STUDING THE EFFECTS OF FACTORS DETERMINING WATER EROSION DEVELOPMENTS USING GIS-RS TECHNIQUES IN GHORI CHAY WATERSHED IN SOUTH OF ARDABIL, IRAN

摘要

In the current study, environmental factors affecting water erosion of the area, investigated in four categories, including topographic, soil & ground, vegetation and human factors. Considered parameters in each category are amongst effective factors of erosion in which differ in severity and weakness in various areas. Methodologically, mosaic of aerial photos created and work unit map was made using some basic watershed characteristics classified maps such as slope, geological formations and units. Four major types of water erosions including: sheet, rill, channel and riverbank which have considerable role on sediment yields of the area, were separately studied. So, the position and local distribution of various water erosion types of the area identified using photo-mosaics, satellite images and GIS-RS techniques. However, the local distribution and the effect level of each category of the water erosion investigated and the related maps of the factors affecting water erosion were supplied. In the next step, the effects of various factors on the occurrence of different water erosions were analyzed. The study was conducted using multivariate statistical tests. The test continued in three steps: i. frequency analysis, ii. abstract analysis and iii. multi-variable tests. Variables, entered in the models related to any erosion types obtained using selected parameters and results of the multi-variable analysis; and finally, resulted in regression models related to any type of water erosion. For each erosion types, an individual model was then presented.