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According to the Association of Civil Engineers 2017, the Infrastructure Report Card estimated that the United States loses around 2 trillion gallons of treated drinking water each year. The report highlights the demand for evaluation, maintenance, and repair of distribution systems in the US.
In light of this finding, the Federal Energy Management Program (FEMP) identified a few effective leak detection technologies that can assist the federal agencies in detecting and repairing all types of water leaks.
This article discusses the leak detection technologies used for small-to-medium and large distribution systems as per FEMP.
Contents:
Leak Detection Technologies for Small-to-Medium Drinking Water Distribution Systems
A small-to-medium drinking water distribution system supplies water to a single building or a small set of buildings. The leak detection technologies used for small-to-medium distribution systems are:
1. Noise Loggers
Noise loggers make use of acoustic leak detection technology. Here, the sound waves are used to detect leaks in the pipe system. A small leak produces a high-frequency sound, and a large leak produces a low-frequency sound.
A noise logger is attached magnetically along with the distribution system and left in place for longer periods to record the noise levels and finally detect the leaks. The system has a sensor with a listening head and a digital recorder.
2. Listening Sticks
Listening sticks are acoustic-based hand-held devices used to manually check the leaks in a distribution system. These are used to check the leaks in exposed pipes or contact points like hydrants, meters, valves, etc. This method requires additional procedures to detect the exact location of the leak in the system.
3. Hand-Held Thermal Imaging
Hand-held thermal imaging technique detects water leaks in a pipe system by detecting the subtle temperature differences and patterns that reveal the presence of water. For example, if the water temperature is around 40°F-70°F, the leaks are found to be warmer in winter and cooler during summer.
Leak Detection Technologies for Large Drinking Water Distribution Systems
Large distribution systems supply water throughout a large campus. The leak detection technologies used for a large system can be employed individually or in combination.
1. In-Pipe Sensors
These are tethered or free-floating sensors used in water lines that use GPS data to digitally map the pipe system during inspections. The device can be either an acoustic, pressure or electromagnetic sensor that ultimately provides the locations of leaks on generated maps of pipelines.
2. Fiber Optics
Fiber optics monitoring lines detect leaks in prestressed concrete cylinder pipe (PCCP) lines. Here, the breaks or damage in reinforcing steel wires used in the concrete pipes are detected. This method detects the wear in PCCP pipes but does not specify the exact location of the leak.
3. Satellite
Satellite carrying radar sensors scan an area and detect leaks in pipes placed below the ground surface. The method is suitable for sites with detailed Global Information System (GIS) pipeline data.
4. Ground Penetrating Radar (GPR)
A ground penetrating radar (GPR) sends electromagnetic waves into the ground, and the reflected waves from the objects below are recorded. The waves reflected from a water body or a leak are observed as different waves. The returned data are interpreted by a trained professional to finally determine the location of the leak.
5. Drone-Operated Thermal Imaging
Drone-operated thermal imaging technology is used to measure the soil temperature differences. Similar to normal thermal imaging, if the water temperature is around 40°F-70°F, the leaks are found to be warmer in winter and cooler during summer.
This method is used for long transmission pipelines buried undergrounds or in the fields.
The technologies discussed are commercially available and potentially lead to significant water savings.
FAQs
The leak detection technologies used for a large water distribution system are:
1. In-pipe sensors
2. Fiber optics
3. Satellite
4. Ground penetration
5. Drone-operated thermal imaging
Noise loggers make use of acoustic leak detection technology. Here, the sound waves are used to detect leaks in the pipe system. A small leak produces a high-frequency sound, and a large leak produces a low-frequency sound.
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