Post‐flood assessment of emergency evacuation policies in the Red River basin, Southern Manitoba

Abstract

A discrete choice experiment (DCE) was used as a part of a post‐flood survey among the residents of four small urban communities on the Red River ‐ Emerson, Morris, Ste. Agathe, and St. Adolphe ‐ to assess their preferences for emergency evacuation policies. The respondents were asked to choose repeatedly among three hypothetical evacuation policies described in terms of (a) the type of evacuation (mandatory, voluntary, no evacuation), (b) notification time for evacuation (1, 2, 4 days), (c) post‐evacuation flood relief (75%, 80% current, 90%), and (d) an overall evaluation of the risk of hazardous flooding, i.e. chances of over‐dike flooding or breaching through dikes (99%, 75%, and 50%). The survey results indicated that, despite significant differences between Ste. Agathe and other communities in the magnitude of impact of the 1997 flood, overall, a voluntary evacuation seemed to be preferred at the 50 percent risk of hazardous flooding; whereas the preference for a mandatory evacuation was related to a 99 percent risk. A notification time of 2 days for evacuation was preferred over that of 1 day but the preference for 2 days was not statistically different from that of 4 days. In both types of evacuation a 10 percent increase in the amount of flood relief was preferred over the current amount of 80 percent and the marginal utility of a 5 percent decrease was nearly equivalent to the suggested 10 percent increase. Because of such ability of the DCE to assess tradeoffs of alternative choices/policies, the paper suggests further applications of the model for eliciting floodplain residents' preferences for various flood management issues. Dans le cadre d'une enquête effectuée auprès des résidents de quatre petites communautés urbaines ‐ Emerson, Morris, Ste‐Agathe et St‐Adolphe ‐ à la suite des inondations de la rivière Rouge, les préférences du public quant à la politique à suivre en cas d'évacuation ont étéétudiées. L'évaluation a été menée à partir d'un modèle à choix discret. Les personnes interrogées devaient choisir entre trois hypothèses d'évacuation, hypothèses établies sur les bases suivantes: a) le type d'évacuation (obligatoire; volontaire; non‐évacuation); b) le délai accordé avant l'évacuation (1, 2 ou 4 jours); c) les secours procurés à la suite de l'évacuation (75%, les 80% actuels, 90%); et, d) une évaluation d'ensemble des dangers d'inondation, par exemple, les possibilités qu'une digue soit submergée, ou que les digues rompent par endroits (99%, 75% et 50%). Les résultats de l'enquête montrent que, dans l'ensemble, malgré une différence significative dans l'importance de l'impact de l'inondation de 1997 à Sainte‐Agathe et dans les autres communautés, le choix d'une évacuation volontaire était préféré quand ne se présentait qu'une possibilité d'inondation de 50 pour cent; la préférence pour une évacuation obligatoire n'étant indiquée que dans le cas de 99 pour cent de risques d'inondation. Un avertissement avant évacuation de 2 plutôt qu'l jour était préféré par les personnes interrogées, mais, s...

A review on travel behaviour modelling in dynamic traffic simulation models for evacuations

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Amateur decision-making in avalanche terrain with and without a decision aid: a stated choice survey

“…While the stated preference technique of DCE is commonly used to elicit personal opinions or choice preferences for the purpose of calculating market shares of a future product (Louviere et al 2000), examining policy support (Rasid et al 2000;Arnberger and Haider 2007) or estimating the consumer surplus for a non-market public good (Adamowicz et al 1998;Tsuge et al 2005), the focus of the present study is the assessment of the decisionmaking process itself. Studies examining decision-making commonly use normative models (see, e.g.…”

Community strategies to improve flood risk communication in the Red River Basin, Manitoba, Canada

“…The uncertainty of the nature of the ramifications of larger floods might lead to elevated anxieties and amplification of risk perceptions. However, because of the residents' keen desire to combat the floods themselves, this type of social amplifica tion of risks might not necessarily lead to support for mandatory flood evacuation (Rasid, Haider and Hunt, 2000;Rashid, Haider and McNeil, 2007). On the contrary, based on experience of the 1997 flood, it was postulated that many floodmarooned residents might be determined to defy mandatory evacuation by undertaking pri vate flood alleviation measures to protect their personal property.…”