瓯江河口及温州浅滩冲淤演变分析

Evolution of Oujiang estuary and Wenzhou shoal

基于瓯江河口和温州浅滩多年实测水文泥沙及地形水深资料,研究其冲淤演变特征。结果表明:瓯江流域径流量呈现年际、洪枯流量差别大的特点,此特性对瓯江河床冲淤变化起着至关重要的作用;瓯江口外及温州浅滩区域由于风浪作用引起泥沙再悬浮,导致其含沙量增大;瓯江河口地形表现为"洪冲枯淤"的特点,尽管河床纵、横向冲淤变化频繁,但河床冲淤幅度和河道容积在年间与年内变化不大,相对稳定;而温州浅滩则处于不断淤涨状态。特别是近期的人工围垦工程的建设进一步加大了其淤积速度,浅滩内普遍发生淤积,其中浅滩南端、北段及邻近灵霓大堤附近淤积最甚。同时,温州浅滩靠南口水道部分由于灵霓北堤建设及完成后封堵了其北侧上浅滩的潮量,从而加大了大、小霓屿岛间进入浅滩的潮量,使得其在1999—2010年间处于冲刷的状态。

Based on the measured data of hydrological sediment and water depth over multiple years inOujiang River estuary and Wenzhou shoal , this paper studies the evolution characteristics of scouring and silting.The results show that the runoff in Oujiang River basin is characterized by the difference of annual and flood fluxes, which plays a crucial role in the erosion and deposition of the Oujiang riverbed.Muddy sand suspends again at the Oujiang River estuary and the Wenzhou shoal area due to the wind and wave actions , resulting in an increased sediment concentration. Oujiang estuary topography behaves a “flood season erosion and dry season sedimentation ”features.Although the vertical and horizontal erosion and deposition of the riverbed changes frequently , the year-to-year changes of the bed erosion and sediment amplitude and river volume is little, and the riverbed is relatively stable.But Wenzhou shoal is in a state of continuous siltation.In particular , the construction of the recent reclamation project has further accelerated its deposition rate.Silting generally occurs at the shoals , and the sedimentation is most frequent near the southern end of the shoal and the northern section of the shoal near the Liten River dike.At thesame time , since Wenzhou shoal near the south exit waterway blocked the tidal volume from the northern side due tothe construction and completion of the Lingdi north dike , the tidal volume entering the shoal between the large andsmall islands increased , so it was in the state of erosion from1999 to 2010.