Delineation of wellhead protection area based on the analytical elements method (AEM) – a case study with comparative research

The delineation of protection zones for groundwater intakes is a difficult task resulting from the significant variability of regional and local environmental conditions. Different methods are used, both simple (analytical or graphic), giving estimated results, and the most reliable, but also the most time-consuming ones, based on numerical groundwater flow models. An alternative method for the delineation of protection zones is the analytical elements method (AEM), which gives solutions like those obtained using FDM/FEM modelling methods with a relatively low degree of complexity. The estimated ranges of protection zones obtained with the use of four methods are presented for the selected test area (groundwater intake around Olesno). Results obtained with the use of the FDM model were taken as reference and CFR and SimpleWHPA were used as simplified methods. Comparative studies indicate that the results obtained by the CFR method differ significantly from the results of other methods, and their reliability is low. The results of the SimpleWHPA method are satisfactory, given the relative simplicity of the method. On the other hand, the results obtained with the AEM are close to the results obtained with the FDM treated as a reference. Considering that AEM is less time-consuming than FDM (which requires the most effort for proper model preparation), the use of AEM in the practice of protection zone delineation seems to be an interesting alternative.