Effects of wind velocity and soil characteristics on dust storm generation in Hawr-al-Azim Wetland, Southwest Iran

Nowadays, dust storms are an important environmental problem in Iran (especially in Khuzestan Province). The Hawr-al-Azim Wetland is a source for generation of dust storms. One-third area of this wetland is located in Iran. In this study, dust discharge is calculated using wind velocity, mean soil grain size (D۵۰) and soil dry density. Soil characteristics were determined by data collected from ۱۶ boreholes drilled in this wetland. Distributions of D۵۰ and soil dry density in the wetland were determined using ordinary kriging method. Then critical wind speed was calculated in different regions of the wetland. The wetland soil is composed of medium and coarse silty soil. The dust mass discharge has reduced from ۲۰۰۳. The maximum monthly dust discharge mass occurs in June and July (along with a mean monthly wind velocity of ۴.۴۲ m s-۱ and ۴.۲۷ m s-۱, respectively). Because of the little amount of clay particles and the high wind velocity, increased soil moisture content cannot help in neither raise inthe critical shear velocity nor decreased dust mass discharge. Also, the produced dust is transported towards Northwest Iran because the dominant direction of wind is ۲۷۰° to ۳۰۰° relative to the north.

کلیدواژه ها:

Critical shear velocity ، Dust mass discharge ، Soil moisture content ، Hawr-al-Azim Wetland ، Wind erosion