Assess the risk of extreme floods : case study : Houston, Texas

The catastrophic flooding caused by the Hurricane Harvey, ranked as the third 500-year floods in three years in Houston Area, has inflicted nearly $200 billion in damage. The traditional Hydro-Economical Model of a specific stream station along Buffalo Bayou in Houston area is established following the standard of practice in the report. A different perspective of non-informative prior sample space from the DET theory is built as well based on the preference between two alternatives to evaluate the risks in decision analysis. The comparison between the recommendations from the DET theory and from the statistical extrapolation of standard of practice on selecting the first-floor elevation of one building is presented. The extrapolation method tends to choose a higher first-floor elevation no matter what the shape of the utility function is, while the preferred value from the DET is sensitive to the utility function. When the cost of implementation is extreme high for higher elevations, the extrapolation method recommends a lower first-floor elevation while the DET prefers a higher elevation. The DET framework takes the shape of utility function as well as the decision faced with extreme event into consideration, and turns out to be a rational way to analyze the flood risks.