A subterraneanflow 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。
2
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.