The presence of dunes or antidunes in streams alternately decreases and increases the local depth.

河流中沙垄和逆行沙垄的存在，使局部水深交替地增大或减小。

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The presence of dunes or antidunes in streams alternately decreases and increases the local depth.

河流中沙垄和逆行沙垄的存在，使局部水深交替地增大或减小。

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