Dynamic decision making for dam-break emergency management – Part 1: Theoretical framework

Abstract

Abstract. An evacuation decision for dam breaks is a very serious issue. A late decision may lead to loss of lives and properties, but a very early evacuation will incur unnecessary expenses. This paper presents a risk-based framework of dynamic decision making for dam-break emergency management (DYDEM). The dam-break emergency management in both time scale and space scale is introduced first to define the dynamic decision problem. The probability of dam failure is taken as a stochastic process and estimated using a time-series analysis method. The flood consequences are taken as functions of warning time and evaluated with a human risk analysis model (HURAM) based on Bayesian networks. A decision criterion is suggested to decide whether to evacuate the population at risk (PAR) or to delay the decision. The optimum time for evacuating the PAR is obtained by minimizing the expected total loss, which integrates the time-related probabilities and flood consequences. When a delayed decision is chosen, the decision making can be updated with available new information. A specific dam-break case study is presented in a companion paper to illustrate the application of this framework to complex dam-breaching problems.

Dynamic decision making for dam-break emergency management – Part 2: Application to Tangjiashan landslide dam failure

“…Let us assume that the dam-break flood arrives at t f and the warning is issued at t w . The flood consequences with any t w in this range can be obtained with the method presented in the companion paper (Peng and Zhang, 2013). For example, assuming t w is at 00:00 on 17 May, then t w = t 72 .…”

“…DYDEM is a dynamic decision framework for dam-break emergency management that is introduced in the companion paper (Peng and Zhang, 2013). In this framework, the probability of dam failure is taken as a stochastic process and estimated using a time-series analysis method.…”

“…Based on conservation of mass as introduced in the companion paper (Peng and Zhang, 2013), the reservoir volume at time t, V t , is given by…”

“…The flood consequences are closely related to the evacuation rate, sheltering rate and loss of life, which are estimated using a human risk analysis model (HURAM) based on Bayesian networks (Peng and Zhang, 2012a, b). The methodology of evaluating flood consequences, which is coded in Microsoft Excel, has been introduced in the companion paper (Peng and Zhang, 2013). A human life is monetized according to macro-economic contributions.…”

“…A dynamic decision-making framework for dam-break emergency management (DYDEM) under uncertainty has been presented in the companion paper (Peng and Zhang, 2013). In this paper, the DYDEM is applied to the dynamic decision analysis for the Tangjiashan landslide dam failure.…”