When the ground become so saturated that water can no longer seep into the soil, it begins to run off quickly into rivers and streams and this causes a rise in water and a flash.

地面被浸透以后，水流就无法渗入土壤中，而是开始迅速流入河流和小溪，这会造成水位上升继而引发暴洪。

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At more than 50%, the ground becomes water-logged and any excess liquid will simply run off.

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