Monitoring the Physical Surface Changes of the Gavkhoni Wetland and Its Relation with Dust and Its Surrounding Sand Dunes Activity

Gavkhuni wetland has faced numerous changes in its dry and humid surface due to some climatic and human factors in recent decades. This study aims to investigate the role of drought in producing and intensifying dust phenomena in the center and surrounding areas of Gavkhuni wetland. The physical changes of the wetland are first determined using remote sensing and GIS techniques. Then, the number of days with dust is identified using data measured at selected synoptic stations. Results showed that the wetland had its highest moisture level about 89% of the surface of water in 1993, and then there was a gradual decline each year since 1993. It has been more dried so that the wetland water level was less than 10% in 2013 and has been completely dried from 2013 to 2019. The results of the Lancaster index indicate most of the sand dunes in this area have been activated during the study period. Correlation analysis for annual and seasonal dust days at stations around wetland do not show a significant relationship with wetland drying condition in most of the stations. It is statistically significant for Isfahan station in spring and summer at 1%, and in autumn at 5%. However, since the direction of the Isfahan station storms is from west to east in spring and autumn, and the Gavkhuni wetland is located in the east of Isfahan, the relationship cannot be accepted. This relationship is significant for Shahreza station in summer and Aghda station in autumn at a 5% level. The directions of dust storms are from east to west towards Shahreza in summer, and from west to east towards Aqda in autumn. Therefore, increasing the trend of dust production in these two regions and seasons, considering the positive and significant correlation coefficient could be due to the dry surfaces of wetland in recent years.