Southern sets out holistic approach to leakage

Southern Water has set out a strategy combining its leakage targets with other outcome delivery incentive (ODIs) during AMP7.

Last month, Discover Water unveiled the latest leakage rates, which showed Southern down to around 94 million litres each day.

For the coming five years Southern’s target is more onerous – with a 15 per cent reduction target. The company has said it will employ a combination of tactics to do this, including rolling out 7,000 acoustic loggers.

Phil Tapping, water demand manager at Southern, said:“There is not one tactic alone to address leakage as we would have used in the past- it’s about mains replacements, pressure management, active leakage control – that tie-in to some of our other ODIs and performance measures. If we replace water mains it will reduce discoloured water, managing the pressure will reduce the interruptions customers’ experience.”

He added: “There are lot of interconnected things that will effect leakage and whatever we do will have an impact on one of the other commitments.”

This includes work to better monitor peaks and troughs in the network and in some cases lowering pressure at night in order to alleviate stress on the water mains.

Around 7,000 acoustic loggers including 700 that operate on narrowband Internet of Things technology have been installed across the Southern network, following a trial in Southampton in Hampshire.

The logger sends out a signal about unexpected noises within a pipe. These ‘points of interest’ can be investigated to then identify as leaks.

Tapping said previous loggers had around 40 – 50 per cent success rate converting a point of interest into a true leak but now it is closer to 60 per cent.

“Other equipment within the network can mask the sound of a leak, these new loggers filter all of that out to pinpoint where a leak is. That data goes into a centralised platform with Guterman software so teams can view where the points of interest are and cross reference that with where the higher rates of leakage are.”

The new AMP cycle coincided with the start of the first full year of reporting leakage in a standardised way.

Previously all water companies had slightly different ways of reporting leakage but Ofwat has made it a directive that it should be standardised, with a fixed time of day to report leakage.

Southern updated its reporting system to cope with the data from the field to analyse and collate it on a weekly basis. Tapping said this approach is “a lot clearer and more current”.

He added: “It makes us more aware of what’s going on in the network. The programme can flag up variances and we can set up alarms when certain thresholds are reached and need examining instead of having to search through data.”

Tapping pointed to another challenge in finding and keeping experienced technicians, with fierce competition among water companies for a finite pool of resources.