再论瓯江口拦门沙回淤及治理研究

Further study on back silting and regulation of mouth bar in Oujing esturary

分析了瓯江口拦门沙在自然状态下、一期整治工程实施后的泥沙回淤情况,分析表明影响拦门沙回淤的主要因素为周边滩面上的风浪掀沙和上游洪水来沙.在泥沙回淤验证的基础上,应用波流共同作用下的二维泥沙数学模型,研究了拦门沙航道二期整治工程效果,预测了正常水文条件下的泥沙回淤及台风期骤淤.整治工程具有减少风浪掀沙和归顺水流等作用,取得了较好的整治效果,正常水文条件下减淤幅度为14.1%～23.1%,台风期减淤幅度为23.3%～35.7%.

Siltation under natural conditions and after implementation of the first stage of regulation projects of the mouth bar in the Oujiang estuary is analysed.The results show that the back-silting in the mouth bar is mainly influenced by wave-induced sediment suspension and flood from upstream.Based on verification,a 2D sediment mathematical model under the co-action of waves and tidal currents is employed to study the second stage regulation project of the mouth bar channel.Then the back silting in navigation channel under normal hydrological conditions and the sudden siltation due to typhoon are further predicted.The regulation projects can reduce wave-induced sediment concentration and adjust tidal flow in the mouth bar channel.Back silting in the channel can be reduced by 14.1%～23.1% under normal hydrological conditions,and by 23.3%～35.7% in typhoon days.