Aquifer transmissivity estimation using different interpolation methods (Case study: Damaneh-Daran Aquifer)

Aquifer transmissivity is one of the important parameters for groundwater quantitative and qualitative studies and modeling. Due to the limited number of pumping tests or the ambiguity in the accuracy of the measured values in some places, it is necessary to estimate the transmissibility value using the available information. In this research, the values of this parameter are determined using different interpolation methods including Inverse Distance Weighted (IDW), ordinary kriging (by use of circular, exponential, Gaussian and spherical variogram), universal kriging (include linear and quadratic trend), spline (regularized and tension) and trend (include linear and logistic regression) Therefore, here, the transmissivity coefficient of the Damaneh-Daran aquifer, as a case study, is determined and the results are presented and compared. Comparison of the results shows that performing interpolation with Regularized Spline leads to the lowest accuracy and using Ordinary Kriging method in power mode leads to the highest computational accuracy (with 20.11% relative error). However, this method is not effective for interpolating points located in the boundary areas of the study state. In contrast, the IDW method with a maximum of 21.36% relative error can be used for interpolation in all parts of the region. Finally, in order to evaluate the performance of this method, the Damaneh-Daran aquifer is simulated based on the results of IDW method as initial values and using GMS software. By comparing the results obtained from calibration of the aquifer with values obtained from interpolation, the maximum relative error value is 22.22% and the average relative error at the aquifer level is 15.69%. Also, with a significant reduction in the number of iterations in the calibration phase of the model, the computational cost is significantly reduced.