Town of Flower Mound proactively assesses water main with Sahara® leak detection tool

Flower Mound Sign

Named for a prominent landmark mound with more than 175 species of wild flowers, the Town of Flower Mound is ranked as one of the ten best places to earn a living and raise a family in Texas.

To complement these natural and economic positives, the scenic Town of 70,000 is also known for its municipal water stewardship and proactive approach in maintaining the quality of its buried infrastructure. This includes 430 miles of water mains and 230 miles sewer pipes serving 22,000 residential and industrial connections.

As part of the ongoing program for condition assessment of its buried infrastructure, the Town recently retained the services of Pure Technologies U.S. Inc. (Pure) to conduct a Sahara® leak and gas pocket detection inspection of approximately 21,200 feet of the Potable Water Main (PWM), which connects the Pintail Pump Station to the Waketon Water Tower. Constructed in 1973, the critical section of 20-and 30-inch pipeline is comprised of bar-wrapped (AWWA C303)steel and ductile iron pipe.

“Most pipelines are designed for 50 to 75 years expectancy, and service life can vary depending on factors such as depth, soil conditions and pipe material,” said Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District. “Rather than waiting for breaks to happen, the Town strives to assess the condition of the assets before that happens.”

The Sahara inspection followed a structural assessment using a PipeDiver® inspection of this same pipeline conducted one month earlier and covered many of the identical pipeline sections. FMPW chose CCTV inline video and enhanced electromagnetic (EM) assessment to provide a comprehensive condition assessment.

PipeDiver platform carried to the insertion point

Pure’s free-flowing PipeDiver platform, which preceded the Sahara inspection along the same pipeline, is being carried to the insertion point.

Detecting small leaks with Sahara inspection platform

The Sahara® pipeline inspection platform is one of the most accurate tools available for leak detection, gas pocket detection, and locating structural defects in complex networks of large diameter water and wastewater pipes.

The tethered tool is capable of locating very small leaks typically within 1.5 feet (0.5 meters) of their actual location. The tool also features inline video that allows operators to observe internal in-service pipe conditions.

Added value: Flower Mound inspection included design and installation of taps

The insertion locations for the Sahara inspection were dictated by the previous PipeDiver inspection, which indicated a large number of bends and long distances to cover with less than ideal access.

In light of the limitations, and within a very short time frame, Pure took on the responsibility to manage the tapping process in-house, including the design, excavation and installation of the taps to insert and extract the Sahara tool from the pipes. Although this task was atypical of work normally provided, it is an example of the added value Pure can bring to a project.

Detected: one leak, one large gas pocket, plus improved GIS information

It’s still early in game, and the electromagnetic results have yet to be fully evaluated. Nonetheless, the Sahara inspection detected a leak on an undocumented offtake installed on pipe suspected to have been blanked off and buried, and now leaking.

In addition to pinpointing the leak and gas pocket, the condition assessment located an additional six undocumented outlets the Town was previously unaware of, leading Pure and FMPW to surmise that the outlets were installed and equipped with blind flanges for future expansion. Additionally, during this inspection, sections of pipeline alignment were discovered to be quite different than what FMPW expected.

FMPW now has a true comprehensive condition assessment of their pipeline that includes GIS quality mapping, video inspection and recording of the pipeline interior, leak and gas pocket identification and repair, and assessment of the structural integrity on a pipe-by-pipe basis — allowing for localized verification and repair. Overall, GIS information has been improved, with location and images of possible leaks, defects or anomalies.

“The proactive approach we’re taking allows us to predict water main breaks, which improves our reliability of service,” said Williams. “When you locate a defect, you can schedule a repair, notify people, and get it done at the right time of day, and at a schedule of our choosing. Everybody benefits.”

Randy Williams, Utility Services Manager of Flower Mound Public Works (FMPW) District, talks about the Utility’s approach to condition assessment.