庙岛南部海域海砂开采对海底地形的影响
INFLUENCE OF MARINE AGGREGATES MINING ON SUBMARINE TOPOGRAPHY OFF SOUTH MIAODAO
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摘要: 利用庙岛南部海域海砂开采区海底地形实测资料,对比分析了海砂开采过程中历年来海底地形地貌的特征变化,发现采砂活动并未引起该区水深发生较大变化。由于动态补偿作用,采砂以后在潮流和波浪的共同作用下,周围海域的泥沙将不断向采砂导致的深槽内填充,并使深槽逐渐变浅。输沙量计算结果表明,长岛海域净供砂量为9.0×104 m3/a。从输沙方向看与潮流和波浪的影响及海底地形的走向密切相关。目前开采量小于3.3×104 m3/a,如果按照目前采砂规模,保证安全生产,采砂工程不会对海底地形、海岸地貌造成明显的影响。Abstract: A comparative study on the change in submarine topography and geomorphology is made for the marine aggregate mining area to the south of Miaodao with the measured data in the past years. It is found that the mining of marine aggregates has not changed much of the water depth of this area, because of dynamic compensation. Sands from nearby regions brought by tide and wave to the area is enough to fill or partly fill the deep notches caused by submarine mining. Calculation of sediment budget shows that the net input of sands into the offshore Changdao island is 9.0×104 m3/a and the current production of marine aggregate is less than 3.3×104 m3/a. If the production of marine aggregates remains on this level, the exploitation of marine aggregates will not bring noticeable effects on submarine topography and coastal landform.