SINGLE-BOREHOLE DILUTION TESTS IN A LIMESTONE AQUIFER AND PARAMETER ESTIMATION USING SWARM INTELLIGENCE

Abstract

 In this study, we conducted single-borehole dilution tests in a limestone site to estimate the parameters such as the hydraulic conductivity, pore velocity and dispersion coefficients. Two analytical solutions associated with the variation of concentration were linked with observed breakthrough curves to identify the parameters. Swarm intelligence techniques including particle swarm optimization (PSO) and cuckoo search algorithm (CKA) were applied as an inverse approach and demonstrated these efficient ability to solve parameter estimation problem. We found that in the site hydraulic conductivity decreases with the elevation, and estimated parameters varied according to an individual observation hole. Also, subsequent solute transport simulations were in reasonable agreement with observed transitional concentration data. It was revealed that the slope of the breakthrough curves was dependent on the well diameter in the site of concern.