兴化湾潮汐潮流特性及工程影响分析

福建省兴化湾内大量围填、疏浚工程建设直接影响湾内水动力环境。依据2009年2月水文观测资料,对实测资料进行分析,并利用潮汐调和分析、潮流准调和分析、潮流数值模拟等方法得到了兴化湾海区的潮汐、潮流特性以及湾内工程前后的潮位、潮流场和余流场特征。分析研究表明,兴化湾潮汐属于正规半日潮,浅水效应较弱;潮流为不正规半日潮流,浅海分潮作用较强;湾内潮波逐渐有驻波特征,形成湾内潮波的两股潮流流向稳定,呈往复流,其中兴化水道潮流涨潮占优,南日水道潮流落潮占优;工程实施后,基于调和常数的2013年7月潮位预报与实测潮位吻合较好,同时潮汐潮流性质不变,在港池、航道水域流速有所增加;兴化、南日两水道涨、落潮通量均减小,全湾纳潮量有所减少;湾内余流场整体不变,口门处涡漩有所加强。

Tidal regime and impacts of works in Xinghua bay on hydrodynamics

The Xinghua bay, located in the west of Taiwan Strait, has a large scale of reclamation and dredging works which will directly have impacts on the hydrodynamic environment. Based on the hydrological measurement data of February 2009, studies of characteristics of tidal level, current field and residential field with and without works are conducted by using the method of tidal harmonic analysis and current harmonic analysis, and a tidal flow mathematical model. As the analysis results show, in the Xinghua bay, the tide is a regular semidiurnal tide with subtle shoaling while the tidal current is a regular semidiurnal shallow current. From the outside to inside, the tide wave which is composed of stable direction tides of the Xinghua waterway and Nanri waterway has some characteristics of the standing wave, and the spring tide is dominants in the Xinghua waterway while the ebb is dominant in the Nanri waterway. After completion of works, the forecast tidal process lines of July 2013 based on the harmonic constants are in good agreement with the observational ones, and at the same time the characteristics of tide and current are kept the same. Velocities within the harbor and channel increase slightly. The tide fluxs of both the Xinghua waterway cross section and Nanri waterway cross section decrease, as well as the tidal prisms. And the Eulerian residual current field remains unchanged in the whole bay while the vortexes in the entrance areas are strengthened.