Seasonal differences in the impacts of human activities on river-tidal dynamics in the Pearl River Networks in recent two decades
The dynamic characteristics in the Pearl River Delta(PRD)were disturbed by dramatic human activities and changed differently from the natural evolution.To explore the seasonal differences in the evolution of river-tide dynamic characteristics in the river networks of the PRD,based on the synchronous hydrological data of"997"and"177"during flood seasons and"012"and"1612"in dry seasons,the Fourier transform method was adopted to obtain the residual water level(RWL)and tidal components in the PRD for comparative analysis.The results showed that the RWL in the PRD decreased significantly in flood seasons and the decrease of the RWL was greater in the upper reaches;while the RWL increased slightly in dry seasons due to the increase of upstream inflow caused by reservoirs operation.At the same time,the tidal range of the PRD increased significantly in both flood and dry seasons.For a long time,the riverbed down-cutting caused by the changes of water and sediment discharges resulted from dam constructions in the Pearl River Basin was the leading factor for the decrease of RWL in the past 20 years.Moreover,the significant reduction of RWL slope caused by riverbed down-cutting revealed that the decrease of the resistance of tidal wave propagation in the river networks and attenuation of the decay effect of tidal wave amplitude were the main reasons for the increase of tidal range in the PRD channel networks.
Pearl River Deltaresidual water leveltidal rangehuman activities
NETL
NSTL
万方数据
维普
