Iterative Analysis: Bounded Leaky Artesian Aquifer

Application of the leaky artesian well function (Hantush and Jacob, 1955) to the analysis of aquifer-test data may be difficult if there are boundaries close enough for their effects to obscure those of leakage. If available information is adequate to establish boundary locations with reasonable accuracy, and if transmissibility and storage coefficient can be determined from early drawdown data, the leakage factor, B, may be determined by iterative adjustment of an initial rough estimate until observed and calculated drawdowns match within some specified range of accuracy. An algorithm for iterative adjustment is developed and a method of improving its efficiency discussed. Formulas are presented for generalized image-well positions for a strip aquifer and all results combined and applied to digital-computer analysis of drawdown data for a buried preglacial bedrock-valley aquifer near Stettler, Alberta. Three computed values of B agreed closely and calculated drawdowns based on an average B matched observed drawdowns satisfactorily.