Résumé
This contribution is concerned with the transport of sediment, primarily in suspension, by streams and rivers in Cameroun. A large number of drainage basins, representing the main climatic units of the country have been investigated simultaneously, with the frequency of sampling adapted to the range of hydrological regimes. These investigations aim to document the spatial variation of sediment transport and, more particularly, the impact of climatic and environmental change, both related and unrelated to human impact, on suspended sediment loads. The results presented here relate to six rivers with catchment areas ranging from 1500 to 18 000 km (super 2) . In this initial study, the procedures used to calculate, firstly, the mean concentration in the cross section and, secondly, the sediment load at the basin outlet are considered. Attention is first directed to testing the spatial representativeness of measurements of sediment concentration in the cross section, by considering the errors generated by varying the number of smapling verticals. Subsequently, temporal representativeness is considered by evaluating the errors introduced by varying the sampling frequency and the method employed for flux calculation. In the first case, errors of greater than 50% during high flows and 25% during lower flows are associated with a reduction in the number of sampling verticals from five to three. In the second case, the three methods employed for calculating the sediment flux are shown to produce very similar results. However, a reduction in sampling frequency by one half can introduce an error of 20%, and this can increase to 30% in the tropical zone.