NRW as % of SIV fails again


CASSA: A Romanian NRW

 Reduction Success Story

But not if % of SIV is used to assess progress!

How much longer must professional NRW and leakage management specialists suffer from having their targets and performance assessed using a performance indicator which simply doesn’t work anymore? After considering yet another NRW success story which is being undermined by use of NRW as a % of System Input Volume as a KPI for assessing progress, this blog suggests possible motivations of individuals, national and international organisations which continue to use % of system input volume to set targets, monitor progress and try to compare performance in NRW and leakage management.

First, consider yet another example of a successful multi-year effort to reduce NRW – this time in a previously deteriorated distribution system in Eastern Europe, published in pages 35-41 of ROM AQUA NR. 6/2017, AN XXIII, VOL. 120. Over a 10 year period 2007 to 2015, some 300 million Euros were invested in the CASSA (Compania de APA Somes S.A) water supply systems in Romania. Improvements included bulk metering, replacement of customer meters, procurement of leakage detection equipment, procurement and implementation of GIS, hydraulic modeling, SCADA systems and training of operators. The number of systems increased from 45 to 212 to include many small water supply systems. Although mains length (+125%) and number of service connections (+107%) both more than doubled:

• system input volume reduced from 70.4 to 62.7 Mm³
• metered consumption reduced from 35.7 to 32.4 Mm³
• Non Revenue Water reduced from 34.7 to 30.3 Mm³, 65.2 to 25.2 m³/km of mains/day and 1833 to 771 litres/connection/day
• Infrastructure Leakage Index reduced by 40% from 27 to 11

So by 2015 more than twice the size of system was being supplied by 9% less volume input than the original system in 2007, and NRW volume (per connection or per km, recommended for setting targets and tracking progress in the 2015 EU Reference Document) had been reduced by 60%; an impressive performance.

 Fit for Purpose’ leakage Performance IndicatorsSummary of recommendations in EU Reference Document ‘Good Practices on Leakage Management 2015′

Unfortunately, however, in Romania NRW performance is still being assessed using % of System Input Volume (SIV), and

NRW as % of SIV fell by only 1%, from 49.3% to 48.3%

Imagine being a professional NRW manager or consultant working for 8 years to achieve the CASSA success story so far, only to realise that your performance on a 300 million Euro project is being judged using a seriously flawed KPI. You could be justified in thinking that your skills are not being appreciated, and ask yourself what is the point of trying to actually reduce NRW volume in Romania?

However, it is clearly the use of the performance indicator NRW as % of SIV that failed, not the NRW management program! Many similar international failures of this KPI are documented and are the usual consequence, rather than the exception, when using NRW as % of SIV. In fact, as modern NRW management now aims to reduce both consumption and apparent (commercial) losses and leakage, failure is inevitable as the ‘Zero-Sum’ concept applies. If volumes of metered consumption and NRW are both reduced, only one of them can decrease in terms of % of SIV; the other must increase by the same % of SIV.

This is because NRW % of SIV plus consumption % of SIV must always equal 100% of SIV, which can be easily demonstrated using the CASSA data in the ‘Play the NRW % game’ free software which is also available in Romanian language.

This is always a Zero-Sum calculation: one reduces by X%, the other increases by X%, or vice versa, or they are both 0%. In this example a 1% increase in metered consumption as % of SIV means that NRW as a % of SIV must decrease by 1%. The true volumetric % changes in metered consumption (-9.2%) and NRW (-12.8%) are quite different to the false changes in metered consumption (+1.0%) and NRW (-1.0%) expressed at %s of SIV.

It is quite common now, when attending Workshops and Conferences on NRW, to hear statements such as
‘Everyone knows %s of SIV must not be used for target-setting and/or making technical comparisons’ (IWA PI 2017 Conference, Vienna, 2017)

‘Everywhere we see NRW targets set as % of System Input Volume which is always a mistake but it is totally useless in the case of intermittent water supply’ (IWA Water Efficient Bath July 2017)

‘I’m going to show NRW as % of SIV but I know it can be misleading’ (IWA Workshop Denmark, 2017).

So what is it that motivates anyone to continue to promote NRW as % of SIV as a performance indicator? Readers of this blog may wish to consider the following possibilities; if I missed any important ones, please Contact Us.

In Post-truth society, debate is largely based on appeals to emotion, disconnected from details of policy, with the repeated assertion of talking points in which factual rebuttals are ignored – rendering truth of secondary importance.

These many challenges of water supply this century are too important to accept ongoing use of known flawed KPIs for NRW and its components. If you are a NRW water professional who is ready and willing to meet the challenges, are you also prepared to speak truth to power, and try to change what needs to be changed?

If you would like to consider joining the 132 professionals from 24 countries who have already volunteered to become part of the Professionals abandon Percentages initiative then please register your support. The more who join, the stronger will be our collective voice, and the quicker NRW as % of SIV will likely become superseded as a KPI.

Insanity has been defined as repeating the same mistakes and expecting different results. Mencken proposed that ‘For every complex problem, there is a solution which is simple, neat and wrong’, and NRW as % of SIV is a good example of this. If this KPI worked, we would happily use it; but it doesn’t, so we don’t.

Allan Lambert
13th October 2017

Acknowledgements and thanks to Iulia MIHAI and Călin NEAMȚU, ROM Aqua Magazine and Romanian Water Association for permission to show their paper on LEAKSSuite.

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