Decision method for rehabilitation priority of water distribution system using ELECTRE method

Abstract: The water pipe is an important component of the tap water facility, and plays a role as critical as that of the blood vessel in the body. However, accurate diagnosis of its condition is very difficult because it is buried under the ground, even as pipe aging frequently leads to phenomena that threaten water quality such as pipe damage and water leakage. In order to maintain and improve the performance of the existing pipe network, planned examination, operation, and maintenance, as well as technologies for proper renewal, are required. Accordingly, the present research proposes a method that can be used for the maintenance of the pipe network in each water distribution block (WDB). For this purpose, the weighted performance indicator (PI) determined by means of PI and the analytic hierarchy process technique which allows evaluation for individual water WDBs, was applied to the ELECTRE technique which is a multi-factor decision-making method. This result may be used as a reference for water leakage maintenance and for the renewal and change of a WDB. The frequency of pipe accidents is expected to be reduced by appropriate plans set up beforehand. The research was conducted by investigating the 60 WDBs of both Sujeong-Gu and Joongwon-Gu in Seongnam City. The water pipe rehabilitation ranking of the 60 WDBs could be determined as a result. In order to determine the best R model out of the 16R models, a comparison was made of the correlation coefficient, rate of ranking conformance, mean square error, and mean absolute error. The result showed that the R12 model was the most suitable model, while the priority in the maintenance of the pipe network for each block could be determined. As a result, the blocks least suitable for first maintenance were determined to be Blocks 22, 48, 38, 18, and 32, whereas the most satisfactory ones were Blocks 42, 55, 23, 12, and 41.