Spatial and Temporal Variation of Groundwater Flow in Southeastern bank of Urmia Lake

In recent years, Urmia Lake has dried up and its salinity has increased significantly. There are various reasons for this phenomenon. There is even a difference in the manner and rate of direct or indirect role of groundwater compared to surface water. Therefore, in this study, in order to identify the interaction of groundwater and surface water in the southeastern coast of the lake as the most important input to the surface waters of the lake, the temporal and spatial variations of groundwater flow were investigated. This study was carried out using the groundwater level map in May 2008, 2013 and 2016, as well as the groundwater transmissivity map and the rate of groundwater inflow and outflow using groundwater gradient changes. In addition, five cross sections including groundwater leveling and slope information at the desired time, as well as type of sediment deposits were used. In this study, it was found that groundwater inflow and outflow do not play an important role in aquifer volume in the region. Therefore, severe and local groundwater withdrawal due to over pumping, as well as changes in the volume and distribution of surface water resources, play a very important role in changing the direction and gradient of groundwater flows. There is a risk of saline water intrusion to the aquifers where there is a severe withdrawal in groundwater. In some areas, especially in the southern regions, the presence of underground dams of clay deposits with very high plasticity prevents the saline water intrusion into inland areas.