Assessing the Vulnerability to Soil Erosion of the Mahabad Dam Drainage Basin Using Remote Sensing and GIS

The drainage basin of Mahabad Dam has been exposed to severe erosion as a result of land use change. In this basin sediment yield takes place in only two measuring stations; therefore, it is often difficult in smaller basins to locate erodible areas and to plan land use and conservation. To do this, one way is to categorize areas with different erosion susceptibility based on certain parameters used in this study. These parameters are slope, altitude, rock erodibility, land use, precipitation and concentration time. The distribution maps prepared on each of these parameters and their overlaps have shown that areas with more severe slopes and higher rock erodibility are categorized as highly susceptible to erosion. However, in areas with resistant rocks, change of land use has been the determining factor. Land use is the only parameter modified by man, and it is the only one which can be quickly and effectively changed. Hence, it seems that the upstream areas of basins with low concentration time, severe slope, high erodibility, and high precipitation, yet with forest and pasturing coverage, are in greater need of preventative measures.