Urmia Lake is the largest inland wetland in Iran, which is shrinking. The gradual drying of Lake Urmia has been a national and international issue for several years. In recent decades, climate change, dam constrictions, unsustainable industrial development and excess exploitation of groundwater for agriculture have been the main cause of drying of Lake Urmia. It has been proven that in the case of lakes drying up, this change has an effect on the global climate. Considering the salinity of Urmia Lake and direction of the wind (principally in a W-E trending), the eastern coastal area of Urmia Lake is seriously in danger of salt intrusion into the soil and underground water that can totally affect the lives of the local population. It also endangers the existence of fauna and flora. This paper attempts to clarify the danger of drying Urmia Lake and salt dumping at the beds of lake and determine the effective parameters, using GIS® and ENVI software. Among the causes of Urmia lake dryness, the dam constrictions have been identified as the cases that has more drastic effects on Urmia lake. تفاصيل المقالة

To investigate the pollutants of the Kor River, water samples were collected during the rice-growing season in 2014. The first fertilizer was diammonium phosphate ((NH4)2HPO4). After first irrigation, supplemented with fertilizer usage, in the upper layers of soil causes an increase of NO3− concentrations to reach from 7.3 to 25.7 mgl-1 at the agricultural lands beside the Sarbast village. At this point, the NO3− concentration was 5.3 mgl-1. After the application of the third fertilizer (by using of urea fertilizer) flood irrigation, lead to decreasing of NO3− concentration at surface soil samples to 3.5 mgl-. At the same time, before first fertilizer application at the soils located beside of Doroodzan Lake the NO3− concentration was 17.9 mgl-1 but after the first fertilizing it increased up to 31.4 mgl-1. Therefore, the NO3− concentrations (31.4 mgl-1) exceeded from the acceptable limits for drinking water at this site. During the second and the third periods of urea fertilizer application, at this point the NO3− concentration decreased from 4.43 mgl-1 to 2.2 mgl-1. In spite of using high amounts of fertilizer because of flood irrigation, the NO3− concentrations leaches to surface groundwater. The maximum nitrate pollution occurs in June, when the rice plants are in the early stage of growth. As rice canopy coverage is increased, the nitrate concentration reduced. The result focuses on the vital roles of plant coverage in nitrate absorption. If the fertilizer is rationally applied, phosphate loading into the river will be minimized. The rationality behind these procedures is explained. تفاصيل المقالة