A study of the water supply system failure in terms of the seasonality: analysis by statistical approaches

Abstract

Among the many factors affecting water supply system failures are the weather conditions that change over the year. Since this is an important research issue, as part of this study, investigation of water supply system failure seasonality by the selected statistical approaches was presented. The basis of the research was monthly number of the pipelines' failures from the multi-year period of 2007–2017 of the municipal water network located in southern Poland. Mann–Kendall test results proved decreasing seasonal trend of the failure rate indexes λ. In turn, the results of the Colwell indexes' calculations allowed it to be stated that seasonal course of the water pipelines' failure events can be relatively easy to predict. As it turned out, it is difficult to determine unambiguously the impact of a given period of the year on the water pipeline failure events' occurrence. However, greater failure-free operation of the water pipelines may be expected in spring and summer months than in autumn and winter months. Because using Colwell indexes for seasonality analysis has no limitations compared to other methods, Colwell indexes may be considered as reliable tools for the assessment of the seasonal course of the water pipelines' failure events. HIGHLIGHTS Statistical analysis of the water supply system failure seasonality.; Using the selected statistical approaches for the analysis of water pipelines failure rate indexes λ.; Seasonal course of the water pipelines failure events can be relatively easy to predict by using the Colwell indexes.; Not clear impact of a given period of the year on water supply system failures was found.;

Keywords

• failure rate index λ
• seasonality
• statistical analysis
• trend
• water pipelines
• water supply system