Studying Groundwater Flows by Using Mathematical Models in Order to Optimize the Hydraulic Parameters (Case study: Kabudarahang plain_ Hamadan)

The indeterminacy of data, specifically for the measure K, water pumping rate, rivers feeding, transmissivity, and the storage coefficient seem to be the most important factors of error in the underground water flows model. On the other hand, the heterogeneity and anisotropicity of aquifers in the cells is another factor of causing error in the process of calibration. Kabudarahang plain constitutes one of the study fields of the Gharechay river area, covering an area of 3448 2 km , lying in the north of Hamadan Province, and having connections with Ghazvin and Zanjan plain in the north, Qahavand and Bahar plain in the south, Razan in the east, and the area of study of GolTaPpeh-Zarrin Abad in the west. The under-study area, covering 286 square km, is located in Hamadan province. Having chosen the proper software package MODFLOW/PM, we started to attempt to provide a concept model and simulate the aquifer. Among the foregoing elements, K had the most striking role in increasing errors because it was extracted from alluvium thickness (saturation zone thickness) and transmissivity maps. Results showed that the highest revision was made on the hydraulic conductivity rate and the lowest was made about the bedrock. Implemented calibration has also caused remarkable improvements in the foregoing condition and, afterwards, the simulated model of the water flow has been used for the prediction or optimization of the underground water reservoirs of the aquifer system.