1-D NUMERICAL MODEL OF FLOW MOTION AND SUSPENDED-SEDIMENT TRANSPORTION IN RIVER NETWORKS OF THE PEARL RIVER DELTA

摘要

The Pearl River Delta lies in the south of the GuangDong province of China. It is the river network area of the lower reaches of MaKou of Xijiang River, Sanshui of Beijiang River and ShiLong of Dongjiang River. The Pearl River Delta is the flood plain, among which Xijiang and Beijiang River Deltas include the river network area from Makou, Sanshui to the eight estuaries. The surface area of the Pearl River Delta is 9,750km~2, among which Xijiang and Beijiang River Delta is about 8,370 km~2, accounting for 85.8% of the whole delta/and Dongjiang River Delta is 1,380 km~2, accounting for 14.2%. Rivers in this area interlace each other, and the river current is affected prominently by the tides. Based on the Saint-Venant equations and the non-equilibrium transport equation for the suspended-sediment, a numerical model of junction- river course for the whole Pearl River Delta is established in this paper by using the junction-control methods for water level and sediment concentration. Firstly, the river network in the Pearl River Delta is schematized as 340 main river courses, 216 nodes and 1,850 cross sections. The area of river network in this model is about 2,000km~2, and the total length is more than 1,600km. Secondly, the equations are divided into three steps as the river sections, river courses and the branch nodes. The algorithm for the sediment transport in the river networks is similar to that for unsteady flow. Finally the water level, flux, and sediment concentration at every section in the river network are calculated. Representative period field data are used to verify the model. It is testified that the calculation agrees with the observed data.