A top specified boundary layer (TSBL) approximation approach for the simulation of groundwater contamination processes

This paper presents improvements in the “classical boundary layer” (CBL) approximation method to obtain simple but robust initial characterization of aquifer contamination processes. Contaminants are considered to penetrate into the groundwater through the free surface of the aquifer. The improved method developed in this study is termed the “top specified boundary layer” (TSBL) approach. It involves the specification of the contaminant concentration at the top of the contaminated “region of interest” (ROI), which is simulated as a boundary layer. The TSBL modification significantly improves the ability of the boundary layer method to predict the development of concentration profiles over both space and time. The TSBL method can be useful for the simulation of cases in which the contaminant concentration is prescribed at the aquiferʹs free surface as well as for cases in which the contaminant mass flux is prescribed at the surface.