Fault tree analysis for integrated and probabilistic risk analysis of drinking water systems
Journal article, 2009

Drinking water systems are vulnerable and subject to a wide range of risks. To avoid sub-optimisation of risk-reduction options, risk analyses need to include the entire drinking water system, from source to tap. Such an integrated approach demands tools that are able to model interactions between different events. Fault tree analysis is a risk estimation tool with the ability to model interactions between events. Using fault tree analysis on an integrated level, a probabilistic risk analysis of a large drinking water system in Sweden was carried out. The primary aims of the study were: (1) to develop a method for integrated and probabilistic risk analysis of entire drinking water systems; and (2) to evaluate the applicability of Customer Minutes Lost (CML) as a measure of risk. The analysis included situations where no water is delivered to the consumer (quantity failure) and situations where water is delivered but does not comply with water quality standards (quality failure). Hard data as well as expert judgements were used to estimate probabilities of events and uncertainties in the estimates. The calculations were performed using Monte Carlo simulations. CML is shown to be a useful measure of risks associated with drinking water systems. The method presented provides information on risk levels, probabilities of failure, failure rates and downtimes of the system. This information is available for the entire system as well as its different sub-systems. Furthermore, the method enables comparison of the results with performance targets and acceptable levels of risk. The method thus facilitates integrated risk analysis and consequently helps decision-makers to minimise sub-optimisation of risk-reduction options.

Drinking water system

Probabilistic

Risk analysis

Fault tree

Customer Minutes Lost

Uncertainties

Integrated

Author

Andreas Lindhe

Chalmers, Civil and Environmental Engineering, Geology and Geotechnics

DRICKS - Framework programme for drinking water research at Chalmers

Lars Rosen

Chalmers, Civil and Environmental Engineering, Geology and Geotechnics

FRIST competence centre

DRICKS - Framework programme for drinking water research at Chalmers

Tommy Norberg

University of Gothenburg

Chalmers, Mathematical Sciences, Mathematical Statistics

FRIST competence centre

Olof Bergstedt

Chalmers, Civil and Environmental Engineering, Water Environment Technology

Water Research

0043-1354 (ISSN) 1879-2448 (eISSN)

Vol. 43 6 1641-1653

Areas of Advance

Building Futures (2010-2018)

Subject Categories

Civil Engineering

Oceanography, Hydrology, Water Resources

Probability Theory and Statistics

DOI

10.1016/j.watres.2008.12.034

More information

Created

10/7/2017