It's a vast water supply,

这是个巨大供水源
and used to a great extent to fuel the agriculture industry in this part of the country.

并被广泛用于美国相关地区的农业生产
It's a major agricultural resource but it's considered to be

作为主要的农业资源
--it's projected to be unusable in a period of twenty years.

二十年后该资源便会被消耗殆尽
What does that mean?

这意味着什么
Well it means that the local water resource is depleted,

这意味着当地的水资源已经耗尽
so to the extent that these farmers can get water that's relatively local--

甚至于农民本来可以从当地获得水资源
although nothing is local, it's not like each farmer has a well

因为已经没有水也不是每个农民
that goes into this aquifer and water is pumped there,

都有深达蓄水层的井水可用
it's still transported some distance--

这就需要远距运输水
but it means water will have to come in from some other place.

意味着不得不从其他地方弄水
Well where is that other place, and

其他地方的水井