珠江网河水沙分配变化及其对伶仃洋水沙场的影响

Changing water and sediment dynamics in the Pearl River network and consequences on water and sediment regimes in the Lingdingyang estuary

摘要: 采用二维ECOMSED模型对径流来水来沙变化前后的1978年和1999年伶仃洋洪水期水动力场和悬沙场进行模拟,结果表明:伶仃洋水动力场整体增强,但不同地貌单元水动力变化具有明显差异.分流比变化后洪水期伶仃洋西槽、东槽和中滩水动力增强,涨潮和落潮流速普遍增大0.1m/s;西部各口门区和西滩涨潮流势减弱,径流优势更加明显,但西滩三个口门水道及滩面潮沟落潮流速增大约0.1 m/s;东滩水动力特征变化不大.悬沙浓度亦整体升高,平均增加了0.02~0.05 kg/m³,悬沙高值区范围扩大,0.10 kg/m³等值线由西槽西侧明显向东推进到沿东槽南北向分布,径流来沙的影响范围东扩.

Abstract: A 2-dimensional model is used to simulate the hydrodynamic and sediment fields of the Lingdingyang estuary(LDYE) in flood seasons of 1978 and 1999.The results show the hydrodynamics and suspended sediment dynamics have been largely altered.The hydrodynamics of the LDYE is strengthened in flood seasons,with the alterations varying in different areas.The flood and ebb tidal velocities increase by 0.10 m/s in the west and east channels and the middle shoal.As a whole,the sediment concentration of the LDYE increases by 0.02-0.05 kg/m³.The high concentration area is enlarged,and the isocline of 0.10 kg/m³ extends from the west channel to the east channel,indicating that the influence of fluvial sediment has enhanced markedly.