A subterranean flow of briny water could rearrange sand grains or alter surface roughness in a way that darkens its appearance.

地下水流的流动会使得沙粒积累，并使得表面变得粗糙，从而颜色更深。

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Contribution percentages about precipitation to runoff were calculated to divide rapid flow and slow flow in the model, the proportion of them of Wuyandong subterranean stream system is 2 to 3.

通过降水对径流的贡献率进行快速流和慢速流的划分，屋檐洞地下河系统的快速流与慢速流比例接近2∶3。

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