ABSTRACT Surface runoff generation capacity can be modified by land-use and climate changes. Annual runoff volumes have been evaluated in a small watershed of tropical forest (Brazil), using the Soil and Water Assessment Tool (SWAT) model. Firstly, the accuracy of SWAT in runoff predictions has been assessed by default input parameters and improved by automatic calibration, using 20-year observations. Then, the hydrological response under land uses (cropland, pasture and deforested soil) alternative to tropical forest and climate change scenarios has been simulated. SWAT application has showed that, if forest was replaced by crops or pasture, the watershed’s hydrological response would not significantly be affected. Conversely, a complete deforestation would slightly increase its runoff generation capacity. Under forecasted climate scenarios, the runoff generation capacity of the watershed will tend to decrease and will not be noticeably different among the representative concentration pathways. Pasture and bare soil will give the lowest and highest runoff coefficients, respectively.

中文翻译：

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土地利用和气候变化对热带森林流域地表径流的影响（巴西）

摘要 土地利用和气候变化可以改变地表径流产生能力。使用土壤和水评估工具 (SWAT) 模型在热带森林（巴西）的一个小流域中评估了年径流量。首先，SWAT 在径流预测中的准确性已通过默认输入参数进行评估，并通过使用 20 年观测的自动校准进行了改进。然后，模拟了替代热带森林和气候变化情景的土地利用（农田、牧场和森林砍伐的土壤）下的水文响应。SWAT 应用表明，如果森林被农作物或牧场所取代，流域的水文响应不会受到显着影响。相反，完全砍伐森林会略微增加其径流产生能力。在预测的气候情景下，流域的径流生成能力将趋于下降，并且在代表性的集中路径之间不会有明显差异。牧场和裸土将分别给出最低和最高的径流系数。