河川デルタ形態学:波の気候と水下プロファイルの役割

L D Wright, J M Coleman

Science (New York, N.Y.)

|April 21, 1972

まとめ

デルタ地帯の地形は,沿岸の波動力と河川の排水によって形作られています. 地下水面の斜面と沈殿物の供給の影響を受ける近岸波のエネルギーは,川や波の力が沿岸の形態学を支配するかどうかを決定する.

科学分野:

ジオモルフォロジージオモルフォロジー
海洋学海洋学海洋学
堆積物学堆積物学堆積物学堆積物学堆積物学

背景:

デルタ海域の海岸線は,多様な地形構造を示しています.
河川と海の過程の相互作用を理解することは,沿岸研究において極めて重要です.

研究の目的:

波の気候,河川の排水,デルタの地形形成の発達との関係を調査する.
岸付近の波力を制御する要因と,その影響が沿岸の形態学に及ぼす影響を決定する.

主な方法:

7つの主要なデルタに包括的な波の気候プログラムを適用しました.
深水と近岸の波動力の相関を分析した.
水中の斜面,大陸棚の特徴,河川の堆積物供給の影響を評価した.

主要な成果:

デルタ形状は,近岸の波力や相対的な河川流出によって大きく影響を受けます.
近岸波動力は,主に水下斜面の関数であり,深海波動力の関数ではありません.
水下傾きは,大陸棚の特性によって決定され,重要なことに,河川の堆積物供給率によって決定されます.

結論:

川が平坦な沖合プロフィールを形成し,近岸の波のエネルギーを減少させると,川が支配するデルタ的な地形が形成されます.
波が支配する沿岸の地形が優勢で,急な水中の斜面が波の力を減らすことなく海岸に到達することを可能にします.
堆積物供給率は,水下斜面の主要な制御であり,その結果,沿岸の地形学です.

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