effect of land use changes on runoff depth in chalousrud watershed

due to the importance of the role of land use changes on runoff changes, several studies have taken place to develop models with simulating land use changes. in this study, the l-thia model was used for estimating the runoff made by land use changes in chalousrud watershed. results of runoff modeling using l-thia model showed that runoff depth increased from 422.98mm to 809.168mm during 1984 to 2000 that state an increase in runoff depth of 368.18 mm during 16 years and during 2000 to 2006 from 809.168mm to 825.496mm that state an increase 16.32 mm during 6 years. the results show that surface runoff depth increased due to decreasing of forest land with 3527.13ha from 58907.31ha to 55380.08ha and increasing of urban land with 7757.58ha from 7757.58ha to 362.50ha and increasing of abandoned land with 23176.01ha from 720.29ha to 23996.3ha. as a result of this study the l-thia model has acceptable ability in explaining the way of land use changes effect on volume and depth of runoff. this model could provide the possibility of identifying accident prone areas, flood zones and flood management by spatial distribution map of runoff.