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1·These aquifers became saturated more than 10,000 years ago and are no longer being recharged.

这些含水层在一万多年前就饱和了，现在不再重新补充水分了。

2·Sandstones generally make good aquifers, while finer-grained mudstones are typically impermeable.

砂岩通常是良好的含水层，而细粒泥岩通常是不透水的。

3·Water does not remain immobile in an aquifer but can seep out at springs or leak into other aquifers.

水在含水层中并不是静止不动的，而是会从泉水中渗出，或渗入其他含水层。

4·Beneath the Sahara are huge aquifers, basically a sea of fresh water, that's perhaps a million years old filtered through rock layers.

撒哈拉沙漠下面是巨大的含水层，基本上是一片淡水的海洋，那可能是经过岩石层过滤的，已经有一百万年历史。

5·The aquifers range from 1,000 to 3,000 feet below the ground, which means that pumping will be expensive and there are other concerns.

地下含水层位于地下1000到3000英尺之间，这意味着抽水成本很高，还有其他接踵而来的问题。

6·Anyway, it's this fossilized pollen along with the aquifers and the rock paintings, these three things are all evidence that the Sahara was once much greener than it is today.

总之，这些花粉化石，还有含水层和岩画，这三样东西都证明了撒哈拉沙漠曾经比现在绿得多。

7·Although population, industrial output and economic productivity have continued to soar in developed nations, the rate at which people withdraw water from aquifers, rivers and lakes has slowed.

尽管发达国家的人口、工业产出和经济生产率还在飙升，但人们从含水层、河流和湖泊取水的速度已经放缓。

8·Most shallow aquifers in sand and gravel deposits produce lower yields, but they can be rapidly recharged.

大多数沙石中较浅的蓄水层贮水量少，但可以迅速再生。

9·One problem with these sources is that the deep water also has a higher level of salt than shallower aquifers.

这些水源的一个问题是，深水区的含盐量也比浅水层的含盐量高。

10·Most limestone and sandstone aquifers are deep and extensive but may contain groundwaters that are not being recharged.

大部分的石灰岩和砂岩的蓄水层都是深而广的，但可能含有不可再生的地下水。

含水层

1·These aquifers became saturated more than 10,000 years ago and are no longer being recharged.

这些含水层在一万多年前就饱和了，现在不再重新补充水分了。

2·Sandstones generally make good aquifers, while finer-grained mudstones are typically impermeable.

砂岩通常是良好的含水层，而细粒泥岩通常是不透水的。

3·Water does not remain immobile in an aquifer but can seep out at springs or leak into other aquifers.

水在含水层中并不是静止不动的，而是会从泉水中渗出，或渗入其他含水层。

4·Beneath the Sahara are huge aquifers, basically a sea of fresh water, that's perhaps a million years old filtered through rock layers.

撒哈拉沙漠下面是巨大的含水层，基本上是一片淡水的海洋，那可能是经过岩石层过滤的，已经有一百万年历史。

5·Anyway, it's this fossilized pollen along with the aquifers and the rock paintings, these three things are all evidence that the Sahara was once much greener than it is today.

总之，这些花粉化石，还有含水层和岩画，这三样东西都证明了撒哈拉沙漠曾经比现在绿得多。

(1)confined aquifer承压含水层；被封含水层

(1)unconfined aquifer非承压含水层；不受压含水层；无压含水层