Groundwater level records in North America are relatively short (<60 years), preventing long-term analysis of historical changes in groundwater levels associated with drought. In this study, tree ring widths are used to reconstruct groundwater levels in three regions in the North American Cordillera: Central British Columbia (BC), Canada, the Southern Interior Region of BC, and the San Luis Valley in Colorado, USA. Periods with severe drought conditions, identified using regime shift and threshold analyses were: 1890–1900 and 1950–1970 in Colorado, around 1920–1940 in the BC Interior, and 1935–1945 in Central BC. The groundwater level reconstructions are correlated with several climate indices and have similar regime shifts as identified in streamflow and drought records. The groundwater level reconstructions are strongly related to winter snowpack, suggesting that the observed trend of declining snowpack in recent years may lead to declining groundwater availability in these regions.

中文翻译：

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北美科迪勒拉山脉过去的地下水干旱


北美的地下水位记录相对较短（<60 年），因此无法对与干旱相关的地下水位历史变化进行长期分析。在这项研究中，树木年轮宽度用于重建北美科迪勒拉山脉三个地区的地下水位：加拿大不列颠哥伦比亚省中部 （BC）、不列颠哥伦比亚省南部内陆地区和美国科罗拉多州的圣路易斯河谷。使用制度偏移和阈值分析确定的严重干旱时期为：科罗拉多州的 1890-1900 年和 1950-1970 年，不列颠哥伦比亚省内陆的 1920-1940 年左右，以及不列颠哥伦比亚省中部的 1935-1945 年。地下水位重建与几个气候指数相关，并且具有与溪流和干旱记录中确定的类似的状况变化。地下水位重建与冬季积雪密切相关，这表明近年来观察到的积雪减少趋势可能导致这些地区地下水供应量下降。