A field demonstration of the entropy-weighted fuzzy DRASTIC method for groundwater vulnerability assessment

Abstract

., 2012. A field demonstration of the entropy-weighted fuzzy DRASTIC method for groundwater vulnerability assessment. Hydrological Sciences Journal, 57 (7), 1420-1432.Abstract Groundwater vulnerability assessment based on the DRASTIC index has been widely used since the 1980s to map potential risks of groundwater contamination. However, its applicability and usefulness are affected by two uncertain and subjective factors. One is the discretization of continuous input variables and the other is the assignment of different weights to the index variables. In this study, an entropy-weighted fuzzy-optimization approach was developed to augment and improve the classic DRASTIC method by reducing the uncertainties associated with variable discretization and weight assignment. The modified DRASTIC method was applied to a study site in Shandong, north China. The entropy-weighted fuzzy-optimization approach is shown to provide a more rigorous delineation of the relative vulnerability distribution. Meanwhile, the new approach does not require the use of more parameters. The results suggest that this approach significantly improves and enhances the ability of the classic DRASTIC method in a more systematic and rigorous way.Key words groundwater vulnerability; DRASTIC index; entropy-weighted fuzzy optimization; sensitivity analysis Une démonstration de terrain de la méthode DRASTIC floue pondérée par l'entropie pour l'évaluation de la vulnérabilité des eaux souterraines Résumé L'évaluation de la vulnérabilité des eaux souterraines sur la base de l'indice DRASTIC a été largement utilisée depuis les années 1980 pour la cartographie des risques potentiels de pollution des eaux souterraines. Son applicabilité et son utilité sont cependant affectées par les deux facteurs que sont l'incertitude et la subjectivité. Il faut d'abord discrétiser les variables d'entrée continues, puis attribuer des poids aux variables de l'indice. Dans cette étude, nous avons adopté une approche d'optimisation floue pondérée par l'entropie, afin d'élargir et d'améliorer la méthode DRASTIC classique en réduisant les incertitudes liées à la discrétisation des variables et à l'attribution des poids. La méthode DRASTIC modifiée a été appliquée à un site d'étude dans le Shandong, au Nord de la Chine. L'approche d'optimisation floue pondérée par l'entropie s'est révélée fournir une définition plus rigoureuse de la distribution relative de vulnérabilité. En même temps, la nouvelle approche ne nécessite pas d'utiliser davantage de paramètres. Les résultats suggèrent que cette approche améliore significativement et de façon systématique et rigoureuse le potentiel de la méthode DRASTIC classique.

GALDIT Modification for Seasonal Seawater Intrusion Mapping Using Multi Criteria Decision Making Methods

“…Combined, GALDIT modified using entropy and the Wilcoxon test provided a suitable vulnerability map. Yu et al [24] also used entropy theory to modify the weights of DASTIC parameters based on the level of variance of parameters and the relative importance of each parameter. Agossou et al [30] determined the weights of DRASTIC parameters based on entropy theory.…”

“…H represents the expected value of all the signals' content and C is a coefficient. The entropy approach used in this study is described in Yu et al [24]. The approach is applied in three steps.…”

“…Step 3: Modified weight This phase consists of altering the relative weight assigned by GALDIT to define a new weight. The variance in weight specification in the classic GALDIT and the variance in parameter ratings are considered in the estimation of new weight (Yu et al [24]). The new modified weight for each parameter j is the product of the relative variation in the ratings and the GALDIT classic weight.…”

Assessment of factors affecting the intrinsic vulnerability of groundwater rated by the mean residence time estimation method

“…Al though the results ob tained with the in dex meth ods are qual i ta tive, they are still com monly used world wide, es pe cially via the very ef fec tive DRASTIC method (e.g., Krogulec, 2006;Ró¿kowski, 2007;Saidi et al, 2011Saidi et al, , 2017Khemiri et al, 2013;Krogulec and Trzeciak, 2016). This method has been im proved and ad justed to com plex hydrogeological con di tions (Witkowski et al, 2003;Yu et al, 2012;Jiménez-Ma drid et al, 2013;Hernández-Espriú et al, 2014;Kazakis and Voudouris, 2015;Bonfanti et al, 2016;He et al, 2018). Com bined meth ods gen er at ing a qual i ta tive result are also used (Gemitzi et al, 2006;Civita, 2010).…”

A novel method of sensitivity analysis testing by applying the DRASTIC and fuzzy optimization methods to assess groundwater vulnerability to pollution: the case of the Senegal River basin in Mali

“…So to improve and adapt the DRASTIC model to the particularity of the study area, it is better to modify the classical model or combine it with other developed models to get better results. Many studies proposed methods which combined DRASTIC and other methods (Yu et al, 2012;Dhar and Patil, 2012;Fernando et al, 2013;Madhumita et al, 2016). Leone et al (2009), Luis et al (2009) and Neshat et al (2015a, b) all proposed modified models to assess groundwater vulnerability to pollution.…”