2003到2013年间加利福尼亚大学所研究的37个最大规模蓄水层中有1/3已经严重干涸，而且几乎或根本得不到降雨的补充。
And one-third of the 37 largest aquifers studied by the University of California between 2003 and 2013 were severely depleted, receiving little or no replenishment from rainfall.