Ofwat PR19 endorses UARL

Sunday, July 30th, 2017

Ofwat considers SELL leakage targets not

challenging enough

England & Wales Water Company performance

commitments to be compared to UARL

Ofwat’s PR19 consultation document ‘Delivering Water 2020: Consulting on our methodology for the 2019 price review’ proposes a fundamental change in approach to encourage England and Wales Water Companies to achieve stretching and ambitious performance commitments for leakage, in the interests of long-term Water Resources planning. For the last 20 years, Ofwat’s requirement for Companies to robustly calculate and achieve economic and sustainable leakage levels (ELL and SELL), to deliver benefits to customers, has driven the England and Wales Water Companies to their existing levels of leakage management.

A 2012 strategic review commissioned by Ofwat, the Environment Agency and Defra concluded that SELL ‘tends to maintain the status quo’, ‘does not incentivise efficiency or innovation’ and results in Companies being ‘risk averse’. Therefore, Ofwat has considered further options for stretching leakage performance commitments to PR19 and beyond. The preferred approach expects Companies to set ambitious commitments for leakage at regional or whole Company level. Companies should justify their proposed performance commitment levels against the following approaches, and justify why they have not adopted them:
• commit to achieving at least the forecast 2024-25 upper quartile levels of performance levels on leakage/property/day and leakage/km of mains/day
• companies should commit to achieving reductions of at least:

  • a 15% reduction (1% more than the largest commitment reduction at PR14)
  • the largest actual percentage reduction achieved by a Company since PR14

• companies should justify their performance commitments relative to the minimum level of leakage achievable (Unavoidable Annual Real Losses). The UARL is a measure defined in the EU Good Practices on Leakage Management 2015) of measuring ‘how low can you go?

Unavoidable Annual Real Losses

The concept of UARL and Infrastructure Leakage Index (the non-dimensional ratio of Current Annual Real Losses divided by UARL) was developed by the 1st IWA Water Loss Task (1995-99), to meet a perceived need for a more rational ‘level playing field’ approach to national and international assessment and comparison of technical leakage management performance. Ofwat has not previously chosen to use UARL and ILI as the measure does not take account of economics and supply: demand balance. Accordingly, only a few meaningful international comparisons of England/Wales technical leakage performance have previously been made using ILI. However, in practice, because UARL and ILI take account of so many other diverse factors, as shown in the Table below, some of the England and Wales Companies already routinely calculate UARL and ILI.

Source: Merks, Shepherd, Fantozzi, Lambert 2017: IWA Efficient 2017

The UARL formula is particularly suited to Water Resources planning, as it is based on a flexible component analysis of leakage (background, reported and unreported) in mains, communication pipes and supply pipes, with 24 auditable variables including frequency and duration of reported and unreported leaks, and flow rates varying with average pressure. Because the UARL equation includes average pressure, the basic UARL formula can predict in broad terms the benefits of reducing excess pressure on annual leak flow rate, assuming a linear pressure:leak flow relationship, with a FAVAD exponent N1 = 1.0 within the range recommended in PR19.

For the UK, where Ofwat definitions in PR19 will require UARL to be split into components of distribution losses (part of Water Delivered), and underground supply pipe losses after the point of delivery, it will be preferable to convert the original ‘litres per day’ formula in the AQUA 1999 paper into m³/year, as follows:

UARL (m³/year) = (6.57 x Lm + 0.292 x NC + 9.13 x Lsp) x Pc        (1)

where Lm = underground mains length (km), Nc = Number of Service Connections, Lsp = total length (km) of underground supply pipes and Pc = current average operating pressure (metres).

The principal authors of the 2015 EU Good Practices Report had full access to all of the assumptions in UARL from the lead author of this blog and another seven international practitioners, and published the UARL equation in a format suitable for fully metered European distribution systems. Equation (2) is equivalent to Equation (1) for an average communication pipe length of 4 metres.

UARL (m³/year) = (6.57 x Lm + 0.256 x Nc + 9.13 x Lt) x Pc        (2)

where Lm = underground mains length (km), Nc = Number of Service Connections, Lt = total length (km) of underground service connections (main to meter) and Pc = current average operating pressure (metres).

Section 9 of the CIWEM Policy Position Statement (2015) on Water Distribution System Leakage in the UK supports the conclusions of the EU Good Practices on Leakage Management relating to Fit for Purpose performance indicators for leakage. In a 2012 European data set with anonymous ILIs kindly contributed by 9 England/Wales Utilities, it is noteworthy that 8 of the 9 England & Wales Companies are within International Leakage Performance Category A.

UARL and ILI are widely and increasingly used internationally. The bar chart below shows some of the national organisations and countries using the approach, and which have ceased the misleading practice of expressing leakage as a % of System Input Volume.

Source: Merks, Shepherd, Fantozzi, Lambert 2017: IWA Efficient 2017

All of the authors commend Ofwat’s initiative in PR19 to include a European and international context in the proposed PR19 process of setting challenging leakage targets in England and Wales.

In order to resolve any misunderstandings which may still exist in the UK regarding the auditable assumptions, formats and applicability of the UARL equation, the lead author of this blog (who originated Component Analysis, and UARL concepts when Chair of the 1st IWA Water Loss Task Force) offers any UK Company, Group of Companies, Regulator, Auditor or other interested parties the opportunity to Contact Us for discussions or Workshops on UARL and ILI, during or after the consultation period for PR19.

Allan Lambert, UK, Principal author, EU Reference Document, Fellow IWA
Cor Merks, NL, Principal Consultant, EU Reference document, Member IWA
Stuart Trow, UK, Principal author, EU Reference document, Fellow IWA
David Pearson, UK, Independent Consultant, Fellow IWA

30th July 2017

LeaksSuite to June 2017

Wednesday, July 5th, 2017

LeaksSuite Website Outreach

Progress in April to June 2017 and new initiatives

The major upgrade of the LEAKSSuite website in Feb 2013 created a free information source for international concepts and management of Non-Revenue Water, Apparent Losses, Leakage and Pressure. During April-June 2017, User numbers rose by 2,033 (10%) to 22,230 from 185 countries, and number of Page Views reached 123,276. The overview of the website statistics to date, near the end of this Blog, shows User numbers by Google Geographical region and country. Over the past 12 months key topics of User interest are shown below. Analysis of trends in this data is used to identify new initiatives which are likely to be of greatest interest and benefit to Users. Click on the following Table and Bar Chart to expand for detailed view.

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Pressure Leak Flow Relationships

Saturday, June 10th, 2017

Updates on Applying FAVAD Concept

Hydraulic Analysis and Fast-Track Applications for Practitioners

Outcomes of collaborative research by the University of Cape Town and several international leakage practitioners, to improve both theoretical understanding and practical application of the Fixed and Variable Area Discharges (FAVAD) concept for pressure:leak flow relationships, will be publicly available by mid-September. A common basic philosophy has been used to model hydraulic laboratory studies of both leakage and intrusion flows through leak openings in pipe samples, with fast-track analysis and prediction applications for practitioners using pressure management to reduce leakage in water distribution systems.

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Pressure Transient Awareness

Thursday, May 18th, 2017

Pressure transients – seeing is believing

Hidden transients cause leaks, raise repair costs,

reduce asset life

Would you like to see what a pressure transient looks like – not just as a graph, but as a visible reality? Read on to access a startling media clip of transients generated in an above ground mains test rig, and then consider what damage may be done to underground distribution systems by pressure transients. International leakage management specialists who contributed to this blog are very well aware of the adverse effects of such events. However, many Utilities do not routinely take short-period pressure measurements to check for the presence of transients; or they may consider that if transients exist, they probably do not significantly influence leakage, burst frequency and infrastructure life.

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LeaksSuite to March 2017  

Saturday, April 8th, 2017

LeaksSuite Website Outreach

Progress in January to March 2017 and new initiatives

The major upgrade of the LEAKSSuite website in Feb 2013 created a free information source for international concepts and management of Non-Revenue Water, Apparent Losses, Leakage and Pressure. During Jan-March 2017, User numbers rose by 2,200 (12%) to 19,900 from 181 countries, and number of Page Views reached 112,800. The overview of the website statistics to date, near the end of this Blog, shows User numbers by Google Geographical region and country; key topics of User interest are shown below. Analysis of trends in this data is used to identify new initiatives which are likely to be of greatest interest and benefit to Users.

The creators of this website hoped to achieve 20,000 users, the same number of Liverpool supporters who watch from Anfield’s famous Spion Kop. It has taken us only 4 years to achieve this number. We hope that those of you who use the website, wherever you are in the world, WILL NEVER WALK ALONE with LeaksSuite available at a click to help you with your NRW management.

 

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WWi’s Top 25 Leaders 2017   

Monday, January 23rd, 2017

                                                                    

WWi READERS AGAIN

ACKNOWLEDGE

FOUNDER OF LEAKSSUITE

Water and Wastewater International magazine’s Top 25 Water Leaders Listing, now in its third year, opens 2017 by ‘showcasing leadership talent – whether it’s founding and growing a Company from scratch, or adapting a well-established Corporation to weather economic and market changes’.  This annual poll of WWi readers has voted Allan Lambert, founder of the ‘free to all’ LeaksSuite website, as 17th of Top 25 International Water Leaders, and the only UK-based individual in this year’s awards. Continue Reading »

LeaksSuite 2017 Initiatives

Monday, January 9th, 2017

LeaksSuite Website Review Jan 2017

Progress in 2016 and Two new Initiatives for 2017

The major upgrade of the LEAKSSuite website in Feb 2013 created a free information source for international concepts and management of Non-Revenue Water, Apparent Losses, Leakage and Pressure. During 2016, User numbers almost doubled, to 17,700 from 177 countries, and number of Page Views passed 100,000. The overview of the website statistics to date, near the end of this Blog, shows User numbers by Google Geographical region and country; key topics of User interest are shown below. Analysis of trends in this data is used to identify new initiatives which are likely to be of greatest interest and benefit to Users. Continue Reading »

Managing NRW – Roof Storage Tanks & Intermittent Supply

Tuesday, December 6th, 2016

Masterclass for Aguas de Saltillo with

international experts

Nov 2016, Llandudno

Some of the concepts and practical approaches now available for managing NRW become more difficult to apply when water is delivered to consumers through large roof storage tanks, rather than by direct pressure. Where supply is also intermittent, the problems of quantifying and reducing NRW are then compounded by excessive frequencies of leaks and bursts, damage to the distribution system and impairment of meters, and reduction of asset life. The recommended solution is to move to a 24/7 policy of continuous supply, but this is easier said than done. However, some Utility systems (Malta), and Malta and Cyprus case studies in with roof storage tanks have achieved continuous supply with ILIs close to, or even below, 2.0

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LeaksSuite to September 2016

Saturday, October 1st, 2016

LeaksSuite Website Outreach

Progress since 2013 and new initiatives

The major upgrade of the LEAKSSuite website in Feb 2013 created a free information source for international concepts and management of Non Revenue Water, Leakage and Pressure. Since then, a steadily growing number of Users – now 15,470 from 175 countries – are accessing this free resource. This overview of the website progress to date shows numbers of users by Google Geographical region and country, key topics of User interest, and current and upcoming new initiatives.

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Free Water Balance and KPI software

Saturday, August 6th, 2016

EurWB&PICalcs now available in Greek

As part of the co-operative effort to introduce and promote the recommendations of the EU Reference document Good Practices on Leakage Management (2015) throughout Greece, the Hellenic Water Association (HWA) has been working with the Technical Committee of the Municipal Water Works Association of Greece (EDEYA) to produce a Greek language version of the EurWB&PICalcs Water Balance and Performance Indicators free software, which is based on IWA Water Loss management practices.

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