Regression model for estimating annual sediment yield of small waresheds in West Azerbaijan

Sediment yield estimation for small basins is essential in watershed management planning projects. However، almost all of these basins are ungauged. In this study، in order to determine a range for specific sediment yield and to develop a regression model for estimating annual sediment yield، sedimentation behind small dams within 25 basins in Western Azerbaijan province، were measured. The selected basins with an area ranged 29 to 1200 ha، cover a range of lithology، land uses and climates and all of the sediments had been trapped behind the check dams. The specific sediment yields showed a two digit differences ranged 0. 12 and 12. However، the weighted average of specific sediment yield for all basins was calculated a low value of 1. 3. Study of relationship between annual sediment yield and 18 characteristics of watersheds using correlation matrix showed that the sediment yield is significantly affected by geologic erodibility، basin area and land use factors. From several regression models which were developed، an equation including two independent variables، geologic erodibility and basin area، with a high determination coefficient (R2=0. 899) was chosen.