Vulnerability, Risk, and Mitigation Assessment of Water Distribution Systems for Insufficient Fire Flows

Water distributions systems must reliably supply water for fire-fighting needs as well as everyday demands but are vulnerable to a range of failure types that can compromise both functions. A methodology is presented integrating failure probability, risk analysis, and optimization of risk that can be used to assess system vulnerabilities and potential mitigation actions. To demonstrate multiple failure mode analysis, three failure types are included: accidental failure due to soil-pipe interaction, accidental failure due to a seismic event, and malevolent attack. A risk-optimization algorithm is implemented using dynamic programming to identify the failure scenarios having the greatest consequences and probability rather than focusing on just one aspect of vulnerability. Finally, potential mitigation strategies are assessed in a benefit-cost-risk reduction analysis. The methodology is intended as a practicable means for infrastructure managers to assess and address system vulnerabilities in a realistic and cost-effective manner.