Analysis of Changes in the Area of Hamoon Wetlands andother Water Bodies in Sistan Region using Satellite Images

Sistan region is one of the important regions whose life depends on the flow of Hirmand river. In this research, the trend of changes in the area of Hamoon wetlands and the factors affecting it, were investigated using satellite and meteorological data. For this purpose, the minimum, maximum, average temperature, precipitation and evaporation of Zabol station were used in the period of 1985-2018. Furthermore, satellite products include water bodies extracted from Landsat satellite images (JRC products 1985-2020), NDVI, PDSI, Sentinel 2 and GRACE satellite data used in the period of 2000-2022. The man-Kendall and Sen’s slope tests were used for evaluating time series trends of data. AWEI index was used to calculate the water areas of Sistan region. The results show a significant decrease the minimum, maximum, average temperature, precipitation, area of permanent water bodies, GRACE and PDSI. On the other hand, the changes in NDVI showed a significant increasing trend, which is caused by the quantitative development of agricultural lands in the Sistan plain. Also, the anthropogenic activities of Afghanistan have an impact on this river entering Iran. The results of the AWEI index showed that after the full exploitation of the Kamal Khan diversion dam, the natural flow of the Hirmand River has been diverted towards Gowdzereh in such a way that the area of water flowing in Gowdzereh is more than 34000 hectares and the area of water behind the Kamal-Khan dam is equal to 2899 hectares, which confirms the diversion effect of Kamal Khan Dam.