Lake Urmia (LU), which once had been the second largest hypersaline lake in the world, and greatest in the Middle East, has undergone severe environmental changes during recent years that have led to widespread desiccation. These changes have converted the lakebed into a significant Aeolian mineral source, which promotes aerosol plumes that can seriously impact downwind regions. A question remains as to how significant emissions are from LU as compared to others impacting the West and East Azarbaijan provinces encompassing LU. This study uses daily Aerosol Optical Depth (AOD) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) between 2001 and 2015 to show that AOD levels are significantly larger in the latter half of the study period (2008-2015) with AOD values in the West consistently being lower but approaching those of the East with time owing to a combination of increasing emissions from the West province and neighboring areas. While the interannual AOD profile over Azarbaijan resembles that of Iraq owing to transported dust, signatures of the local impact of increasing emissions is evident over the 15-year time period, especially in the months outside of the peak dust season (January, February and October) and on the immediate periphery of LU. Consequently, the spatial profile of AOD over Azarbaijan is not uniform but with distinct hot spot. The onset of the spring AOD ramp-up over Azarbaijan is shown to have started earlier (in February) when comparing 2009-2015 versus earlier years. Correlative analysis confirms that AOD is related to factors promoting dust emissions but also reveals that smoke contributes to AOD over Azarbaijan during the summer months.

The Lake Urmia positioned in a closed basin in north-west Iran, positioned at altitude 1250 m above the sea level, and has been rapidly drying since 1990. The lake water level has declined to 1271.58 m in 2008 from the last highest record 1277.80 m in 1994. The lake water volume has fluctuated during the observation period and shows a drop from of 32 to 14.5 million cubic meters, while the lake salinity has increased from 205 to 338 g/l due to the evaporation and water inflow reduction. In the Lake Urmia basin, there has been an increase in public awareness of the possible environmental threat and the unpleasant socio-economical consequences on the region’s inhabitants.  The main aim of this study is to assess the current water use pattern in the Urmia Lake basin system with emphasis on the agricultural sub-system, and to propose adaptive measures and sustainable water management scenarios. The study shows that the main cause for these changes are the diversion of rivers and streams for agricultural irrigation; agriculture is a sector with one of the highest water demands, and frequent drought in early 2000s exacerbated the situation. In addition, a growing population and the increased development of agricultural land has led to an increase in unsustainable practices which have an unpredictable impact on the Lake Urmia ecosystem. This study investigates sustainable water use strategies for Lake Urmia basin, and considers economic and environmental factors, including the loss of valuable ecosystems that highlights social and ethical issues for the current and coming generations.

Lake Urmia, located in the north-west of Iran, is one of the largest hypersaline lakes in the world. In recent years, there has been a significant decrease in the lake’s area and volume by 88% and 80% respectively. An integrated water balance model of the Lake Urmia Drainage Basin (LUDB) and Lake Urmia was developed to identify these main drivers of the significant changes, and to investigate the possible future evolution of the lake under effects of projected climate change and land use change. We used an energy balance method to estimate the evaporation from the lake and the Turc-Langbein method to estimate the evapotranspiration from the drainage basin of the lake. Agricultural irrigation water was introduced to the model as an extra precipitation over the irrigated fields, after being subtracted from the surplus runoff (precipitation−evapotranspiration). The agricultural land development was assumed to be linear that changed from 300000 ha at 1979 to 500000 at 2010, which is consistent with the best available data on the actual irrigation development in the basin. We estimated the annual evaporation over the Lake Urmia and the evapotranspiration over its drainage basin as 932 mm and 287 mm respectively. Our results showed that decreased precipitation and increased temperature over the basin since 1995 could explain 68% of the observed lake level decrease. Irrigation developments during the last four decades were found to be responsible for 32% of the observed lake level decrease. Thus the future lake level of the Lake Urmia is very likely to continue to decrease unless the current climate condition will be followed by a period of increased precipitation. If the current climate conditions will prevail also in the future, even a 20% decrease in the irrigated land area, which is actually quite ambitious, will not make the lake recover to its ecological level at the end of 2020.