Efficiency analysis and evaluation model development of water distribution system rebuilding project using DEA method

The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, while pipe aging causes water suspension accidents and the scale of such accidents is getting large. Accordingly, the Ministry of Environment has been promoting the local water distribution system rebuilding project since 2017 to build a block system, pipe network maintenance work, leak management work, etc. Related projects are being promoted. In this study, analyzed the efficiency of the improvement of the revenue water ratio according to the DEA(Data Envelopment Analysis) method-based water distribution system rebuilding project, and develop an evaluation model for the water distribution system rebuilding project using the efficiency analysis results.In this study, DEA analysis was performed by selecting 15 local governments that showed cost-effectiveness among 20 local governments that were carrying out the performance evaluation for the 2017 rebuilding project. In this study, DEA analysis was performed considering the number of DMUs secured three times or more than the sum of input and output factors suggested in Banker et al.(1984)’s previous study.The input indicators of this study are the values ​​derived by dividing the block system construction cost, pipe network maintenance cost, leak management cost invested for the local water distribution system rebuilding project from 2017 to 2020 by the lengths of the project target water distribution pipes. As the output indicators, the rate of increase in the revenue water ratio, which was changed according to the input project cost, was applied.In addition, a project cost evaluation model was developed for the improvement of the revenue water ratio by using the optimal efficiency point derived through the efficiency analysis with the effect of improving the revenue water ratio as a calculation index. For model development, multiple regression analysis was performed according to the step-selection method that included only independent variables with high explanatory power that had an influence on the dependent variable in the regression model to develop the model.As such, in this study, the efficiency analysis of local governments performing the local water distribution system rebuilding project was performed, and a project cost evaluation model was developed to improve the revenue water ratio. It is judged that the methodology and development model used in this study can be utilized in the analysis and evaluation of the project efficiency of the additional target area of ​​the local water distribution system rebuilding project in the future.