Assessing the earth dams’ effect on the groundwater of its location case study: Kord-Oliya dam

Abstract

The main objective of the construction of the Kord-Oliya earth dam is to reserve surplus water for consumption and artificial recharge in the area. The effect of such dams on the basin is to alter the hydrological regime of its adjacent areas to somehow prevent drought. By considering the existence of such dams and the costs of their construction, operation, and maintenance, it is necessary to study their effect on surrounding groundwater. The objective of this study is to combine a geotechnical model for the subject earth dam through SEEP 3D software and its output in hydrogeological model through GMS software in a 3D mode for surface and groundwater management in a simultaneous manner. It is necessary to estimate the groundwater level of the area, to determine the hydrogeological and geotechnical conditions of the aquifer through mathematical models for optimal exploitation of the Karvan Plain. Excessive water harvesting for agriculture consumption from the Karvan aquifer has been and is on an increase which has led to a decrease in groundwater level in the area and introduced many environmental risks. This modeling is calibrated and validated for 121 months on this aquifer in both the steady and unsteady states in two scenarios with and without this earth dam. The obtained results indicate that existence of this dam does not increase the groundwater level in a gradual manner in the area in the consecutive years, while the mean groundwater level is on an increase by 14 m. By considering scenario one, the total volume of alluvial aquifer reserves increase 83.4 Mm3.