DBPapers
DOI: 10.5593/SGEM2016/B31/S12.016

CHALLENGES IN THE ASSESSMENT OF WATER LOSS KPIS IN LARGE DISTRIBUTION SYSTEMS. CASE STUDY OF BUCHAREST WATER SUPPLY SYSTEM

S. Perju, A. Aldea, M. Mihailovici, V. Zaharia
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-61-2 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 1, 113-120 pp

ABSTRACT
Water losses are a common characteristic for virtually every water supply system. The main factors that influences the water losses – in particular water leakages are the operating pressure, the continuous and intense mechanical stress of the pipes induced by traffic (most of the pipes are installed under the circulating space of the streets), ground pressure (both static and dynamic) and water and/or soil aggressiveness.
The distribution network of the City of Bucharest comprises a little over 2500 km of mains length and supply potable water for approximately 2.5 million inhabitants. Beside its large scale, this particular water supply system also comprises a great number of pumping and booster stations, effectively creating local supply zones in the network.
This paper will focus on the water loss KPIs most suitable for evaluating the performances of such large system over a period of 5 years, specifically when dealing with the popular trend of expressing NRW components (and in particular the leakages) as percentage of the System Input Volume in spite of more “fit-for-purpose” KPIs like the infrastructure Leakage Index and the Burst Repair Frequency for both the mains and service connections.
The performance indicators used and calculated on annually basis for a period of 5 years (infrastructure leakage index, water loss/ connection and water loss / length of mains) were compared against the Non-Revenue Water and Water Losses expressed as percentages of the System Input Volume and also compared against the minimum night flow trend and reported burst frequency rates.
The key conclusions of this study are as follows:
•the need to use multiple performance indicators over a period in order toaccurately establish the evolution trend of water losses
•the good results obtained by the Water Utility in reducing the water leakages
•the NRW as a percentage of System Input Volume proved not to be the best PIfor tracking and comparing the water loss management over a multi-annually period

Keywords: water loss, KPI, large distribution networks