The last hydrometeorological extreme event that caused large floods in the southern Atacama Desert in March 2015 raised concern about how little was known about the fluvial dynamic of these arid basins. Understanding the response of intermittent and ephemeral rivers in drylands to the present context of global change is critical to preserve the ecological and human systems they support, to sustainably manage their scarce water resources and to develop flood risk management plans. We have studied the instrumental and historical record and explored the potential of the Copiapó River geological record in the comprehension of how extraordinary the 2015 flood was and how its fluvial dynamic relates with global climate oscillations. We have identified 36 flood events that have occurred in the last 400 years: 22 of them have been classified as ordinary rises of the river flow (discharges <30 m/s), 11 as extraordinary floods in which the damage is confined to areas adjacent to the river (discharges 30–180 m/s), and only 3 as catastrophic floods (discharges >180 m/s), including the 2015 flood event. The incorporation of the historical and palaeohydrological data into the flood frequency analysis results in an increase of the magnitude of the flood quantiles in which large flood events occur with an average recurrence interval of 120 years. Most of the flood events were caused by heavy rains that are largely linked to the Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation with a superimposed effect of the ENSO. Discharges >30 m/s, i.e., extraordinary and catastrophic floods, occur with positive phases of the PDO and the ENSO. Further exploration of the fluvial geological record of the Copiapó River will help lengthening to thousands of years the flood record what will help improving communities' resilience by anticipating flood hazards in the current global change context, in which stronger rainfall events modulated by ENSO and ENSO-like conditions are expected.

中文翻译：

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阿塔卡马沙漠南缘的历史性灾难性洪水：科皮亚波河极端事件的多档案重建

2015 年 3 月，最后一次水文气象极端事件在阿塔卡马沙漠南部引发了大洪水，引发了人们对这些干旱盆地河流动态知之甚少的担忧。了解旱地间歇性和短暂性河流对当前全球变化背景的反应对于保护它们所支持的生态和人类系统、可持续地管理其稀缺水资源以及制定洪水风险管理计划至关重要。我们研究了仪器记录和历史记录，并探索了科皮亚波河地质记录在理解 2015 年洪水的非同寻常及其河流动态与全球气候振荡之间的关系方面的潜力。我们已经确定了过去 400 年来发生的 36 起洪水事件：其中 22 起被归类为普通河水上涨（流量 <30 m/s），11 起被归类为特大洪水，其中损害仅限于邻近地区到河流（流量 30-180 m/s），只有 3 次为特大洪水（流量 >180 m/s），包括 2015 年的洪水事件。将历史和古水文数据纳入洪水频率分析中，导致平均复发间隔为 120 年的大型洪水事件发生的洪水分位数的大小增加。大多数洪水事件是由暴雨引起的，这在很大程度上与太平洋年代际涛动和大西洋数十年涛动以及厄尔尼诺南方涛动的叠加效应有关。流量 >30 m/s，即异常和灾难性洪水，发生在 PDO 和 ENSO 的正相位期间。对科皮亚波河河流地质记录的进一步探索将有助于将洪水记录延长至数千年，这将有助于通过预测当前全球变化背景下的洪水危害来提高社区的抵御能力，其中ENSO和ENSO-调节的更强降雨事件预计会出现类似的情况。