California has been facing a drought for many years now, with certain areas even having to pump freshwater hundreds of miles to their distribution system. The problem is growing as the population of the state continues to expand. New research has found deep water reserves under the state which could help solve their drought crisis. Previous drilling of wells could only reach depths of 1,000 feet, but due to new pumping practices, water deeper than this can now be extracted (抽取). The team at Stanford investigated the aquifers (地下蓄水层) below this depth and found that reserves may be triple what was previously thought.

    It is profitable to drill to depths more than 1,000 feet for oil and gas extraction, but only recently in California has it become profitable to pump water from this depth. 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. The biggest concern of pumping out water from this deep in the gradual settling down of the land surface. As the water is pumped out, the vacant space left is compacted by the weight of the earth above.

    Even though pumping from these depths is expensive, it is still cheaper than desalinating (脱盐) the ocean water in the largely coastal state. Some desalination plants exist where feasible, but they are costly to run and can need constant repairs. Wells are much more reliable sources of freshwater, and California is hoping that these deep wells may be the answer to their severe water shortage.

    One problem with these sources is that the deep water also has a higher level of salt than shallower aquifers. This means that some wells may even need to undergo desalination after extraction, thus increasing the cost. Research from the exhaustive study of groundwater from over 950 drilling logs has just been published. New estimates of the water reserves now go up to 2,700 billion cubic meters of freshwater.

B。根据题干中的extracting water from deep aquifers和顺序原则可定位至文章第二段，该段首句提到，直到最近，在加利福尼亚州从超过1000英尺深的蓄水层抽水才变得颇为盈利。由此可推断，在此之前人们认为这样做是不盈利的，也就是说不值得花这笔钱从1000英尺深的蓄水层抽水，故正确答案为B。原文中虽然说到抽取深层水可以帮助解决干旱问题，但并未表明这就是解决缺水问题的关键，故A项错误。文章最后一段指出深层水的含盐量比浅层水要高，但随后也说到需要对这些水进行淡化处理，并不能说明这种方式无法提供优质淡水，故C项错误。D项中的be bound to表示“一定”，说法过于绝对，故排除D项。