Results of an urban water distribution network performance evaluation attempt in Greece

Abstract

The need for efficient water resources management is currently more pressing than ever, considering population growth and increased reliability requirements, under climate change conditions. On average, one-third of the total water abstracted for urban uses is being lost due to leaks and breaks occurring in water distribution networks. This means that significant amounts of water and revenues are being lost, forcing water utilities to consider developing effective water loss and Non-Revenue Water reduction strategies. Additionally, all water utilities operating in EU countries should, by the end of 2010, develop and implement appropriate water pricing policies that will guarantee the recovery of the full cost of the water being used. This strict obligation makes the reduction of water losses an even more urgent goal that the water utilities have to achieve. The first step towards all the above-mentioned goals is to safely evaluate the performance level of the water network. Thus, the IWA Task Forces on Water Losses and Performance Indicators (PIs) developed specific tools (e.g., the standard international water balance and various PIs), to help water utilities use a common language that will assist know-how and experience exchange through an effective benchmarking process. The paper presents the results of using the above-mentioned IWA tools, in the case of the Larisa city water distribution network in Greece. This is the first time that such an attempt has taken place in Greece. During this process, the problems faced and the ways to tackle them are analyzed, focusing on the role of key factors that had to do with local conditions. Larisa's results are compared to data available from similar cases. Sensitivity analysis was used to check the impact of the variables' uncertainty to the results. Finally, water loss reduction measures are proposed towards an effective pressure management strategy and a proactive pipe maintenance policy based on safely estimating the pipes' optimum replacement time.

Keywords:

• urban water distribution networks
• water balance
• PIs