Longshore sediment transport rates on a reef-fronted beach: Field data and empirical models Kaanapali Beach, Hawaii
Longshore sediment transport rates on a reef-fronted beach: Field data and empirical models Kaanapali Beach, Hawaii
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发表时间：
2003
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通讯作者：
D. Eversole;C. Fletcher
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作者：
D. Eversole;C. Fletcher
沿岸泥沙输运（LST）测量每月海滩配置文件Kaanapali海滩，毛伊岛进行比较，三个预测模型。夏季和冬季的净输沙量分别为29,379 ±4400 m3/yr和22,358 ±1300 m3/yr。Kaanapali海滩北部的净年增长率为7，021 ±700 m 3 /年，总年增长率为51，736 ±5100 m 3 /年。CERC（1984）、CERC，1991（GENESIS）和KAMPHIUS（1991）等输运模式预测的净年LST率分别为观测值的3 × 103%、77%和6 × 103%。成因模式的成功归因于其解释近岸参数短期变化的能力。CERC（1984）的使用在实际应用中容易出现错误，包括使用推荐的K系数和波浪平均，这可能会大大高估LST。与CERC（1984）相比，使用KAMPHIUS（1991）对海滩坡度和波浪周期更为敏感，可能会过度预测具有高波浪能量的陡坡海滩上的输运。岸礁的存在显着影响LST模型的能力，以准确地预测泥沙输运。在应用CERC（1984年，1991年）和KAMPHIUS（1991年）公式时，假定可用于沉积物输运的功能海滩剖面面积比Kaanapali的实际面积大得多。没有一个模型评估帐户的存在的珊瑚礁系统。这可能导致对LST的高估，因为它们假设整个剖面是移动的沉积物。然而，CERC（1991年）低估了观测到的输送量，这意味着这些模型中采用的环境参数（如波高、方向和周期）在模型结果中比珊瑚礁的影响发挥更重要的作用。
Longshore sediment transport (LST) measured at monthly beach profiles on Kaanapali Beach, Maui is compared to three predictive models. We observe cumulative net sediment transport rates of approximately 29,379 ±4400 m 3 /yr to the north and 22,358 ±1300 m 3 /yr to the south for summer and winter respectively. Kaanapali Beach experiences a net annual rate of 7,021 ±700 m 3 /yr to the north and a gross annual rate of 51,736 ±5100 m 3 /yr. Transport models, namely CERC (1984), CERC, 1991 (GENESIS) and KAMPHIUS (1991) predict net annual LST rates at 3 × 10 3 percent, 77 percent and 6 × 10 3 percent of the observed rates respectively. The success of the Genesis model is attributed to its ability to account for short-term changes in near-shore parameters. The use of CERC (1984) is prone to practical errors in its application including use of the recommended K coefficient and wave averaging that may significantly overestimate LST. The use of KAMPHIUS (1991) is more sensitive to beach slope and wave period than CERC (1984) and may over-predict transport on steep sloped beaches with high wave energy. Presence of fringing reef significantly affects the ability of LST models to accurately predict sediment transport. When applying CERC (1984, 1991) and KAMPHIUS (1991) formulas, functional beach profile area available for sediment transport is assumed much larger than actually exists in Kaanapali. None of the models evaluated account for the presence of a reef system. This may contribute to overestimations of LST as they assume the entire profile is mobile sediment. However, the fact that CERC (1991) underestimates the observed transport implies that environmental parameters employed in these models (such as wave height, direction and period) play a more substantial role than the influence of the reef in model results.