Evaluating Risk of Multi-Segment Pipes for Prioritizing Pipe Rehabilitation

The evaluation of risk at the individual pipe level can play an important role in the rehabilitation planning of water distribution systems. Yet pipe segments are generally arbitrarily defined in GIS or other databases and individual sections rarely make suitable rehabilitation entities on their own. In reality, groups of pipes need to be considered together for viable projects. The ability to group neighboring segments either prior to or subsequent to risk analysis has the potential to facilitate analysis and/or the actual practical rehabilitation. This paper looks briefly at the assessment of risk at pipe level before discussing how individual segments of pipe can be grouped into meaningful entities before or after such analysis. The objective is to maximize the benefit, in terms of risk avoidance, whilst minimizing the number of multi-segment pipes proposed for rehabilitation. Data from case studies are used to illustrate any advantages or shortcomings of the methods proposed.