Shoal Bypassing in Mixed Energy Inlets: Geomorphic Variables and Empirical Predictions for Nine South Carolina Inlets
Shoal Bypassing in Mixed Energy Inlets: Geomorphic Variables and Empirical Predictions for Nine South Carolina Inlets
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发表时间：
2001-04
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通讯作者：
Daniel J. Gaudiano;T. Kana
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作者：
Daniel J. Gaudiano;T. Kana
在混合能量环境中，潮汐汊道经历了一个被称为浅滩绕过的幕式过程，由此离散的砂坝从落潮三角洲释放并向岸上迁移。这些事件可以将大量的沙子以向陆地迁移的浅滩的形式输送到邻近的海滩。在南卡罗来纳州的九个潮汐入口进行了分析，以确定是否有可预测的关系之间的砂量在落潮三角洲和在个别绕过浅滩，绕过事件之间的时间间隔，和潮汐棱镜。跨越58年的历史照片产生了221个离散的浅滩在不同阶段的绕过分析。在KANA（1995）早期工作的基础上，发现平均绕浅滩事件时间间隔和平均绕浅滩体积与潮汐棱柱有关。较大的入口比较小的入口经历浅滩绕过事件的频率低，但产生较大的绕过浅滩体积。平均事件间隔与潮汐棱柱体的关系式为I = 0.046Tp + 4.56，其中I为平均绕滩事件间隔（年），Tp为潮汐棱柱体（106m3）。平均浅滩体积与潮汐棱柱体的关系为S = 6.42Tp + 113.4，其中S为平均绕流浅滩体积（103m3）。这两种关系在统计上都很重要。平均而言，浅水浅滩占其各自落潮三角洲体积的小体积百分比（0.6%至6.6%），但在中潮、中等波能环境中，如南卡罗来纳州，浅滩绕过可能是促成局部增生海滩的最重要过程。
In mixed energy settings, tidal inlets undergo an episodic process known as shoal bypassing, whereby discrete bars are released from the ebb-tidal delta and migrate onshore. Such events can transport large volumes of sand, in the form of landward-migrating shoals, to adjacent beaches. Nine tidal inlets in South Carolina were analyzed to determine if there are predictable relationships among the volume of sand in the ebb-tidal deltas and in the individual bypassing shoals, the time interval between bypassing events, and the tidal prism. Historical photographs spanning up to 58 years yielded 221 discrete shoals at various stages of bypassing for the analysis. Building on earlier work by KANA (1995), mean shoal-bypassing event time intervals and the mean bypassing shoal volumes were found to be related to tidal prism. Larger inlets underwent shoal-bypassing events less frequently than smaller inlets, but produced larger bypassing shoal volumes. The relationship between average event interval and tidal prism was based on the equation, I = 0.046Tp + 4.56, where I is the average shoal-bypassing event interval (years) and Tp is the tidal prism (10 6 m 3 ). The relationship between average shoal volume and tidal prism was based on the equation, S = 6.42Tp + 113.4, where S is the average bypassing shoal volume (10 3 m 3 ). Both relationships are statistically significant. Bypassing shoals represented, on average, small volumetric percentages (0.6% to 6.6%) of their respective ebb-tidal delta volumes, yet in mesotidal, moderate wave energy settings such as South Carolina, shoal bypassing can be the single most important process contributing to a locally accreting beach.