Quantitative groundwater prediction and modeling using MODFLOW model (Case study: Herat City-Afghanistan)

Abstract

Herat city is located in the southwest of Afghanistan and is considered a semi-arid region, and the average rainfall in this city is 200 mm per year. The direction of groundwater flow is also from the northeast to the southwest of the city. According to the obtained information, the water level has dropped significantly in this area in recent years. In order to more accurately understand the aquifer from a hydrogeological point of view and optimally utilize groundwater resources, a mathematical model of groundwater in Herat City has been prepared using the MODFLOW model.

Initially, the required information including meteorological, hydrological, hydrogeological and other field and required information was collected and then a conceptual groundwater model was prepared using the available information. At this stage, information regarding alluvial thickness, boundary conditions, balance information, etc. was prepared using GIS software and entered into the mathematical model. This model was implemented for the water year in 1402-1403 with 12 time steps. After the implementation and calibration of the model, the results of the computational load and observation load in stable and unstable conditions indicate a drop of approximately 3 meters in the groundwater of this city in the next 5 years.