High erosion and runoff rates have been measured on road infrastructure, indicating that unpaved roads might be significant sources of sediment in catchments. In this paper, the production of surface sediments from unpaved rural roads is assessed in Northeastern Brazil, in a semiarid area of the caatinga biome, vulnerable to desertification. Sediment production data from road surface segments were monitored for 2 years (2013–2014) under conditions of natural precipitation. By using hydrosedimentological modeling and a geographical information system (GIS), the sediment budget was calculated at the meso-scale catchment (aprox. 930 km²), in order to identify the relative contribution of roads to the sediment balance. The universal soil loss equation (USLE) associated with Maner's sediment delivery ratio (SDR) equation, proved to be an adequate approach for predicting sediment yield on the road segment scale. The best results were obtained for the road without traffic, due to the non-interference in this segment of external factors, such as traffic and maintenance activities, not explicitly considered in the model formulation. The modeling procedure showed that the roads, which occupy only 0.7% of the catchment surface, were responsible for approximately 7% of soil loss in the area. Furthermore, sediment connectivity might be enhanced by roads, which cross the river network and, therefore, deliver more directly the sediment generated at hillslopes. This is particularly important in the studied environment, where sediment connectivity is low due to limited runoff and the existence of a dense network of surface water reservoirs.

中文翻译：

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未铺砌道路在半干旱中尺度流域沉积物收支中的作用

道路基础设施的侵蚀和径流率很高，表明未铺砌的道路可能是集水区沉积物的重要来源。在本文中，对巴西东北部卡廷加生物群落半干旱地区未铺砌的农村道路产生的表层沉积物进行了评估，该地区易受荒漠化影响。在自然降水条件下监测了 2 年（2013-2014 年）来自路面段的沉积物生产数据。通过使用水文沉积学模型和地理信息系统 (GIS)，在中尺度流域（约 930 km ²)，以确定道路对泥沙平衡的相对贡献。与 Maner 的泥沙输送率 (SDR) 方程相关联的通用土壤流失方程 (USLE) 被证明是预测路段规模泥沙产量的适当方法。由于没有在模型制定中明确考虑的外部因素（例如交通和维护活动）不干扰这一部分，因此在没有交通的道路上获得了最佳结果。建模程序表明，仅占集水区表面 0.7% 的道路造成了该地区约 7% 的土壤流失。此外，穿越河流网络的道路可能会增强沉积物的连通性，因此更直接地输送在山坡上产生的沉积物。