《汉书·志·五行志上》
那样，黑水暴发，江河泛滥，冲坏城乡，淹死人民，以及淫雨连绵，伤害庄稼，这就是水不润下。
雾水暴出，百川逆溢，坏乡邑，溺人民，及淫雨伤稼穑，是为水不润下。
In that case, black water will erupt, rivers and streams will flood, ruin cities and towns, drown people, and cause endless torrential rain damage to crops. This is what it means for water not to moisten downward.