations along the sewer tunnel.
  • Installation of 2,725 feet of steel tracks inside the Outfall sewer tunnel.
  • Installation of an electric, human-operated locomotive and pipe lining cart. Using a crane, crews lowered the locomotive into the sewer tunnel and onto the tracks. Similar locomotives have been used in mining and tunneling industries since the 1860s.
  • Installation of fiberglass-reinforced pipe lining. Using the locomotive, crews pushed the fiberglass-reinforced pipe lining along the track and into position inside the tunnel.
  • Installation of one section of pipe lining at a time. The project required 330 segments of 8-foot-long straight pipe, and 36 segments of joint pipe.
  • Pumping of grout into the space between the lining and the old brick sewer—done after every 100 feet of pipe lining installation.
  • Installation of new steel liner plates into the sewer tunnel, and assembly of the steel liner plates in place inside the tunnel.
  • Pumping of grout into the space between the liner plates and the old brick sewer.
  • Cleaning, inspection, and repair of a maintenance access hole. Casting a new concrete liner inside the existing maintenance access hole avoided digging in the street. The new concrete liner will create a watertight, corrosion-resistant interior that will reinforce the existing structure without having to replace it.

Accomplishments in 2021: Crews completed the following work:

  • Installation of a temporary groundwater test well.
  • Field testing to determine groundwater levels to determine remaining sewer tunnel repairs. 
  • Pumping of grout to fill and abandon the temporary groundwater test well.
  • Pumping of grout to seal the joints between the liner plates inside the sewer tunnel and strengthen the liner plates.
  • Abandonment of a buried maintenance access hole that is no longer needed for sewer tunnel access.
  • Closed-circuit television video inspection to verify successful completion of the sewer tunnel repairs.

Construction Methods to Repair the Sewer Tunnel

Environmental Services repaired approximately 3,700 feet of the Taggart Outfall sewer tunnel, which measures from 58 to 120 inches in diameter and from 20 to 75 feet deep.

The Taggart Outfall project was not a typical sewer construction project. There was very little aboveground construction activity and no digging in streets. Crews conducted repair work from inside the sewer tunnel deep underground.

The primary construction methods to repair the Taggart Outfall were Slip Lining and Tunnel Liner Plate. Crews entered the sewer tunnel from maintenance access holes and a sewer access shaft and climbed down 30 to 75 feet below the surface. Working from a locomotive on a steel track laid inside the tunnel, crews essentially constructed a new sewer inside the old brick sewer.

They constructed some sections by inserting a fiberglass-reinforced pipe liner inside the tunnel. They constructed other sections by assembling new steel liner plates in place inside the tunnel. They then filled the space between the new sewer and the old brick sewer with grout. These methods avoided digging trenches in the roadway and reduced aboveground impacts to the traveling public and adjacent properties.

For safety, crews could only work inside the tunnel on dry days when there was no water flowing into the tunnel. In the event of rainfall or a sudden surge of stormwater flowing into the tunnel, crews and equipment had to be removed quickly from the sewer tunnel, and completion of repairs were delayed.

Tunnel fans were necessary to provide ventilation to crews working in the confined space of the sewer tunnel deep underground. The fans had to operate all hours and all days when crews were inside the tunnel.

Public Impacts of Sewer Construction

While there was some equipment and materials aboveground, most of the work was conducted belowground inside the sewer tunnel. Environmental Services notified the surrounding neighborhoods that they could expect the following activities and impacts:

  • Temporary lane closures and on-street parking removal may be necessary to enable safe access to the sewer tunnel.
  • Equipment that generates noise will include vactor trucks, compressors, generators, pumps, ventilation fans, forklifts, and pile-driving equipment. 
  • Vactor trucks will operate vacuum pumps necessary to clean the tunnel and remove materials during construction. They may operate hours at a time.
  • There may be periods of inactivity between construction phases due to weather, subcontractor schedules, materials delivery, and other factors.
  • 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.

Work Hours during Sewer Construction

The Portland Noise Office granted Environmental Services a noise variance to work all hours and all days (24/7) in the industrial areas of the project west of TriMet light rail tracks to enable project completion during the dry-weather season. The noisiest work, such as well excavation, was done during the day from 7 a.m. to 6 p.m.

Noise Mitigation Measures

The major sources of noise were vactor trucks, grout pumps, water pumps, generators, forklifts, and tunnel fans. The contractor was required, by contract, to use quiet generators. Mitigation measures were incorporated into the construction contract. These mitigation measures were the following:

  • Night and weekend work is restricted to industrial areas where there are no residences within 200 feet.
  • All compressors and generators will be silenced.  Noise levels for quiet generators are around 69 decibels. 
  • Backup alarms on all trucks will be turned off and spotters will be used instead.
  • Vactor truck use and any required saw-cutting will not be allowed from 10 p.m. to 7 a.m.
  • Tunnel fans will be enclosed with sound barriers.
  • Lighting will be adjusted to the lowest levels to limit overshooting the work site and impacts to the immediate community.
  • City inspectors will be on site during work hours to enforce contract restrictions on noise.

Sign Up for Updates

Sign up for periodic email or text message updates for the Taggart Outfall Sewer Repair Project through our free GovDelivery subscription service. These updates are the best way to stay informed about what’s happening and what to expect. You can also sign up for bulletins on other projects and topics. 


This project will help protect the health of the Willamette River Watershed. 


Contact

Cheryl Kuck

Community Outreach
phone number503-823-7898Monday through Thursday, 7 a.m. to 5:30 p.m.
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