Fate/transport modeling using fuzzy numbers

Sensitivity analysis of groundwater transport modeling platforms traditionally considers different levels of parametric uncertainty. The true uncertainty associated with any hydrogeologic parameter should be recognized to be a combination of two distinct types of uncertainty the vagueness of a parameter and the statistical randomness of the parameter. In the physical hydrogeological world the dominant type of uncertainty results from the inherent vagueness of parametric values, not the randomness of the values. Vagueness arises from the difficulty in making clear or sharp distinctions as to exact parametric values, whereas randomness is associated with the frequency of occurrence. This paper describes a fuzzy mathematical methodology used to model chloride ion transport in a shallow unconfined aquifer underlying an abandoned sand quarry in Borden, Ontario. The results of the fuzzy modeling indicate fuzzy mathematical methods can provide a useful methodology to address the uncertainty associated with vaguely defined parameters.