How GPRS Uncovered a Collapsed Sewer Pipe in Pittsburgh

Video Pipe Inspection Services Helping to Map City’s Aged Wastewater Infrastructure

How GPRS Uncovered a Collapsed Sewer Pipe in Pittsburgh

Video Pipe Inspection Services Helping to Map City’s Aged Wastewater Infrastructure

GPRS Video Pipe Inspection Services uncovered a completely collapsed sewer pipe while assisting the City of Pittsburgh, Pennsylvania, as it works to overhaul its aging wastewater infrastructure.

GPRS Project Manager Nate Johnson is investigating and mapping 70,000 linear feet of small-diameter, combined sanitary and storm sewer pipes across the city for a contractor tasked with replacing the current infrastructure with separate wastewater and stormwater systems. Johnson explained that the existing lines range in age from 50 to 120 years old, and the only existing records of the system are similarly out-of-date.

“All we have are maps to go on, and a lot of the maps are not right because they are from the early 1900s,” Johnson said. “So, we’re correcting the maps… [and] we’re inspecting all these sewer lines for rehabilitation, so they know where and how to fix them.”

GPRS Video Pipe Inspections utilize CCTV camera-equipped, remote-controlled rovers and push-fed scopes to investigate sewer and stormwater pipes for clogs, cross bores, and other structural defects & damages. Our NASSCO-certified Project Managers provide comprehensive, interactive reporting that details every inch of your pipes to help you plan repairs, maintain your system integrity, and mitigate risk.

As we’re investigating your sewer system, we can also map it for future operations & maintenance (O&M) purposes. Our rovers and push-fed scopes are equipped with sondes: instrument probes that we detect from the surface using electromagnetic (EM) locators to map your system while we’re searching for faults.

All this field-verified data is at your fingertips 24/7, from any computer, tablet or smartphone, thanks to SiteMap® (patent pending), GPRS’ cloud-based infrastructure mapping software solution that provides accurate existing condition documentation to protect your assets & people.

“Obviously, SiteMap® is a huge thing for this site,” Johnson said. “We can give the contractor the map, and that way the city can update their own maps and have more accurate information.”

Most of Pittsburgh’s system consists of vitrified clay pipe, a type of pipe made from a blend of clay and shale that has been converted into a glassy substance (vitrified) through heat and fusion.

Vitrified clay pipe is like clay pottery in that it’s hard to crush, but it will snap when not properly supported or when placed under extreme pressure from an external source such as a tree root or another buried utility. That’s exactly the situation Johnson discovered in Pittsburgh, as you can see below:

Trash and other debris inside a collapsed sewer pipe.
GPRS Project Manager Nate Johnson discovered this completely collapsed sewer line while investigating the City of Pittsburgh’s combined sewer system.

“No one had any idea that pipe was like that,” Johnson said. “The pipe was completely blocked due to the collapse… [Vitrified clay pipes] are very susceptible to breaking if you get close to them. They’ll pretty much last forever if they’re not disturbed, but if a project occurs near or around them and it doesn’t go as planned, and they get too close, then they’re really susceptible to cracking, and breaking, and collapsing.”

Johnson said that the wastewater and stormwater that leaked out of this broken pipe likely compromised the integrity of the surrounding soil.

“Any liquid takes the path of least resistance,” he explained. “This isn’t a new break – it’s been there for a long time, so there’s potential for large voids in the soil around it, which could cause sinkholes.”

The best way to prevent collapsed sewer pipes and other defects from compromising your system is to hire a professional sewer inspection service to conduct sewer pipe inspections both before and after any excavation work occurs around a wastewater system.

“In a lot of the breaks that we find, it’s maybe a water line was fixed on top of it, or a new gas line was put in on top of it and the vitrified clay pipe gets crushed from the machinery or [the new line],” Johnson explained.

Combined vs. Separate Sewers

Most U.S. communities today have separate sanitary sewer systems, according to the United States Environmental Protection Agency (EPA). One set of pipes collects wastewater from homes and businesses and carries it to a wastewater treatment plant through sanitary sewers, while a separate set collects stormwater from drains at the end of driveways, around parking lots, and along streets and carries it to a local waterway through municipal separate storm sewer systems.

In a combined sewer system, both wastewater and stormwater flow through the same pipes. In dry weather, all wastewater flows to a wastewater treatment plant where it is treated before being discharged to a waterbody. During wet weather, however, stormwater enters the system.

The combined flow of wastewater and stormwater can overwhelm a combined sewer system, which is why permitted outfalls are located throughout the system to act as relief points during wet weather. These outfalls discharge untreated or partially treated stormwater and wastewater into nearby waterbodies. These discharges are called combined sewer overflow (CSO) discharges, and they are a major water pollution and public health concern because they can contain bacteria, debris, and other hazardous substances that can be harmful to people, pets, and wildlife.

According to the EPA, there are approximately 700 communities in the United States that have combined sewer systems and experience combined sewer overflow discharges. Most of these communities are located in the northeast and around the Great Lakes – the source of drinking water for more than 40 million people in the U.S. and Canada, and home for more than 3,500 plant and animal species, some of which are found nowhere else on Earth.

The Clean Water Act (CWA) requires communities with CSOs to put controls in place to address these concerns. But the best way a municipality can mitigate the dangers of CSOs is to follow in Pittsburgh’s footsteps and overhaul their wastewater infrastructure to separate wastewater and stormwater flow.

“We help with a lot of projects like this, where [a municipality] is trying to get their wastewater and stormwater systems separated,” Johnson said.

A GPRS Project Manager lowers a sewer inspection rover into an open manhole.
GPRS Video Pipe Inspections utilize CCTV camera-equipped, remote-controlled rovers and push-fed scopes to investigate sewer and stormwater pipes for clogs, cross bores, and other structural defects & damages.

GPRS Keeps Your Infrastructure Working for You

Hiring a professional sewer scope inspection service is a crucial step toward ensuring the success of any wastewater infrastructure improvement project. GPRS provides industry-leading sewer scope inspection services along with a suite of other infrastructure visualization services and products designed to keep your infrastructure working for you.

From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep your projects on time, on budget, and safe.

What can we help you visualize? Click below to schedule a service or request a quote today!

Frequently Asked Questions

What size pipes can GPRS inspect?

Our elite Video Pipe Inspection Project Managers have the capabilities to inspect pipes from 2” in diameter and up.

Can you locate pipes in addition to evaluating their integrity?

Yes! Our SIM and NASSCO-certified Project Managers use VPI technology equipped with sondes: instrument probes that allow them to ascertain the location of underground utilities from an inaccessible location. This allows them to use electromagnetic (EM) locating to map sewer systems while they’re evaluating them for defects.

What deliverables does GPRS offer when conducting a VPI?

GPRS is proud to offer WinCan reporting to our video pipe inspection clients. Maintaining sewers starts with understanding sewer condition, and WinCan allows GPRS Project Managers to collect detailed, NASSCO-compliant inspection data. GPRS Project Managers not only inspect the interior condition of sewer pipes, laterals, and manholes – they can also provide a map of their location. The GPRS Mapping & Modeling Department can provide detailed GPS overlays and CAD files. Our detailed WinCan/NASSCO reports contain screenshots of the interior condition of the pipe segments that we inspect, as well as a video file for further evaluation, documentation, and/or reference.