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Case Study

City of Montréal, Québec

The City of Montreal supplies drinking water and wastewater services to a population of nearly 1.9 million people. Starting in 2007, Pure Technologies (Pure) began working with the City’s potable water transmission division on a pipeline assessment program that included electromagnetic (PureEM) inspection and acoustic monitoring.

In 2015, as part of a pre-emptive program to reduce loss of non-revenue water and understand the condition of their pipes, the City partnered with Pure to conduct an ongoing, three-year leak detection survey on a series of critical pipes within its potable water network located mostly in the downtown core.

Project Details

Services
 Sahara® leak detection

CCTV visual inspection
Timing
 2015-Ongoing
Pipe Material
 BWP, Steel, Cast Iron, PCCP
Inspection Length
 28.9 km (18.5 m)
Diameter
 500mm – 1200mm (20-inch – 48-inch)
Transmission Type
 Water

Project Highlights

20.8 miles (33.5 kms) inspected to date

46 insertions completed

24 leaks identified

9 leaks identified as feature leaks

Challenge
The City recognized the value of detecting leaks, however small, to prevent these from developing into greater problems. While leaks occur most frequently on small-diameter distributions mains, leaks and ruptures on trunk mains are a much bigger concern for utility operators due to the relatively higher consequence of failure.

In addition to physical losses of water caused by a series of small leaks, the escaping water can eventually erode the surrounding soil making the area more prone to washouts or sinkholes, a major headache especially in densely populated areas. Leaking water can eventually find its way to the surface, or into sewers, overburdening the system. Unplanned excavations to repair unforeseen leaks can also erode consumer confidence in a public utility.

Solution
For its multi-year leak detection program, the City requested Pure to deploy its highly reliable and precise Sahara® acoustic video inspection on 46 kilometers of pipelines chiefly in the downtown core. The pipeline sections consist of PCCP, BWP, cast iron and steel.

The Sahara platform comes with a variety of sensor tools to perform the inspection. This includes an acoustic sensor to perform leak and gas pocket detection, and high-resolution video camera to assess internal pipe conditions.

Because the Sahara tool is drawn by product flow via a small drag chute, and is tethered to a data acquisition unit on the surface, it gives the operator close control to confirm suspected leaks, gas pockets and other visual anomalies. The tool can visually confirm pipe irregularities, continuously recording, allowing for both real-time and post-processing analysis.

For the Montreal project, the purpose of the Sahara inspection was to assess the condition of the pipeline by identifying and locating leaks, pockets of trapped gas and to identify larger visual anomalies utilizing Closed Circuit Television (CCTV) footage collected during the inspection. The data would help shape the rehabilitation urgency and timing.

 

Results
To date, Sahara has had 46 insertions and a total of 33.5 kilometers (20.8 m) have been assessed. Analysis of the data identified 24 leaks and zero (0) gas pockets in the pipeline sections inspected. The Sahara sensor was tracked above ground using the Sahara Locator® device to track the Sahara tool and locate any potential leaks or anomalies found.

 The assessment is proving its worth from a verification viewpoint, and the leaks have been either repaired or addressed for prioritization. The current program is scheduled for completion by 2017.

With its pre-emptive leak detection program, the City is Montreal is a great example of a smart water manager taking proactive efforts at keeping its network in healthy shape.