中文摘要：

采用数值模拟与实测资料相结合的方法研究了北江下游推移质输沙率公式的适用性、洪枯季推移质输沙率及空间分布。结果表明以切应力为主要参量的推移质输沙率公式较适用于北江下游河道,洪季Bijker公式、枯季Van Rijn公式计算误差较小。石角断面洪季推移质输沙率为9.06万t/月,枯季为2.43万t/月,年推移质输沙量为49.54万t。推移质输沙主要集中在大塘以上河段,洪枯季均在山塘上游、廻岐洲、界牌洲等处出现输沙率峰值,大塘下游推移质输沙较弱。水面比降是推移质输沙率沿程变化的主导因素。

英文摘要：

Applicability of bed-load transport formulas, and the amount and distribution of the sediment trans- port rates in the lower reaches of Beijiang River were studied. Results indicate that formulas based on bottom shear stress are more suitable in study area. The minimum error was found by Bijker formula in flood season and Van Rijn formula in dry season. Bedload transport rates at Shijiao section were calculated, which were 9.06 ~ 104 tons per month in flood season, 2.43×10^4 tons per month in dry season, and 49.54 ×10^4 tons for the annual bedload discharge in 2002. Bedload transport mainly located in the upper reach of Datang, peaks of the sediment transport rate exist in cross sections at Shantang, Huiqizhou and Jiepai. Bedload transport was weak in the lower reach of Datang. Hydraulic slope is the dominant factor affecting spatial distribution of the bedload transport.