Ovarro-Northumbrian leakage trial achieves nightline target

Northumbrian Water, which supplies water to 2.7 million people in north-east England, is aiming for an 8% reduction in leakage in AMP8 - 2025-30 - with a long-term target of 55% by 2050, from its 2017/18 baseline, writes Paul Hol t, Ovarro leakage product specialist  

The company’s revised draft Water Resources Management Plan 2024 says innovation is key to achieving its goals, and pledges to use new technology to make its network smarter to identify leaks more quickly.   

As a result, Northumbrian Water is undertaking a range of feasibility studies and trials ahead of AMP8, including one with Ovarro. The results will be used to inform future leak detection investment and strategy. 

The solution    

In November 2023, Northumbrian Water partnered with technology company Ovarro to trial LeakNavigator, an end-to-end, fixed-network leak detection service. The three-month trial covered the Fish Quay district metered area (DMA) in the town of North Shields, which serves nearly 1,400 properties via 17km of water main. 

Northumbrian Water set a target for the trial to achieve a historic nightline minimum of 7.6m3/h, maintaining this level after project completion.  

The LeakNavigator package comprises a fully-managed analytics platform, acoustic dataloggers from Ovarro’s Enigma range and access to its in-house leakage expertise. The service identifies points of interest (PoIs) on behalf of water companies and directly alerts field technicians via a mobile app, reducing the need for in-house data analysis.  

The LeakNavigator end-to-end service includes a pre-assessment of the targeted DMA by Ovarro’s leakage analysts, and ongoing data analysis once the loggers are in operation.  

Thirty-six loggers were installed for Northumbrian Water’s trial, a combination of models Enigma3-BBs and Enigma3hyQs. Both models are correlating acoustic loggers, fitted with a sensitive hydrophone sensor to measure the sound generated by leaks, usually overnight, and feed data into the analytics system.  

The Enigma3hyQ is typically installed on a hydrant or valve. The Enigma3-BB is installed on a property meter box chamber, which simplifies the process, as meter boxes are easier to reach than hydrants. It also provides more network access points to the network, increasing logger coverage. 

The loggers were selected due to ease of deployment and proven capability in finding leaks on plastic pipes – an enduring challenge for water companies, as sound does not travel well on plastic. As more ageing metal pipes are replaced with plastic, the scale of this challenge is set to increase.  

In week one of the trial, when PoI follow-up visits did not result in the expected number of leaks being found, Ovarro arranged additional training for technicians. Engineer Paul Holt spent two days onsite, closely guiding the Northumbrian Water team through the end-to-end LeakNavigator process. After training, the technicians picked up more leaks, much faster.  

Results   

Five sizeable leaks were found during the trial, with a conversion rate of 80%. They included a major leak found on an 8-inch (203mm) PVC water main.  

Northumbrian Water’s normal detection techniques for the DMA had not found the leak, which was estimated to have been running for approximately 12 months. Flow data shows the leak was losing at least 5.5l/sec water, which is 475 m3/day, and would have amounted to 171 megalitres over 12 months.    

A second large leak was found on a business customer’s private pipe. Once both leaks had been repaired, the target nightline figure was achieved, and as of July 2024, had been sustained.  

Andrew Blenkharn, Northumbrian Water’s technical policy manager, said: “The purpose of the Ovarro trial was to understand what our options are to deliver leakage reduction in AMP8 and to explore the feasibility of permanent logging. For us, the technology was quick to deploy and proven to work, delivering excellent results.  

“I was particularly impressed that it found the big leak on the PVC main, which would not have been found otherwise. Leakage had been increasing for a while in this area and the leak had not been picked up by normal methods.  

“Overall, we got down to the historic minimum level we were aiming for and had confidence that if any leaks did break-out in future, we would have been able to respond to them quickly, if the loggers were kept in.  

“As leakage gets more difficult to drive down, permanent logging, particularly on plastic, becomes more of a viable option for the future. For Northumbrian Water, leakage will remain a big focus and this is just the start of our efforts to drive down levels in AMP8.” 

Taxonomy

• Water