MODELING OVERWASH VULNERABILITY ALONG MIXED SAND-GRAVEL COASTS WITH XBEACH-G CASE STUDY OF PLAYA GRANADA, SOUTHERN SPAIN
MODELING OVERWASH VULNERABILITY ALONG MIXED SAND-GRAVEL COASTS WITH XBEACH-G CASE STUDY OF PLAYA GRANADA, SOUTHERN SPAIN
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DOI：
10.9753/icce.v35.sediment.13
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
R. Bergillos;G. Masselink;R. McCall;M. Ortega-Sánchez
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作者：
R. Bergillos;G. Masselink;R. McCall;M. Ortega-Sánchez
这项工作旨在校准混合沙砾三角洲海岸（西班牙南部的普拉亚格拉纳达）的XBeach-G模型，并将其应用于解决过度冲刷的脆弱性。在两次极端西南风暴前后进行了实地调查，包括在两个选定地区进行地形测量和沉积物取样。校准的波浪传播模型（Delft3D-WAVE）用于获得驱动XBeach-G模型所需的近岸条件。粗砾石组分的XBeach-G结果、沉积物摩擦系数为0.03和尼尔森边界层相位滞后为2000，与观测到的海滩剖面形态变化最吻合。这表明海滩的形态动力学响应主要是由粗砾砾组分主导的，这与之前在研究场地进行的实验和数值工作相一致。得到的brier技能分数和均方根误差分别大于0.89和小于0.18 m，表明XBeach-G模型能够再现西南风暴条件下的廓线响应。该模型用于计算产生过冲所需的水位，作为波浪高度和方向的函数，结果显示了XBeach-G的应用如何用于解决砾石为主的海岸上风暴引起的海岸脆弱性问题。
This work aims to calibrate the XBeach-G model on a mixed sand-gravel deltaic coast (Playa Granada, southern Spain) and apply it to address the overwash vulnerability. Field surveys, consisting of topographical measurements and sediment sampling in two selected areas, were performed before and after two extreme southwesterly storms. A calibrated wave propagation model (Delft3D-WAVE) was used to obtain the inshore conditions required to drive the XBeach-G model. The XBeach-G results for the coarse gravel fraction, a sediment friction factor of 0.03 and a Nielsen's boundary layer phase lag of 20o were found to provide the best fits to the observed morphological changes of the beach profile. This indicates that the morphodynamic response of the beach is dominated by the coarse gravel fraction, which is in agreement with previous experimental and numerical works carried out in the study site. The obtained brier skill scores and root-mean-square errors were higher than 0.89 and lower than 0.18 m, respectively, highlighting that the XBeach-G model is capable of reproducing the profile response under southwesterly storm conditions. The model was used to compute the required water level to generate overwash as a function of the wave height and direction, and results show how the application of XBeach-G can be used to address issues of storm-induced coastal vulnerability on gravel-dominated coasts.