Application of a Flood Risk Assessment Model Combining Analytic
Hierarchy Process Modified by Trapezoidal Fuzzy Number and Variable
Fuzzy Set Theory: A Case Study in Zhejiang Province, China.
Abstract
Abstract: The scientific evaluation of regional flood risk is
particularly important for flood management. Past studies build a
hierarchy evaluation index system with two factors and ten sub-factors
to assess flood hazard risk, each factor contains five sub-factors. The
weights of the sub-factors in their respective evaluation systems are
(0.065, 0.129, 0.210, 0.215, 0.378) and (0.399, 0.152, 0.155, 0.180,
0.109) respectively, from expert scoring results optimized by Analytic
Hierarchy Process (AHP) modified by Trapezoidal Fuzzy Number (TFN).
Variable Fuzzy Set Theory (VFST) is adopted to calculate the risk values
of the two factors, the weighted average of two factors risk values is
used as flood disaster risk value. Based on above steps, a flood
disaster evaluation model is established and applied to evaluate
regional flood risks in Zhejiang Province. Extremely low risk, low risk,
moderate risk, high risk, extremely high risk areas are 51017 km2,10090
km2,10112 km2,13428 km2 and 19153 km2, respectively occupy with 49.15%,
9.72%, 9.74%, 12.94%, and 18.45% of study region. TFN-modified AHP
calculates the weights of sub-factors, considering the subjective
cognition of experts and the objective response of factors, which makes
the results more representative and scientific. Application of VFST
decreases the randomness and uncertainty of flood risk assessment, which
improves the stability of evaluation process and reliability of
evaluation results. Meanwhile, 30×30m basic evaluation unit adopted in
this study accurately and objectively represent the spatial distribution
of flood hazard in Zhejiang Province, China. The evaluation results of
the model are validated to be consistent with the actual situation of
flood disaster.