Winter/spring runoff has changed in streams worldwide due to climate change, particularly in temperate areas where winter/spring streamflow depends on snowmelt. Such changes potentially affect receiving waters through altered nutrient loading and mixing patterns. The Laurentian Great Lakes are an important freshwater resource and have experienced a myriad of impacts due to climate change. We analyzed 70 years of stream gauge data in the Great Lakes Basin to test for changes in timing, duration, and amount of winter/spring runoff during the period 1950–2019. We found strong evidence for earlier runoff in each of the Great Lakes except Lake Erie, protracted winter/spring runoff throughout the Great Lakes Basin, and a higher runoff depth during the winter-spring period over time for all watersheds except Lake Superior. Lake Ontario had the greatest change in the date by which 50% of the Jan–May runoff had been discharged (6 days earlier from 1950 to 2019). For winter/spring runoff duration, the most extreme change was observed in Lake Erie (increase of 19 days), and for runoff depth, the greatest change was in the Lake Huron Basin (increase of 3.3 cm). Results were similar for natural and impacted streams. Our results demonstrate dramatic changes in runoff patterns over the last seven decades in the Great Lakes Basin concomitant with previously published changes in precipitation and snowpack. Shifts toward earlier, more protracted, and more voluminous runoff likely change nutrient loading and mixing patterns that influence primary producers, particularly in the nearshore areas of the Great Lakes.

中文翻译：

---

劳伦森五大湖盆地的冬/春季径流更早、更持久且水量增加

由于气候变化，全世界河流的冬/春季径流发生了变化，特别是在冬/春季径流依赖于融雪的温带地区。这些变化可能会通过改变养分负荷和混合模式来影响受纳水域。劳伦森五大湖是重要的淡水资源，并经历了气候变化带来的诸多影响。我们分析了五大湖流域 70 年的流量计数据，以测试 1950 年至 2019 年期间冬/春季径流的时间、持续时间和量的变化。我们发现强有力的证据表明，除伊利湖外，五大湖的径流较早，整个五大湖盆地的冬/春季径流持续时间较长，而且除苏必利尔湖外，所有流域在冬春季节期间径流深度都较高。安大略湖 1 月至 5 月径流 50% 排出的日期变化最大（1950 年至 2019 年提前了 6 天）。对于冬/春季径流持续时间，变化最极端的是伊利湖（增加了19天），径流深度变化最大的是休伦湖盆地（增加了3.3厘米）。自然溪流和受影响溪流的结果相似。我们的结果表明，过去七十年中五大湖盆地的径流模式发生了巨大变化，同时也伴随着之前公布的降水和积雪的变化。径流向更早、更持久、更大量的转变可能会改变影响初级生产者的养分负荷和混合模式，特别是在五大湖近岸地区。