Verification of the musle to determine the amount of suspended sediment

anglais. This paper evaluates the possibility of determining the transport of suspended sediment removed from two catchments with different physiographic conditions and varying hydrological regime, as well as with different catchment's land use. Two rivers, one mountain and one lowland, were selected for the experiment. The sediment transport was determined by USLE, with sediment delivery ratio (SDR). Mean annual transport of suspended sediment, calculated based on hydrometric measurements, including mean daily flows and the corresponding concentrations of suspended sediment, were compared with the values of the mean annual sediment transport calculated using USLE method with SDR and MUSLE method. Having flow hydrographs and the specified mean annual mass of eroded soil in the catchment, the total sediment transport was calculated based on the MUSLE equation. The results of calculations according to the MUSLE in its original form given by Williams & Berndt and in the modification of Banasik & Madeyski proved to be significantly higher than those obtained based on measurements – respectively over 16 and 4 times higher in the mountain river Wisłoka and over 4 and 0.8 times higher in the lowland river Dłubnia. With hydrological data for those rivers, the MUSLE equation was calibrated and α and β coefficients of the MUSLE were determined, amounting respectively to 0.0006 and 0.9065 for the mountain river Wisłoka and 0.0029 and 0.9262 for the lowland river Dłubnia. The calculated coefficients α and β of the MUSLE, both for the mountain river Wisłoka and the lowland river Dłubnia, differ considerably from the ones proposed by Williams and Brendt, as well as by Banasik and Madeyski. Due to the heterogeneous nature of the erosion and transport processes, their modeling by the MUSLE in its original form is highly uncertain and difficult in the case of any catchment.

anglais. erosion, sediment delivery ratio, sediment yield, MUSLE

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235-244

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