جستجوی مقالات مرتبط با کلیدواژه « Nahavand Plain » در نشریات گروه « آب و خاک »

In this research, support vector machine (SVM) and artificial neural network (ANN) were used to simulate the monthly Groundwater level of Nahavand plain located in Hamedan province. Twenty years data (1997-2017) were used by engaging Matlab software. From these data, 14 years were used for training, 3 years for calibration and finally 3 years used for model validation. The statistical comparison of the results was also attempted with the aid of correlation coefficient (r) and standard error (SE). Four observation wells were used along with the variables of Groundwater level, precipitation, evaporation and temperature to simulate the Groundwater level. The highest accuracy among these two models is SVM model, which has SE = 0.11 in the training mode and 0.03 in the test mode. Also, the correlation coefficient in the test mode is 98%. Considering the appropriate accuracy of SVM method in simulating the groundwater level, the results indicate that, the RBF kernel function, with a variance of 6523 and a gamma of 527.23 for the optimal mode. The results of this study showed by using the SVM approach is more realistic in simulation of groundwater level and evaluation of the input parameters. In addition this could help in reducing the number of input parameters as well as can show appropriate accuracy for the simulation.

Groundwater aquifers is the main   source of water supply required by the country in recent years and the use of simulation models for proper aquifer management is essential. In this study, the water table variations in the Nahavand aquifer were simulated with a GMS (computer based model) in a steady state for the month of October and unsteady state for 9 years from October 2006 to September 2015. To calibrate the model, the field measured data from piezometric wells were used from 2015 to 2016. The estimation of hydrodynamic parameters of the aquifer using PEST package was carried out with the adaptation of the depth to water table by implementation to model. The results of the model include prediction of water table variations in Nahavand Plain   by considering with or without three management scenarios which shows reducing at the time of wells Operation     in the next 10 years. The results showed that lowering the withdrawal from the wells by less than 10% could not stop the downward trend of the aquifer potentials. The reduction of 30% of the utilized may resulted in the establishment of fixed conditions and a reduction of more than that to a value of 50% capable of compensating for the deficit in a long-term period. Finally, the average depth of the groundwater level was determined by the Theisen method during the study period for each year, and the zoning and groundwater level map was processed by GIS software, It’s found that, groundwater level has been reduced in different areas of the plain from 1.5 to 13 m and the average of the total aquifer was 5.7 m declination during the study period.