Land use changes in many landscapes result in gully formation, carving up agricultural land and playing a large role in filling up downstream reservoirs by connecting uplands with rivers. This includes the Ethiopian highlands. Our objective is to begin investigating the interaction of upland and gully erosion and to quantify the portion of eroded sediment originating from a gully to prioritize erosion control practices. For this purpose, a 5‐m deep valley bottom gully of the 13‐ha catchment in the Debre Mawi watershed in the subhumid Ethiopian highland near Lake Tana was selected. The upstream and downstream gully discharge and sediment concentrations were measured over a 2‐year period. The results show that the sediment concentration at the outlet was about 10 times greater than at the inlet. The sediment budget calculation showed that about over 90% of the sediment at the outlet originated from within the gully. Hysteresis analysis of the sediment concentration discharge relationship showed that sediment supply from the upland was limited, but sediment was always available to be eroded and transported in the gully because of bank failures and headcut retreat. Thus, to reduce sediment loads in rivers and consequent adverse downstream impacts, designing cost‐effective measures to treat gullies should be a priority in the subhumid Ethiopian highlands.

中文翻译：

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沟壑是景观土壤流失的关键环节：以埃塞俄比亚半湿润高原为例

在许多景观中，土地利用的变化导致了沟壑的形成，割裂了农业用地，并在通过连接高地和河流的方式来填充下游水库中发挥了重要作用。这包括埃塞俄比亚高地。我们的目标是开始调查山地和沟壑侵蚀的相互作用，并量化源自沟壑的侵蚀性沉积物部分，以优先进行侵蚀控制。为此，在塔纳湖附近亚湿润的埃塞俄比亚高地的德布雷马维流域的13公顷流域选择了一个5米深的谷底沟。在两年的时间内测量了上游和下游的沟渠排放量和沉积物浓度。结果表明，出口处的沉积物浓度比入口处高约10倍。泥沙预算计算表明，出口处约90％的泥沙来自沟渠内部。泥沙浓度-流量关系的滞后分析表明，来自山地的泥沙供应有限，但由于堤岸破坏和前冲后撤，泥沙始终可以在沟渠中侵蚀和运输。因此，为减少河流中的泥沙负荷和随之而来的不利下游影响，在亚湿润的埃塞俄比亚高地，设计具有成本效益的措施来处理沟渠应成为优先事项。但是由于堤岸的倒塌和顶撤的影响，沉积物总是可以在沟渠中被侵蚀和运输。因此，为减少河流中的泥沙负荷和随之而来的不利下游影响，在亚湿润的埃塞俄比亚高地，设计具有成本效益的措施来处理沟渠应成为优先事项。但是由于堤岸的倒塌和顶撤的影响，沉积物总是可以在沟渠中被侵蚀和运输。因此，为减少河流中的泥沙负荷和随之而来的不利下游影响，在亚湿润的埃塞俄比亚高地，设计具有成本效益的措施来处理沟渠应成为优先事项。