近几十年来珠江三角洲主要水文站设计洪潮水位变化原因分析

Analysis on the Causes of the Design Flood Level of the Main Hydrological Station in the Pearl River Delta in Recent Decades

近几十年来,在人类活动和气候变化的共同影响下,珠江三角洲水文情势发生较大变化。采用珠江三角洲及上下游水文站(潮位站)1970s以来径流、潮汐资料,分析发现珠江三角洲主要水文站设计洪水位发生了结构性变化,具体表现在马口、三水等三角洲上中部水文站(潮位站)设计洪水位降低,下部大部分口门控制站设计潮水位升高;建立了珠江三角洲河网、河口、近海非结构网格高精度二维水动力模型,模拟了上游洪水、河口潮汐、地形变化3种影响因素单独作用于珠江三角洲水动力系统时导致的珠江三角洲主要水文站设计洪潮水位变化情况,从而明晰了近几十年来珠江三角洲主要水文站设计洪潮水位变化的主要原因:地形变化是马口、三水等三角洲上中部水文站(潮位站)设计洪水位降低的主要原因,地形变化、洪量增加、强风暴潮、海平面上升均为三角洲中下部水文站(潮位站)设计洪水位变化的主要因子,各水文站(潮位站)主要影响因素差别较大。

In recent decades,the hydrological situation in the pearl river delta has changed greatly under the impact of human activities and climate change.This paper clearly stated that structural changes had taken place in the design flood level in hydrologic station(tidal station)of the pearl river delta and the upstream and the downstream through the analysis of runoff and tidal data of recent decades.The changes embodied in the design flood level reduced in the hydrological stations in the upstream and middle reaches of the pearl river delta,such as Makou and Sanshui station,but in creased in most hydrological stations in the downstream.This paper simulated how the design flood tidal level of the main hydrologic station inpearl river delta changed when three kinds of factors(upstream flood,estuarine tide and topographic changing)affecting the hydrodynamic system separately through a two-dimensional hydrodynamic model withunstructured grid and high resolution,then it clarified the main reason why the design flood tidal level of the main hydrologic station inpearl river delta changed in recent decades.Topographic changing was the main reason why the design flood level reduced in the hydrological stations in the upstream and middle reaches of the pearl river delta,such as Makou and Sanshui station.Topographic changing,flood increasing,strong storm surging,sea levels rising all were main factors of the design flood level changing in the downstream.There was a big difference between the main factors which would influence each hydrological station(tide level station).