MODELING SEDIMENT DELIVERY IN ARID UPLAND BASINS

An upland sediment delivery model was developed for estimating the sed iment delivery rates at the rising, peak and recession stages of a flo w hydrograph in an arid upland basin. The model uses a steady state se diment continuity equation and a first order reaction model for deposi tion since the initial potential sediment load is always greater than the overland flow transport capacity, calculated by the Yalin method, in the arid regions. The model predicts the sediment delivery rates wi thin +/-10% accuracy at each hydrograph stage through calibration usin g slope and flow length combinations at the basin outlet. It is sensit ive to unit width discharge and the Manning's roughness coefficient. A simplified version of the Yalin equation when used with the model acc urately approximates the sediment delivery rates in the arid upland ba sins.