The demand for freshwater resources and climate change pose a simultaneous threat to rivers. Those impacts are often analyzed separately, and some human impacts are widely evaluated in river dynamics—especially in downstream areas rather than the consequences of land cover changes in headwater reaches. The distinction between anthropogenic and climate on the components of the flow regime is proposed here for an upstream free dam reach whose watershed is responsible for the water supply in Rio de Janeiro. Indicators of hydrologic alteration (IHA) and the range of variability approach (RVA) combined with statistical analyses of anthropogenic and climate parameters indicated that (1) four river flow components (magnitude, frequency, duration, and rate of change) were greatly altered from the previous period (1947 to 1967) and the actual (1994 to 2014); (2) shifts in the sea surface temperature of the Atlantic correlated with flow magnitude; (3) the cattle activity effects on the flow regime of the studied area decreased 42.6% of superficial discharge; global climate change led to a 10.8% reduction in the same river component. This research indicated that climate change will impact the intensification of human actions on rivers in the southeast Brazilian headwaters.

中文翻译：

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人为和气候对自由大坝热带河流的影响：测量对流量制度的贡献

对淡水资源的需求和气候变化同时对河流构成威胁。这些影响通常单独分析，一些人类影响在河流动态中得到广泛评估——尤其是在下游地区，而不是上游河段土地覆盖变化的后果。此处针对上游自由水坝河段提出了人为和气候在流态组成部分之间的区别，其流域负责里约热内卢的供水。水文变化指标 (IHA) 和变异范围法 (RVA) 结合人为和气候参数的统计分析表明 (1) 四个河流流量分量（大小、频率、持续时间、和变化率）与上一时期（1947 年至 1967 年）和实际时期（1994 年至 2014 年）相比发生了很大变化；(2) 大西洋海面温度的变化与流量大小相关；(3)牛活动对研究区流态的影响减少了42.6%的表面流量；全球气候变化导致同一河流成分减少了 10.8%。这项研究表明，气候变化将影响巴西东南部源头河流中人类活动的加剧。