TIME SERIES CHANGES IN THE INFRASTRUCTURE MAINTENANCE SYSTEM OF DRINKING WATER PIPELINES UNDER STATIONARY BUSINESS ENVIRONMENT

Abstract

 To promote infrastructure maintenance of water pipelines, proposing an efficient system based on statistical data is desirable. This study analyzes the trends in index values and correlations among variables in steady-state business environmental entities that have not merged and whose water supply area remained unchanged from FY2001 to FY2020. The study analyzed the correlation between index values and variables. It was found that utilities that demonstrated improvement tended to increase construction work during periods of rising water supply revenues. Additionally, utilities that improved their inefficiency ratio also increased the ductile pipe ratio. Finally, utilities that improved the aged pipe ratio may have benefited from a longer average employee service length.