Study of Water Pipeline Replacement Criteria for Metropolitan Area

Abstract

Water loss is one of the critical problems experienced in tap water supply in the Bangkok Metropolitan area. It is primarily caused by leakage in the water pipeline network. Thus, replacing the deteriorating water pipeline is considered a preventive measure that effectively reduces possibility of water loss problems in the long term. However, pipeline replacement needs careful planning and selection because it involves various groups of stakeholders and each pipeline may differ in build materials, ages, serviceable life span. This research specifically focused on studying the criteria for selecting and prioritizing pipelines for the maintenance water-distribution system. It used the Analytic Hierarchy Process (AHP), which is a multi-criteria decision-making technique based on pairwise comparison test. It classified the selection criteria into two groups : 1) the level of deterioration of the water-distribution system; and 2) the site access probability which indicates the chance of technicians being allowed to replace a selected pipeline. Then, it evaluated the priority of each selection criteria based on opinions from 3 specialists who had experience with water loss for more than 10 years. Once the selection criteria were developed, they were used to assess the needs to replace pipeline in 12 water distribution routes owned by the Metropolitan Waterworks Authority (MWA) for validation purposes. The validation showed that the developed selection criteria had consistent results with the actual selection made by MWA for pipeline replacement as among the 12 routes, there were 8 routes selected by MWA for replacement and all the 8 routes had a total score of more than 50%. In addition, the remaining 4 routes that were not selected were ranked lowest by the developed selection criteria and had a total score of less than 50%.