Evaluating of Sediment Delivery Ratio on Spatial and Temporal Variabilities in Semiarid Watershed Brazil

Evaluation of sediment delivery ratio is important for determining watershed sediment yield. Rates of both interrill and rill erosion were calculated under shrub and uncovered Inceptisols conditions and were not observed to the presence by ravines and gullies in the watershed of Jacu River, in a semiarid region, Brazil. Direct measurement campaigns of suspended sediment and bedload were also carried out by means of the US DH–48 for collection of suspended sediment samples and US BLH–84used to collect samples bed load. The soil loss due to interril erosion under uncovered conditions was equal to 8.43 t ha-1 and was considered high, and the same was true for the values of rill erosion with erodibility equal to 0.0021142 kg N-1 s-1 and critical shear stress (τc) equal to 2.34 Pa. The mean value of sediment delivery ratio of Jacu watershed was equal to .165 and ranged from .29 in the year 2 8 to . 26 in 2 1 . This variation was associated with the natural variability of semiarid environment, indicating the necessity of assessment for a longer period to deepen our knowledge of sediment delivery ratio of the Jacu semiarid watershed.