Water Main Leak Monitoring for Construction Risk Mitigation

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Pulling the manhole cover aside, the team of pipeline leak-detection specialists from Echologics looked down into the flooded underground chamber below. A local water utility crew pumped water from the chamber, slowly revealing valves and pipe fittings connected to a pair of underground 36-in. diameter cast-iron water mains running through a major construction site near Jersey City, N.J. Peering through the open manhole, the technician carefully lowered a cable-attached surface mounted sensor device the size of a soda can, “fishing” it into place until it attached magnetically to a pipe fitting with a click.

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Known in the industry for its acoustic-based leak detection technology and expertise, Toronto-based Echologics frequently responds to water utilities grappling with hard-to-find pipeline leaks. An undetected leak in a critical large-diameter water main can quickly turn into a costly failure, and utilities often bring in an Echologics team before a minor problem turns into a major crisis. In this case, however, there was no impending water main failure, or possible pipeline leak. In fact, there was no suspected problem at all. The Echologics crew was there to provide “peace of mind.”

“With major construction projects involving hundreds of millions of dollars, it is very helpful to have one less thing to worry about,” says Evan Raab, project engineer with CCA Civil, one of the world’s largest construction companies. One of CCA’s big worries was accidentally damaging a pair of 150-year-old active water mains running right through their construction site for building the new Route 7/Wittpenn bridge over the Hackensack River.

“We are using large and heavy cranes and equipment, including enormous hammers driving 30-ft steel sheeting around each foundation and pounding steel H-piles into the ground with impacts about every five seconds,” says Raab. “You can feel the tremendous shocks and vibration, and hear the hammer impacts for miles around — and we worry about what that might do to those old water mains.”

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Commissioning proactive pipeline leak-detection surveys is common for many water utilities, but it is a new trend for construction projects. Performing leak detection surveys before and after construction — and sometimes monitoring continuously — is viewed as a valuable tool for risk management and mitigation.

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“Beyond simply finding leaks in the pipeline, the vital role of this technology in many construction projects is detecting, identifying, and notifying pipeline owners and contractors of potential pipe stress or damage associated with construction activities,” says Jeff Rice, Echologics regional sales manager. “It protects the owner of the pipeline and it also protects the contractor, because if Echologics finds an existing pipeline leak before construction begins, the contractor is not on the hook for damages, repairs, or liability.”

Echologics field engineers install a permanent leak detection node to monitor a critical water transmission main for the development of leaks during construction pile driving activity near the main.

Echologics field engineers install a permanent leak detection node to monitor a critical water transmission main for the development
of leaks during construction pile driving activity near the main.

Detecting leaks with large-diameter pipelines

With pairs of surface-mounted sensors deployed at two different locations along the water main, an Echologics field engineer tested the sensitivity of the system to ensure their equipment was successfully detecting noise transmitted through the pipeline. Confirming the system was able to acoustically determine the precise location and status of the noise, the team performed a comprehensive leak detection survey of two 36-in. water mains running through the construction site.

“The larger the pipe diameter, the more challenging it is to accurately record noises indicating a possible pipeline leak,”says Asha Budhlall, Echologics regional operations manager leading the field team at the Route 7/Wittpenn bridge construction site. “We run a full battery of system tests and simulations to ensure the most accurate acoustic data. This includes testing each pipe segment to distinguish between ‘in-bracket’ noise, or noise detected between two sensors within the pipeline, and ‘out-of-bracket’ noise, or noises occurring beyond the two sensors. It is also vital to filter the heavy traffic and construction noise occurring at this site from the acoustic data to detect potential leaks within the surveyed pipe sections.”

The Echologics system deployed in the Route 7/Wittpenn bridge project uses the company’s specialized large-diameter pipe correlator technology, involving sophisticated acoustic sensors and processing algorithms that analyze and compare data from pipeline events detected by two or more nodes on the system to identify and locate potential leaks or flow issues.

“Fortunately, there were no problems detected with these two pipelines prior to construction, and hopefully no leaks will be found when the Echologics team returns to recheck the pipelines when the construction is finished,” says CCA Civil’s Evan Raab. “The advantages of using this leak detection technology for detecting possible pipeline damage during construction projects is that it is easy and quick to deploy, and it enables nondestructive testing of the pipelines — it’s that simple.”

The EchoShore-TX permanent leak detection technology can be quickly installed in a small footprint to provide an added level of “insurance” during construction activity.

The EchoShore-TX permanent leak detection technology can be quickly installed in a small footprint to provide an added level of “insurance” during construction activity.

Continuous Leak Detection Monitoring in Las Vegas

Another water utility considering Echologics leak detection equipment for pipeline construction risk-mitigation is the Las Vegas Valley Water District. The utility serving the “City of Lights” recently installed an EchoShore-TX system for permanent monitoring of a large-diameter water main running down the middle of the famous Las Vegas Strip. Installed in the 1960s, the 30-in. diameter water main running underneath “The Strip” supplying the world’s largest hotels, casinos, and resorts has never suffered a major pipeline break — and the utility wants to ensure that it never happens.

The utility installed an EchoShore-TX system to maintain daily leak detection monitoring of the critical main, alerting them to any leaks as they are detected, enabling them to avoid a catastrophic pipe failure disrupting the number one business of Las Vegas: the gaming and resort industry.

Collecting data about the monitored transmission main, the EchoShore-TX system uploads the data at predetermined times to a secure server using a cellular network. Detecting a potential leak, the nodes capture and transmit the data to the central server for signal processing, leak location identification, and data interpretation for reporting. An alert would be issued immediately if any leak indications were detected.

RELATED: Echologics Non-Invasively Pinpoints Water Leak Underneath Large Chinese Bottling Plant

The water district discovered the construction risk-mitigation potential of their leak detection system quite by accident, when the system detected unexplained pipeline noise that suggested a severe problem with the water main.

“It looked like a major pipe failure in progress — our reaction was, ‘Oh, no!’” says Las Vegas Valley Water District engineer Ryan Benner. “We rushed to inspect the pipe location in question, and we realized that what was being detected was the sound of jackhammers working overhead.”

Benner says their technicians have detected similar construction noise near the pipeline several times since they installed the monitoring system, and that monitoring nearby construction activities and their potential impact on water mains is a side-benefit of the Echologics technology that they did not anticipate when they first deployed the system. Given the utility’s experience with the EchoShore-TX system, Benner is considering recommending a similar deployment to monitor another critical pipeline located near a major road construction project.

“It’s inexpensive insurance,” says Benner. “It offers added security, peace-of-mind, and no surprises for the contractor, the utility, or the municipality — because we all hate surprises.”

David Stewart Jones is a freelance environmental technology writer and researcher based in Toronto, Canada.

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