In addition to soil losses on hillslopes, unpaved rural roads, especially when poorly designed and maintained, can be a significant contributor to the erosive processes seen at the catchment scale. In areas with deep soils, the solutions primarily focus on channeling excess surface runoff into settling ponds or terraces. However, few studies have addressed runoff control from roads on steep slopes in areas of shallow soil. Modeling hydrological processes at the catchment scale is a useful strategy for choosing the most effective and least costly conservation practices to control surface runoff. This study applies a mathematical model to a monitored catchment in southern Brazil to better understand the effects of conservation practices on unpaved roads and their impact on the hydrological and erosive dynamics of a small rural catchment. We calibrated the LISEM model using data from eight stormwater events and evaluated how three different road conservation scenarios—low (LI), medium (MI), and high intensity (HI)—contributed to sediment yield (SY), surface runoff volume (Qe), and peak flow (Qp) reduction. The LI and MI scenarios involved installation of hydraulic structures to control the road surface runoff (i.e. road ditch graveling, diversion weirs and grass waterways) while the HI scenario added surface runoff control practices (grass strips) to surrounding crop fields, in addition to the practices included in the MI scenario. Based on these scenarios, the results showed a Qe reduction at the catchment outlet from − 3.5% (LI) to − 22.5% (HI). The Qp and SY varied from + 6.0% (LI) to − 292.5% (HI) and from + 20.0% (LI) to − 963.9% (HI), respectively. These results show that the low- and medium-intensity practices were not effective in controlling surface runoff from roads, based on the Qe, Qb, and SY observed at the catchment’s outlet. On the other hand, when MI scenarios were complemented with practices to control surface runoff in the cultivated areas, a significant reduction in surface runoff (Qe and Qp) and SY was verified.

除了山坡上的土壤流失外，未铺砌的农村道路，尤其是在设计和维护不当的情况下，可能是造成流域范围内侵蚀过程的重要因素。在土壤较深的地区，解决方案主要侧重于将多余的地表径流引入沉淀池或梯田。然而，很少有研究涉及浅层土壤地区陡坡道路的径流控制。在流域尺度模拟水文过程是选择最有效和成本最低的保护措施来控制地表径流的有用策略。本研究将数学模型应用于巴西南部受监控的集水区，以更好地了解保护措施对未铺砌道路的影响及其对小型农村集水区的水文和侵蚀动态的影响。我们使用来自八个雨水事件的数据校准了 LISEM 模型，并评估了三种不同的道路保护情景——低 (LI)、中 (MI) 和高强度 (HI)——如何对沉积物产量 (SY)、地表径流体积 (Qe) 做出贡献) 和峰值流量 (Qp) 降低。LI 和 MI 情景涉及安装水工结构以控制路面径流（即道路沟渠碎石、导流堰和草水道），而 HI 情景除了对周围的农田增加地表径流控制措施（草带）之外MI 场景中包含的实践。基于这些情景，结果显示集水口出口 Qe 从 - 3.5% (LI) 减少到 - 22.5% (HI)。Qp 和 SY 分别从 + 6.0% (LI) 到 - 292.5% (HI) 和从 + 20.0% (LI) 到 - 963.9% (HI)。这些结果表明，根据在集水区出口处观察到的 Qe、Qb 和 SY，低强度和中等强度的做法在控制道路地表径流方面没有效果。另一方面，当 MI 情景与控制耕地地表径流的做法相辅相成时，地表径流（Qe 和 Qp）和 SY 的显着减少得到证实。