Estimation of parameters in groundwater modelling by modified Clonalg

Abstract

The purpose of this study was to improve the optimization model for predicting more parameters in more difficult conditions (more grid cell numbers and high time interval numbers) than other studies in groundwater flow modelling. Also, the model needs fewer observation numbers for estimating parameters than other studies. In the present study, an optimization model based on model calibration was developed to estimate simultaneously four groundwater flow parameters – hydraulic conductivity, transmissivity, storage coefficient and leakance. The modified clonal selection algorithm, a class of artificial immune systems, was used as a heuristic optimization method. In order to simulate the groundwater flow, MODFLOW was used in conjunction with the model in MATLAB. The input files for MODFLOW were obtained by GMS groundwater simulator. The model was applied to two different hypothetical groundwater systems (two- and three-dimensional) under transient conditions to evaluate its performance. The results showed that the model was feasible for groundwater flow modelling and it could determine the groundwater flow parameters successfully with less observations and more grid cell numbers than the other studies. HIGHLIGHTS The optimization model was improved for determining groundwater model parameters.; The model can estimate more parameters in more difficult conditions (more grid cell numbers and high time interval numbers) than other studies.; The model needs to less observation numbers for estimating parameters than other studies.;

Keywords

• groundwater modelling
• heuristic optimization
• model calibration
• parameter estimation