The population’s water supply is managed by Davao City Water District (DCWD), which has been challenged to reduce non-revenue water (NRW) losses by 1% per annum until it reaches a target of 20% NRW. Groundwater has historically been the city’s main source of water, but increasing pressures deriving from population growth and urbanisation means there is a need to limit abstraction and make supplies more sustainable.
For utilities like DCWD, reducing demand for water by cutting NRW is a key part of long-term supply planning. The district has invested in advanced correlating noise loggers from Ovarro’s Enigma range – 260 of the Enigma3m model and 60 of the Enigma3HyQ model – as part of its drive to secure future water supplies.
Significant savings
The loggers have been provided and are supported locally by Ovarro’s partner in the Philippines, Eastasia Solutions Technologies Corporation. In the week after installation in mid 2022, the Enigma3m correlating loggers identified a point of interest in an area that had been scanned with ground microphones several times before, and where there was no surface evidence of any leak.
Putting the Enigma3m to the test, the DCWD team dug up the road and uncovered a leak with an estimated flow rate of over 1,000m3 per day. Once repaired, the surrounding suburb experienced a 15PSI rise in water pressure.
Further investigation by DCWD showed there had been no significant drop in pressure since records of pressure had been kept. This led DCWD to believe the leak could have been flowing for at least 10 years, costing them more than 25 gigalitres – that is 25 billion litres – in lost water.
The savings for DCWD associated with repairing the leak are considerable. At more than 1,000m3 per day, the volume of water saved allows DCWD to push back plans for the new production well, along with significant financial outlay.
This may have included spending on licencing costs, construction of the well and any water treatment and storage facilities required, along with transmission pump and pipeline assets. Pausing the project means a significant reduction in cost and environmental impact for DCWD.
Correlating noise loggers
Enigma correlating noise loggers gather sound samples for analysis by for analysis by the cloud-based analytics tool LoggerVision, which allows users to visualise and review the data collected. The Enigma3m and Enigma3HyQ are designed for remote deployment, and use an integrated battery and 4G modem to provide daily samples of pipeline noise for up to five years.
With 50 Enigmas in a district metered area (DMA), up to 1,225 correlations can be performed every day, analysing pipeline noise for evidence of leaks. A leak will generate vibrations in the pipe material that is collected by an Enigma3m via an accelerometer.
In the case of softer plastic materials, noise attenuates quickly, so an Enigma3HyQ, with its integrated hydrophone is preferred. Daily analysis excludes any ambient interference and pinpoints significant noise sources between loggers to provide the precise location of leaks in water distribution networks.
Change in approach
The engineer in charge of DCWD’s active leakage control team told Ovarro he had seen a change in approach towards leak detection in his crew. He explained that his team had previously walked the streets of Davao City with ground microphones.
He said, Now, with a precise point of interest and evidence from the Engima3m loggers, the team go to the location and do not return until they have an explanation for the noise – usually uncovering a new leak. It is changing the way they look at leak detection, with positive results.
Ovarro channel sales manager Craig Abbott said, DCWD’s installation of fixed correlating loggers is a first for the Philippines and we are very excited to be working with Eastasia Solutions and Davao City Water District on such an important project.
The significance of their change in attitude cannot be understated. DCWD’s team are transforming into a professional leak detection outfit that will benefit DCWD, their community and the local environment. They are setting a fine example for all Philippine water authorities to follow.
Source: Ovarro Ltd.
