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。

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。

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。

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。

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。

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。

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。

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。

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。

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。

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

大多数石灰岩和砂岩的蓄水层很深并且规模很大，但是它们含有的地下水可能是当前无法再生的。

The mineral content of groundwater normally increases with the depth, but even quite shallow aquifers can be highly saline.

地下水的矿物含量通常随深度的增加而增加，但即使很浅的蓄水层中可能含盐量也很高。

The team at Stanford investigated the aquifers below this depth and found that reserves may be triple what was previously thought.

斯坦福大学的研究小组对这一深度以下的地下蓄水层进行了调查，发现蓄水量或许是先前所预想的三倍。

Groundwater aquifers are being pumped down faster than they are naturally replenished in parts of India, China, the USA and elsewhere.

在印度、中国、美国等地，地下含水层被抽离的速度比自然补给还要快。

Farmers are draining the aquifers.

农民在抽取地下水。

And about 280 aquifers also cross borders.

而且约有280个地下蓄水层横跨国界。

The pipeline route crosses rich farmland and important aquifers.

输油管线沿途经过富饶农田和重要的蓄水层。

Just as serious is the depletion of the aquifers on which farmers depend.

农民们脚下的含水层损耗同样严重。

The highlands are main recharge area for Israel "s coastal aquifers."

高地是防止以色列海岸进攻的主要防御工事。

Depletion of aquifers is a looming tragedy. New agreements offer hope.

含水层的干涸已成为迫在眉睫的危机，新的协议给了我们希望。

Much of Yemen's water is mined from rapidly depleting underground aquifers.

也门的大部分用水都是从快速耗竭的地下蓄水层中开采的。

In Bangladesh, where some 70 million people are exposed, the use of deep aquifers is a more recent phenomenon.

在孟加拉国，大约7000万人受到侵害，使用深层地下水是一个较近期的现象。

Cities there function like space stations, importing every ounce of fresh water from distant rivers or fossil aquifers.

那里的城市似乎成了空间站，从遥远的河流或者“化石”蓄水层提取每一滴淡水。

Having drained underground aquifers to grow inappropriate crops for many years, they have turned en masse to desalination.

在经过多年抽取地下水用于灌溉并不合适的庄稼后，他们开始进行海水淡化。

Experts are still refining the count: the American-Mexico border may include 8, 10, 18 or 20 aquifers, depending on how you measure them.

专家们仍然在推敲总数：根据不同的测量方式，美墨边境可能有8、10、18或20处含水层。

Tens of millions of smallholders have invested in their own pumps so that they can extract water from shallow aquifers whenever they choose.

上千万的小农户自己出资买水泵，以便随时从浅表水层中抽水。

Aquifers full of brine, however, could be better because there are so many of them, and they often lie close to offshore oil - and gas-fields.

但是，把这种方法应用到充满盐水的蓄水层可获得更好的效果，因为这样的蓄水层不仅数量多，而且它们通常位于海岸的油气田附近。