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Open AccessArticle

Monitoring Nonrevenue Water Performance in Intermittent Supply

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Department of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands
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Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands
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Water and Environment Centre, Sana’a University, Sana’a, Yemen
*
Author to whom correspondence should be addressed.
Water 2019, 11(6), 1220; https://doi.org/10.3390/w11061220
Received: 8 May 2019 / Revised: 7 June 2019 / Accepted: 7 June 2019 / Published: 11 June 2019
(This article belongs to the Section Urban Water Management)
Water utilities should monitor their nonrevenue water (NRW) levels properly to manage water losses and sustain water services. However, monitoring NRW is problematic in an intermittent water supply regime. This is because more supplied water to users imposes higher volumes of NRW, and supplying significantly less water results in an unmet water demand but interestingly less NRW. This study investigates the influence of the amount of water supplied to a distribution system on the reported level of NRW. The volume and indicators of NRW all vary with variations in the system input volume (SIV). This is even more critical for monitoring NRW for systems shifting from intermittent to continuous supply. To enable meaningful monitoring, the NRW volume should be normalised. Addressing that, this research proposes two normalisation approaches: regression analysis and average supply time adjustment. Analysis of the NRW performance indicators showed that regression analysis enables the monitoring of NRW and tracking its progression in an individual system only, but not for a comparison with other systems. For comparing (or benchmarking) a water system to other systems with different supply patterns, the average supply time adjustment should be used. However, this approach presents significant uncertainties when the average supply time is less than eight hours per day. View Full-Text
Keywords: nonrevenue water (NRW); assessment; intermittent supply; performance indicators; water loss; when-system-is-pressurised; normalisation; benchmarking nonrevenue water (NRW); assessment; intermittent supply; performance indicators; water loss; when-system-is-pressurised; normalisation; benchmarking
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MDPI and ACS Style

AL-Washali, T.; Sharma, S.; AL-Nozaily, F.; Haidera, M.; Kennedy, M. Monitoring Nonrevenue Water Performance in Intermittent Supply. Water 2019, 11, 1220.

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