Identification of critical pipes in a drinking water distribution system

Abstract

The aim of this master thesis is to identify the most critical pipes in a drinking water distribution system through hydraulic modelling. The criticality of a pipe will be based on the consequences of pipe breakage including the affect on the supply of valuable users. Reliability will be seen as the ability to supply the quantitative demand to the households and valuable users at any time and to identify the criticality of a pipe, the pipe´s contribution to the system reliability has been evaluated. The contribution are estimated by evaluating the results from hydraulic simulation of the drinking water system, without the investigated pipe. Four indices, demand, affected users, time and valuable user index as well as a gathered criticality index are used to estimate the reliability of a drinking water system. To give more substance of the identification of critical pipes the reliability requirements of a drinking water distribution system could be further evolved. When determining the criticality of the pipes in the system, one key aspect is how pipes with different patterns should be compared between each other. Pressure driven and demand driven approach gave the same results for the majority of the pipes and a risk-based approach including probabilities would give a more in depth analysis of the criticality.