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–84 used 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 0.165 and ranged from
0.29 in the year 2008 to 0.026 in 2010. 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.