Ephemeral streams flow only in direct response to precipitation and are ubiquitous landscape features. However, little is known about their influence on downstream rivers. Here, we modeled ephemeral stream water contributions to the contiguous United States network of more than 20 million rivers, lakes, and reservoirs, finding that ephemeral streams contribute, on average, 55% of the discharge exported from regional river systems, as defined by the United States Geological Survey. Our results show that ephemeral connectivity is a substantial pathway through which water and associated nutrients and pollution may enter the perennial drainage network and influence water quality. We provide quantitative insight into the implications of differing interpretations of regulatory jurisdiction under the United States Clean Water Act, including the current standard adopted by the Supreme Court of the United States in 2023.

中文翻译：

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短暂溪流对美国排水网络的贡献


短暂的溪流仅在直接响应降水的情况下流动，是普遍存在的景观特征。然而，人们对它们对下游河流的影响知之甚少。在这里，我们对美国超过 2000 万条河流、湖泊和水库网络中的临时溪流水贡献进行了建模，发现临时溪流平均贡献了区域河流系统排放量的 55%（根据美国地质调查局。我们的研究结果表明，短暂连通性是水和相关营养物质和污染物进入常年排水网络并影响水质的重要途径。我们对《美国清洁水法案》监管管辖权的不同解释的影响提供定量见解，包括美国最高法院于 2023 年采用的现行标准。