巩明，李伯根，周鸿权

(国家海洋局第二海洋研究所 国家海洋局工程海洋学重点实验室，浙江 杭州 310012)

乐清湾大乌港水道冲淤变化分析

巩明，李伯根，周鸿权

(国家海洋局第二海洋研究所 国家海洋局工程海洋学重点实验室，浙江 杭州 310012)

大乌港水道位于乐清湾中湾西侧，是乐清湾内外湾水沙交换的主要潮流通道之一。根据1933-2005年间5个年份的水深地形资料，采用GIS技术建立大乌港水道不同年份的数字高程模型（DEM）。通过模型叠合对大乌港水道近70年间进行数字化冲淤定量计算，结合实测水文泥沙、地貌形态、人类开发活动等资料综合分析表明：大乌港水道整体上处于缓慢淤积的趋势，其南北两端潮流分汇流缓流区的淤积幅度大于中间的潮流畅通区段，断面形态及深槽位置未发生大的改变；堵港、围涂等人类活动加速了大乌港水道的淤积过程。

乐清湾；潮流通道；冲淤变化

Abstract: Dawugang channel is located in the west of the middle bay of Yueqing Bay, which is one of the main tidal channel where water and sediment exchange between inner bay and outer bay, with abundant deepwater coastal areas.Supported by GIS, five bathyorographical maps from 1933 to 2005 are transformed to digital elevation models to calculate the amount of the erosion and deposition and analyse the general trend of the erosion and deposition, also based on the data of the observed tidal current, suspended sediment, geomorphology, etc.It is shown that Dawugang channel is in a slow sedimentation trend on the whole, the area of slack water where the tidal current separates and joins at both ends depositing more than the middle part where the current can flow freely, and the form of the cross section and the site of the groove don’t change greatly.Besides, coastal engineerings such as reclamation speed up the deposition of Dawugang channel.

Keywords: Yueqing bay; tidal channel; erosional and depositional change

引 言

我国东南沿岸发育着众多的基岩淤泥质海湾，从北往南依次为象山港、三门湾、乐清湾、沙埕港、三沙湾、福清湾等海湾，湾内拥有岛礁、水道、滩涂、深水岸线等多种空间资源，乐清湾便是其中比较典型的一个。它位于浙江沿海南部，瓯江口、温州湾北侧，向西南开口，其东北西三面为低山丘陵环绕，1977年漩门堵口后，乐清湾从一个潮流通道型海湾变为为一个典型的半封闭海湾（图1）。湾内岛屿众多，岛屿之间，岛陆之间形成潮流通道[1]。大乌港水道便是其中规模较大的一支，拥有丰富的港口和航道资源。……