Assessing the Effects of Land use and Land Cover Change on the Flood Regime of Tajan Basin Using Remote Sensing Technique

Abstract
In order to study the type and range of the changes in TAJAN basin, in recent year, the images of TM and ETM+ were studied. For assessment of land use changes after enhancement and geometric correction, differencing change detection techniques, false color composite, vegetation index and post- classification comparison methods were used. The result of this study indicates the extended land use changes including decrease of forest extent, rangeland and increase of agricultural land and gardens. Analysis of runoff and rainfall from 1969-1970 to 2000-2001 periods indicates that in spite of decrease of rainfall amounts, the runoff has increased ,while the total mean of vegetation index and the mean of vegetation index of forest and rangeland has decreased about 12.89, 9.85, 34.7 percent respectively. With consideration of stability of topography, slope gradient results show runoff increased in this area due to decrease of vegetation. Therefore climatic and environmental factors had not important role on increase of runoff in studied basin.

keywords: Land use and land cover change, TAJAN, Vegetation index, TM, ETM+ .