Analysis on the Characteristics of Bed Materials in the Jinghong Reservoir on the Lancang River

Nine samples of bed materials along the Jinghong reservoir on the Lancang River were obtained using a gravity sampler. The grain size characteristics of the samples were analyzed by the laser diffraction particle size analyzer. The results show that the median grain size of bed materials is in the range of 6.7 to 18.9 µm. From the upstream to the front of the dam, the overall grain size of the bed materials tends to decrease significantly; the sorting is poor but becomes better along the way; the skewness gradually changes from negative to near symmetrical; the kurtosis is platykurtic and mesokurtic with little change along the way. Based on the measured data, an exponential model is constructed to describe the distribution of representative grain size of bed materials along the way. Furthermore, the concept of representative particle Reynolds number is proposed. The relationship between representative particle Reynolds number and flow parameters with boundary conditions is established, and the coefficient and exponents in the equation are determined based on the measured data of the Jinghong reservoir. This study provides valuable first-hand information for reservoir sediment research and new ideas for sediment sorting and deposition studies.