A District Metered Area (DMA) is a discrete part of a larger Water Distribution Network (WDN). Many water companies create DMAs to allow network operators to manage the system more effectively. DMAs are then monitored, and a Water Balance calculated to provide information on where to prioritise efforts in Non-Revenue Water (NRW) reduction. Prioritisation of Active Leakage Control (ALC) and the types of activities required to reduce NRW can be inferred by the status of a DMA.
Using a data driven analytical approach, NetAlytics automatically classifies DMAs into one of six categories based on current and historical data and displays supplementary information that can be used in the investigation stage.
The six categories are:
1. Reactive
2. Recovery
3. Reduction
4. Unavailable
5. Non-Operable
6. Unmonitored
A Reactive DMA classification is when a network operator would need to react to a sudden breakout on the WDN highlighted by a significant rise in the DMA nightline. Supporting information can be utilised to narrow down the location of the outbreak such as customer contacts (e.g. no water/low pressure). Sensor data is also used to localise an outbreak, such as fixed network acoustic loggers or smart meters reporting any new alarms that coincide with the breakout period. Additionally, if the DMA has been split into smaller leakage control areas (LCAs) then this too narrows down the area required to carry out ALC activities. Based on the available data the investigation may focus solely on points of interest (POI) follow-ups or a broader sounding survey of the DMA. In many cases, bursts are visible and can be identified and repaired quickly, allowing the DMA to return to its normal level of leakage.
A Recovery DMA is when leakage has gradually risen over time, eventually reaching a level where a leakage sweep is required. Typically, this increase is a result of multiple leaks both main and customer side. Several techniques can be applied based on the DMA characteristics and attributes meaning campaign surveys are typically longer than a Reactive DMA survey dependent on the size of the DMA. When the leaks identified are repaired the DMA should return to what is referred to as its “exit level” when detection teams are no longer required in the DMA. In addition, larger DMAs where surveys are taking a long time to locate leakage, network operators can create LCAs within the DMA to make smaller discrete areas within the DMA to help with prioritising the area to focus ALC.
A Reduction DMA classification is when leakage has been consistently high in a DMA for an extended period or if the leakage has never been as low as the area characteristics indicate it could be. In these cases, more specialist detection activities are required to reduce leakage. These could include subdivision of the DMA through LCA creation (long term activity) or Step Test activities (short term activity). Both can assist in identifying the spread of leakage within the DMA and where to focus ALC and assist in shortening the location time of the leaks. After the reduction campaign, the DMA’s leakage should be lower, and a new "exit level" will be established to serve as a target for future monitoring.
Unavailable, Non-Operable, and Unmonitored DMA classifications indicate underlying issues within a DMA that prevent leakage from being calculated and therefore an estimated leakage value is used. To address this, improvement works are typically required to enable the DMA to attain a calculated leakage figure. While these improvements are underway, such DMAs are regularly targeted using standard techniques like sounding and noise logging to manage leakage effectively.
At Crowder Consulting, we are committed to helping our clients improve their water leakage management to reduce losses and cut costs. To find out more, please get in touch today.