Comprehensive review of structural deterioration of water mains: statistical models

This paper provides a comprehensive (although not exhaustive) overview of a large body of work carried out in the last twenty years to quantify the structural deterioration of water mains by analysing historical performance data. The physical mechanisms that lead to pipe failure often require data that are not readily available and are costly to obtain. Thus, physical models may currently be justified only for major transmission water mains, where the cost of failure is significant, whereas statistical models, which can be applied with various levels of input data, are useful for distribution water mains. The statistical methods are classified into two classes, deterministic and probabilistic models. Sub classes are probabilistic multi-variate and probabilistic single-variate group processing models. The review provides descriptions of the various models including their governing equations, as well as critiques, comparisons and identification of the types of data that are required for implementation. In some cases, a brief description of the methodology is provided where a decision support system was developed based on a specific statistical model. A companion paper “Comprehensive Review of Structural Deterioration of Water Mains: Physical Models” helps to complete the picture of the work that has been done on the subject of water main deterioration and failure.