B P International

In this study, hydrodynamics and sediment concentration equations of partial differential in 3-dimensions were solved using finite difference methods, the Crank Nicolson procedure to predict both sediment concentration and velocity profile of Nun River. The computer software (EKU2.8) which is a modification of the Navier Stoke’s equations was employed for discretization of Nun River stretch of 2,000 m into 2,245 rectangular meshes and simulation of the river’s flow velocity distribution. The code was validated by using the field water current measurements obtained from a selected stretch of the river. Average predicted velocities of 0.85 m/s, 1.542 m/s and 0m/s compared favorably with 0.8m/s, 1.475 m/s and 0.09m/s obtained from field measurement for upstream, midstream and downstream boundaries. The predicted results have approximate correlation coefficients of 0.96 for velocity distribution using Pearson product-moment method. The model proved very useful in predicting the velocity...

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 semiar...

The use of riparian areas as water quality management tools, primarily derived from the studies of agricultural watersheds, where low phosphorus and large nitrate reductions in the suspended sediment are observed. A riparian strip performs many key functions, such as nutrient uptake, trapping of sediment or pesticides. Therefore, a number of different forms of protection strips have been applied in the field according to relief, steepness and location for use. Studies assessing technologies to design riparian strips using plant covers, based on sediment yield in river basins, are required for environmental protection. The removal of semi-shrubby, native vegetation in the Brazilian semiarid region, has contributed to the degradation of semiarid basins. The aim of this study was to design a riparian strip for the Jacu River in the semiarid region of Pernambuco as a function of sediment yield. Experiments were conducted during the years 2008-2011 in the Jacu River basin at Serra Talhad...