Flood Control Operations Based on the Theory of Variable Fuzzy Sets

Abstract

Flood control decisions are often involved with quantitative and qualitative criteria. In this paper, a decision model is presented for flood control operations based on the theory of variable fuzzy sets. Using dual comparison, two models computing relative membership grades with qualitative and quantitative criteria are established, respectively. A method integrating subjective preference and iterative weights is proposed for weight-assessment. First, an initial solution of criteria weights is obtained by using proposed fuzzy optimal iteration model. Then, according to their knowledge related to real time flood operations, operators may modify the initial weights if necessary. When the relative membership grades of alternatives belonging to all rankings are fixed by using multi-criterion variable fuzzy model proposed, the decision alternative is chosen according to the ranking characteristic value computed using a defuzzification equation. The case study of Fengman Reservoir flood operation (in China) is provided to illustrate the application of the proposed method. With the incorporation of operator's knowledge related to flood operations, the proposed model is flexible and practical.

Suitability assessment of deep groundwater for drinking, irrigation and industrial purposes in Jiaozuo City, Henan Province, north China

“…VFS, developed by Chen [23], has proven to be a useful tool in dealing with vagueness or fuzziness information. It is widely employed to assess multicriteria decision making problems [24][25][26], which consist of probability theory and fuzzy sets. The priority criterion matrix I 1 , the certain interval matrix I 2 , the point value matrix M, and the optimal relative membership grade matrix U are the most important concepts in VFS.…”

“…The priority criterion matrix I 1 , the certain interval matrix I 2 , the point value matrix M, and the optimal relative membership grade matrix U are the most important concepts in VFS. For the length of this article, the calculation process is omitted; details on some of this method and their applications have been described by previous articles [23][24][25][26].…”

Fuzzy Logic for Rainfall-Runoff Modelling Considering Soil Moisture

“…Fuzzy logic has been employed in water resources engineering area such as reservoir operation modelling (Panigrahi and Mujumdar 2000), sediment transport prediction (Tayfur et al 2003), dispersion coefficient prediction (Tayfur 2006), rainfall-runoff modelling (Tayfur and Singh 2006), mean and bankful discharge prediction (Tayfur and Singh 2011), flood control operations (Wang et al 2011), reservoir operating rule development (Kumar et al 2013), hydraulic conductivity estimation (Tayfur et al 2014), among many.…”

Sensitivity Analysis of Mountain Flash Flood Risk: Case of Licheng County in China

“…Owing to the impact of each index on flash flood risk with a linear or nonlinear relationship which has randomness and fuzziness, variable fuzzy method (VFM) is adopted to evaluate flash flood risk. VFM, developed by Chen Shouyu in 2005 [26][27], is an effective evaluation method for fuzzy system with linear or nonlinear relationship, and is widely used in water resources evaluation [27][28], water environment evaluation [29][30][31], flood control operations [32], land suitability evaluation [37], water quality assessment [38][39][40] and flood risk assessment [41]. The purpose of of this study is to find out the sensitivity factors for flash flood risk evaluation and determine the priorities of flash flood prevention and control of numerous small watersheds in hilly regions.…”