Hilton Annette, Jasechko Scott
Bren School of Environmental Science and Management, University of California, Santa Barbara, CA 93106, USA.
Sci Adv. 2023 Sep 15;9(37):eadh2992. doi: 10.1126/sciadv.adh2992. Epub 2023 Sep 13.
Water supplies for household use and irrigated agriculture rely on groundwater wells. When wells are drilled into a highly pressurized aquifer, groundwater may flow up the well and onto the land surface without pumping. These flowing artesian wells were common in the early 1900s in the United States before intensive groundwater withdrawals began, but their present-day prevalence remains unknown. Here, we compile and analyze ten thousand well water observations made more than a century ago. We show that flowing artesian conditions characterized ~61% of wells tapping confined aquifers before 1910, but only ~4% of wells tapping confined aquifers today. This pervasive loss of flowing artesian conditions evidences a widespread depressurization of confined aquifers after a century of intensive groundwater use in the United States. We conclude that this depressurization of confined aquifers has profoundly changed groundwater storage and flow, increasing the vulnerability of deep aquifers to pollutants and contributing to land subsidence.
家庭用水和灌溉农业的供水依赖于地下水井。当水井钻至高压含水层时，地下水可能无需抽水就会顺着水井向上流到地表。在20世纪初美国开始大量抽取地下水之前，这些自流井很常见，但它们如今的普遍程度仍不为人知。在这里，我们汇编并分析了一个多世纪前的一万份井水观测数据。我们发现，在1910年之前，自流条件在约61%的开采承压含水层的水井中存在，但如今开采承压含水层的水井中只有约4%具备自流条件。自流条件的这种普遍丧失表明，在美国经过一个世纪的大量地下水开采后，承压含水层普遍出现了减压现象。我们得出结论，承压含水层的这种减压现象已深刻改变了地下水的储存和流动，增加了深层含水层对污染物的脆弱性，并导致了地面沉降。
