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  • General

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  • 地下水

    What are these faucets tapping into?
    ::这些水龙头在钻什么?

    This certainly is an odd sight! We expect to see  water  at Earth's surface, but coming out of solid  ? Amazingly, much of Earth's fresh water is hidden from sight. It is present in rock and  soil . In  fact , 20 times more of Earth’s liquid  freshwater  is found below the surface than on the surface.
    ::这的确是一个奇特的景象。 我们期望在地球表面看到水,但水却从固体中流出? 令人惊讶的是,地球大部分淡水都隐藏在看不见的地方。 它存在于岩石和土壤中。 事实上,在地表下发现的地球液体淡水量比在地表上多20倍。

    Groundwater
    ::地下水

    Freshwater below Earth’s surface is called  groundwater . The water infiltrates, or seeps down into, the ground from the surface. How does this happen? And where does the water go?
    ::地表下的淡水被称为地下水。 水从地表渗入或渗入地下。 怎么会发生这种情况? 水流向哪里?

    Porous and Impermeable Rock
    ::易爆和隐含岩

    Water infiltrates the ground because soil and rock may have air spaces between the grains. These pores, or tiny holes, result in the rock's  porosity . If water can move through a rock, the rock is  permeable . Eventually, the water reaches a layer of rock that is not porous. This rock is  impermeable . Water stops moving downward when it reaches an impermeable layer.
    ::水渗入地面是因为土壤和岩石之间可能有空气空间。 这些孔孔或小洞导致岩石的孔隙。 如果水能穿过岩石, 岩石是渗透的。 最终, 水到达一层没有渗入的岩石层。 这块岩石是不可渗透的。 当水到达一个不可渗透的层时, 水停止向下移动 。

    The diagram below ( Figure   ) shows two layers of porous rock. The top layer is not saturated; it is not full of water. The next layer is saturated. The water in this layer has nowhere else to go. It cannot seep any deeper into the ground because the rock below it is impermeable. The saturated layer where water is stored is called an  aquifer .
    ::下面的图表(图)显示两层多孔岩。 顶层没有饱和, 没有满水。 下一层是饱和的。 下一层是饱和的。 此层的水无处可去。 由于下面的岩石是不可渗透的, 它无法在地下深处渗入。 储水的饱和层被称为蓄水层 。

    Groundwater layers, aquifer, water table, well, and impermeable rock.
     
    Water seeps into the ground through permeable material. The water stops when it reaches an impermeable rock. Predict the purpose of the well in the diagram.

    The Water Table
    ::水表

    The top of the saturated rock layer above ( Figure   ) is called the  water table . The water table isn’t like a real table. It doesn’t remain firmly in one place. Instead, it rises or falls, depending on how much water seeps down from the surface. The water table is higher when there is a lot of  rain , and it is lower when the   is dry.
    ::上面饱和岩层的顶部(图)被称为水位。 水位不象一个真实的表。 它不固定在一个地方。 相反,它会上升或下降,取决于从地表向下渗出多少水。 降雨量大时水位更高,干燥时水位较低。

     

    Summary
    ::摘要

    • Water infiltrates into the ground.
      ::水渗入地下
    • There is much more fresh water underground than on the surface.
      ::地下的淡水比地表要多得多。
    • A rock layer must be porous and permeable to be a good aquifer. An impermeable layer makes up the bottom of an aquifer.
      ::岩石层必须多孔、渗透性强,才能成为一个良好的含水层,含水层底部是不可渗透的层。
    • The water table rises and falls with additions or subtractions to the groundwater system.
      ::地下水系统因地下水系统增减而上升和下降。

    Review
    ::回顾

    1. Why does rock or soil need to be permeable for there to be groundwater?
      ::为什么岩石或土壤需要渗透才能有地下水?
    1. How does water become groundwater?
      ::水如何成为地下水?
    1. What happens if there is an impermeable rock layer underground?
      ::如果地下有不可渗透的岩层会怎样?
    1. What can make the water table move up or down?
      ::是什么让水位向上或向下移动?