India Street Wastewater Force Main Condition Assessment

A physical condition assessment of the India Street Wastewater Force Main is scheduled for early August, 2025 using a technologically advanced, free-swimming inspection tool. The inspection will assess 1.3 miles of 33-inch prestressed concrete cylinder pipe (PCCP) manufactured in 1976. This pipe runs from the India Street Pump Station to the discharge manhole at the East End Wastewater Treatment Facility, primarily along Commercial Street and the Eastern Trail adjacent to Casco Bay.

Assessment Method and Partners

Condition assessment of a pressurized pipeline requires advanced tools developed by qualified vendors. Portland Water District (PWD) has partnered with INSIGHT Water Technologies and HDR to complete this inspection.

PWD will deploy INSIGHT’s XK1 platform, a neutrally buoyant device approximately 9 feet long with fins 33 inch in diameter (see Figure 1 for a 3D rendering). The tool performs detailed internal scans while the pipe remains in service. It detects broken wire wraps, the leading cause of catastrophic PCCP failure, by analyzing the collected data.

In addition to broken wire wrap detection, the tool also:

  • Utilizes onboard acoustic sensors to report the location of leaks and pockets of trapped gas
  • Employs an affixed rotating sonar profiler to quantify the level of debris and measure the size of gas pockets

Tool Insertion and Pipeline Access

The tool will be inserted via a bypass connection located on the eastern side of the India Street Pump Station, between the pump station and the Fish & Bone pet supply store. An insertion stack will be mounted to the bypass valve flange, and the tool will be loaded into the stack.

With the stack cap sealed and the bypass valve opened, the tool will be pushed into the live force main and travel with the flow inside the pipe.

Tracking and Trail Impacts

To track the tool’s location during the inspection, three tracking sensors will be installed along the pipeline (see Figure 2 for an inspection overview map).

  • Vehicle traffic: No impact expected
  • Pedestrian traffic: Portions of the Eastern Trail may be temporarily rerouted near the work zones

Tool Extraction

The tool will be extracted from the force main discharge manhole structure where it will be captured by a pre-installed extraction rack. This is located at the end of the Eastern Promenade Midslope Trail.

Timeline and Preparations

This project will take place between July and August and includes:

  • Site preparation at the bypass connection – slight construction noise is expected during this time
  • Installation of tracking sensors
  • A dry run of the inspection

On the inspection day:

  • Access between the pump station and Fish & Bone will be restricted (see Figure 3 for access details)
  • Slight construction noise is expected during this time
  • The launch process will take approximately three hours

Why This Matters

The force main is a vital component of PWD’s wastewater infrastructure, conveying both wastewater and stormwater from the India Street Pump Station to the East End Wastewater Treatment Facility. While the pipe has never failed, there is no backup line. A failure would require emergency repairs and could result in service disruptions and/or environmental impacts.

This inspection will help PWD:

  • Understand the pipe’s current structural condition
  • Proactively plan for repairs or replacement
  • Prevent costly and disruptive emergency failures

Questions?

Please contact the PWD Project Manager, Helen Newman, at (207) 523-5279 or hnewman@pwd.org