The Columbia River in the us Northwest lost about 14 percent of its volume from 1948 to 2004, largely because of reduced precipitation and higher water usage in the west.

在1948年至2004年间，位于美国西北部地区的哥伦比亚河的流量减少了约14%，这主要是由于降水量减少以及美国西部用水量增加。

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As the density of larvae was reduced, the volume of water in the rearing chamber was decreased by lifting it up, keeping the water line above the bottom of the rearing chamber.

当幼虫的密度是不断减少，在繁育间内的水通过提起圆筒而减少，保持水线在繁育间底部上。

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The volume quality of top soil is increased and the soil porosity is reduced owing to compaction, so water flow downward difficultly and the amount of water vertical infiltration is reduced.

由于压实，增加了表层土壤的体积质量，降低了土壤孔隙度，水不易向下运动。

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