INVESTIGATION OF 2019 RAINFALL EFFECTS ON URMIA LAKE SURFACE AND EXTRACTION OF LAKE SHORELINE CHANGES AND COMPARISON WITH THE PREVIOUS DECADE USING REMOTE SENSING IMAGES AND GIS

Abstract. Urmia Lake has experienced many fluctuations during recent decades, which played a key role in the socio-economic changes in the north-western part of Iran. Consequently, socio-economic planning and land management around the lake require anticipation of changes’ trend. In this paper, regarding continual rainfall in the beginning of 2019, shoreline and water level changes of this lake have been studied and compared to the previous decade. To this aim, Landsat satellite imagery (Oli, ETM and TM sensors’ images) was used to extract NDWI index by using Green and NIR bands. The results of this study showed that Urmia Lake has declined over the past ten years and reached its lowest level in the year 2015. However, due to rainfall of 2019, these changes have had ascending trend which made water area equal to the situation in 2010. It, also was observed that similar to the trend of water level, the shoreline has progressed toward the Lake from the east and the south and become salt marsh. But, the West and the North parts have not changed significantly. Then, in 2019 salt marsh lands have been submerged once again, and the vast eastern island, which was completely blended in with the surrounding lands, returned to its previous state, the peninsula. In addition, considering the trend of rainfall and Lake’s restoring activities, the minimum and maximum time required to reach the area in 2010 were estimated 23 and 38 years respectively, assuming the volume of precipitation remains constant and the reduction of these activities at a constant rate.