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چکیده
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Lake Urmia, the largest inland lake in Iran, has faced a drought crisis in recent years due to a significant decrease in the lake's water level as a result of climate change, human activities, and the construction of numerous dams in its catchment area. This study uses satellite data to identify the causes of the drying up of Lake Urmia and analyzes the human and natural factors affecting the decrease in the lake's water level. Changes in the ecosystem and area of the lake have been investigated using Sentinel images (2017 and 2023) and the NDVI method. Based on data analysis, it has been determined that construction land, which was about 133,796.09 hectares in 2017, has increased to 188,779.40 hectares at the end of the period, garden land has increased from 5696.88 hectares in 2017 to 6744.38 hectares in 2023, and cropland has increased from 979,333.07 hectares in 2017 to 1380,279.62 hectares in 2023. Also, the amount of water has decreased from 134,726.55 hectares in 2017 to 49,401.57 hectares in 2023. Also, the NDVI maps of the Urmia Lake basin in the period from 2017 to 2023 indicate that the numerical value of this index in 2017 is between 0.810 and 0.018 and for 2023 it is between 0.834 and -0.112, which indicates that due to the increase in garden and agricultural lands, a large volume of water in the Urmia Basin has dried up. On the other hand, due to the exploitation of 39 dams around the Urmia Lake basin, the water entering the lake has decreased sharply. The results show that the drying up and the decline in the health of the Urmia Lake basin ecosystem are due to the following three main factors: unsustainable development of the agricultural sector, the construction of numerous dams around the lake to exploit the water of the basin, and the intensification of climate change along with the occurrence of drought, which are among other factors..
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