Abstarct: Lake Urmia is located in the northwest of Iran between the two provinces of East and West Azarbaijan. The lake's water level has dropped dramatically since two decades ago, with a significant portion become dry, especially in the southern half. Various reasons have been proposed as the causes of this event as well as different views about the role of groundwater in this event. Therefore, to investigate the quantitative and qualitative interaction of groundwater in coastal areas with lake water and other surface water resources such as rivers and wetlands on the southeast coast of Lake Urmia, this research has been carried out. This Study shows that in spite of the extensive expansion of agricultural activities and the increase of about 20,000 wells in 10 years and the relative increase in evaporation in this period, no significant drop in the level of alluvial aquifers has been observed also in the same time we observed relative stability of precipitation. Relative equilibrium in the groundwater level indicates the balance between the volume of water pumped and the return water to the alluvial aquifers. Hydraulic gradient of the Maragheh-Bonab aquifer is about 6 times greater than the Miandoab aquifer. The delay time between precipitation and its effect on groundwater level in the area of Miandoab plain is about one year and in the Maragheh-Bonab plain is about 4 years. The reason for this is that the role of irrigation return flows in recharging the Miandoab aquifer is more important than the Maragheh-Bonab aquifer. The important role of the return flows in the Miandoab plain is due to the existence of larger rivers and the existence of a large irrigation network in this plain. In areas where coarse grains exist and groundwater levels have reduced significantly (e.g., the southwestern regions of Maragheh-Bonab aquifer have dropped by about 13 meters in the past 10 years), the saline water intrusion toward the aquifer is greater. By comparing the water levels of lake and groundwater in the Miandoab plain, it is quite evident that they show different trends over the past two decades. For example, over the period from 2003 to 2010, groundwater levels have been increasing, unlike the decline in water levels in the lake. In addition, groundwater levels in the Miandoab plain have become more uniform in the last decade due to the relative balance of groundwater level. Finally, according to the results of this research, it can be said that agricultural activities indirectly played a significant role in the drying of Urmia Lake.