Spatiotemporal Variations of Rainfall Erosivity Factor in Gorganroud Watershed

Dramatic increase of soil erosion due to the lack of proper management and inappropriate use of land is considered as one of main concerns of experts, researchers and decision makers in recent decades. the most important factor affecting soil erosion is rainfall erosivity. rainfall erosivity factor is used to describe the ability of rain to erode soil. Therefore, understanding of its spatiotemporal changes lead to planning, policy making and correct decision making of soil erosion control. Due to the effects of climate change on the extreme precipitation events, the timing of heavy rainfall occurrence has also changed. Determining the seasonality and the occurrence of erosive rainfall can be used in predicting natural hazards such as floods and erosion and reducing their destructive effects. Accordingly, the present study aims to analyze the spatiotemporal variations of the rainfall erosivity factor hazard in North-eastern of Iran, Golestan province. Toward this attempt and according to the purpose of the study, the amount of rainfall erosivity factor were calculated for 41 rain gauge stations with 42 years’ time span based on modified Fournier erosivity index in the Gorganroud watershed. Spatial investigation of rainfall erosivity index was provided by mapping mean, maximum, minimum and standard deviation of rainfall erosivity factor. Inverse Distance Weighting (IDW) and natural break algorithm were used for developing of maps and classification of mentioned maps, respectively. The spatial interpolations of the results were done in the ArcGIS environment.