Sediment transport in rivers is not steady through time. Highly intermittent river systems, which only transport bedload during the most significant flow events, are particularly sensitive to changes in climate and precipitation patterns. People and landscapes can be vulnerable to fluvial processes, and quantifying river intermittency is critical for assessing landscape response to projected changes in precipitation extremes due to climate change. We generated new constraints on recent to modern fluvial intermittency factors—the frequency at which bedload is mobilized in a river—based on field measurements in the Corinth Rift, Greece, and Holocene sediment accumulation rates. Results reveal some of the lowest documented intermittency factors to date, showing Mediterranean rivers can transport an entire annual sediment load in a rare storm event. Coupling intermittency calculations with historical flood and precipitation data indicates these rivers transport bedload during one storm every ~4 yr, associated with rainfall >50 mm/d, and subsequent floods; this hydroclimate is typical across the Mediterranean region. Furthermore, climate models predict precipitation extremes will increase across Europe, and the frequency of events that surpass thresholds of sediment transport will increase significantly, potentially causing sediment loads to double by 2100 CE. As the area of arid land likely to host intermittent rivers also increases, sensitive landscapes are on the edge of significant geomorphic change, driven by global warming.

中文翻译：

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边缘景观：变暖世界中的河流间歇性


随着时间的推移，河流中的泥沙输送并不稳定。高度间歇性的河流系统仅在最重要的水流事件期间输送床质，对气候和降水模式的变化特别敏感。人和景观可能容易受到河流过程的影响，量化河流间歇性对于评估景观对气候变化导致的极端降水预计变化的响应至关重要。我们根据希腊科林斯裂谷和全新世沉积物积累率的现场测量，对近现代河流间歇性因素（河流中床载流动的频率）产生了新的约束。结果揭示了迄今为止有记录的一些最低的间歇性因素，表明地中海河流可以在罕见的风暴事件中输送整个年度沉积物负荷。将间歇性计算与历史洪水和降水数据相结合表明，这些河流在每约 4 年一场风暴期间输送河床负荷，与降雨量 >50 毫米/天以及随后的洪水相关；这种水文气候在整个地中海地区都很常见。此外，气候模型预测欧洲各地的极端降水量将增加，超过沉积物输送阈值的事件频率将显着增加，可能导致沉积物负荷在公元 2100 年增加一倍。由于可能存在间歇性河流的干旱土地面积也在增加，全球变暖导致敏感景观处于显着地貌变化的边缘。