十到百年尺度动力形态模型在珠江磨刀门河口的应用

A long-term numerical model of mophodynamic evolution and its application to Modaomen Estuary

在人类活动的参与下磨刀门河口演变已不再是纯粹的自然过程,而是自然和人类活动共同塑造的过程。建立了一个以过程模拟为主的10～100a尺度的长周期动力形态模型(PRD-LT-MM-10)用于模拟磨刀门河口在人类活动作用下的演变过程。该模型建立在水体运动方程和沉积物输运方程的基础上,应用约简技术对模型输入和计算进行处理,并包含了用于评价和量化人类活动的抛石促淤模块和航道疏浚模块。应用该模型较真实地模拟了磨刀门河口在1977-1988年的动力地形演变过程,并且通过模拟结果和情景分析,合理地分离了人类各种工程活动的长期影响和自然因素在河口演变中的作用。研究表明,治理工程对河口自然发展趋势造成了较大的改造,淤积强度表现为西侧大于东侧。抛石和围垦工程使横洲水道主槽逐年冲刷,深槽外移,而龙屎窟深槽上端则表现为严重淤积,深槽不断缩窄。

Modaomen estuary has been significantly changed by human activities and natural processes over the past decades.In order to study the evolution of the Modaomen Estuary during 1977-1988,a long-term（decadal-centennial scales） morphodynamic model which contains a rubble mound module and a waterway dredging mound module is developed to simulate the evolution of the Modaomen Estuary.The long-term simulation method and concept of model verification are discussed.Series of historical bathymetric charts are carefully analyzed to verify the model-simulated deposition and trends.The role of the human activities and natural process were separated based on the simulated result and situation analysis.The results of the numerical simulation and the morphodynamic analysis indicate that the sediment deposit of estuary on the west side is bigger than that on the east side,and affected by the riprap and reclamation project the main channel of Hengzhou is eroded by yearly,and the deep trough migrates seawards.However,the top of the Longshiku channel shows as severe deposition and channel continuously narrowing.