Ahmad Tahershamsi - Associate Professor, Department of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
Atabak Feizi - Assistant Professor, Faculty of engineering, Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
Siavash Molaei - Sc. student, Water Engineering and Hydraulic Structures, Department of Civil and Environmental Engineering, Amirkabir University ofTechnology, Tehran, Iran

Simulation of groundwater flow by mathematical model can be used for developing aquifer balance element analysisscenarios, explaining conditions of droughts, definition of prohibitive extraction policies and analyzing the qualitativemodels. In this study, the development of a quantitative model in terms of the main parameters affecting on the watersurface changes has been performed for the Ardebil plain (located in NW of Iran). Accordingly, a comprehensiveprocessing of raw data sets has been carried-out by means of MODFLOW mathematical model. Also to simulate thegroundwater surface changes in the mentioned plain, the geo-statistical method has been used. Results indicate that themathematical model used in the aquifer balance simulation for the Ardebil plain has approximately 2% relative normalroot-mean-square error (NRMSE). This small NRSMSE confirms the model accuracy for the Ardebil plain using thecalibration data. Moreover, comparing the results of this method and the ones obtained by mathematical model performedby examining some error criteria like RMSE, Mean, ASE and MS, it is found that the accuracy of the mathematical modelis higher than the geostatistical method and the main reason for this is the distribution of uncertainty in a few availablepiezometric points in the geostatistical method.

Ardabil Plain Aquifer; Aquifer Balance; Geostatistics; MODFLOW