In recent years, there is more interest in water sources availability, including groundwater due to an increase in demand for water because of the increasing population in the world, and the water recedes due to climate change also. Therefore, the study of groundwater has required more attention. The aim of the present study is to establish a MODFLOW model in the groundwater modeling system software to simulate the movement of groundwater in the Turssaq alluvial fan which is located in the Qazaniyah city, east of Diyala Governorate. The solid model was used to define the aquifer in the study area. Using the GIS software, mapping and preparing the data needed to create a conceptual model were carried out. The data of the wells were used to create and define the aquifer, then a three-dimensional model was created. Measuring the water table for some wells were simultaneously monitored to determine the hydraulic conductivity values of the aquifer through the (PEST) package provided by the software. The hydraulic conductivity value of the main layer was 18 m/d. Then several readings of observation wells were recorded for the period extended from 1/Nov/2018 to 22/May/2019 for the calibration process in the unsteady situation and to determine the coefficient of storage. The value of the storage coefficient was defined as 0.001. Several scenarios were conducted for the study area to find the best distance between the wells. Three distances were tested, 500, 1000 and 1500 m. The operating periods were 6, 12 and 18 (hours/day). Results obtained from the model show that the best distance between the wells is 1000 meters with a maximum operating rate of 12 hours/day. The maximum discharge with the lowest distance and the lowest drawdown of the groundwater table are considered.
