Pressure-Based Analysis of Water Main Failures in California

Abstract

Frequent, extended, and high fluctuations of internal water pressure are suspected to be causally linked to water main failures. However, there is little solid quantitative evidence to support this for real water systems. This paper examines the influence, extent, and impacts of hydraulic pressure magnitude(s) on the physical integrity of water mains in five selected districts in California. The principal objectives of this study were to: (1) characterize spatial and temporal patterns of relatively high water main failure rates, and (2) statistically test for direct correlative linkages between observed high local pressure regimes and pipe failures. To accomplish these goals, eight years of data from the utility’s annual pressure survey (APS) was collected and analyzed. Areas with a consistently high failure rates showed notably stronger correlations between two variables, which reflects the role of pressure on increased failure rates and likely development of failure clusters. Weaker correlations, however, were observed when analyzing the entire district and nonfailure hotspots. These results can contribute to the development of more comprehensive long-term programmatic water main planning and management strategies.