To tackle the problem of soil erosion and moisture stress, the government of Ethiopia introduced a yearly mass campaign where communities get together and implement various soil and water conservation (SWC) and water harvesting (WH) practices. Although the interventions are believed to have reduced soil erosion/sediment yield and enhanced surface and ground water, quantitative information on the impacts of various options at different scales is scarce. The objective of this study was to assess the impacts different land uses, SWC and WH interventions on water and suspended sediment yield (SSY) at plot and watershed scales in the central highlands of Ethiopia. Standard erosion plot experiments and hydrological stations were used to monitor the daily water and SSY during 2014 to 2017. The results show differences between treatments both at plot and watershed scales. Runoff and soil loss were reduced by an average 27 and 37%, respectively due to SWC practices at the plot level. Overall, SWC practices implemented at the watershed level reduced sediment yield by about 74% (in the year 2014), although the magnitude of sediment reduction due to the SWC interventions reduced over time. At both scales it was observed that as the number of years since SWC measures have been in place increased, their effectiveness declined due to the lack of maintenance. This study also revealed that extrapolating of plot data to watershed scale causes over or under estimation of net erosion.

中文翻译：

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评估不同土地利用和水土保持干预措施对埃塞俄比亚中部高地不同尺度径流和产沙量的影响

为了解决水土流失和水分胁迫的问题，埃塞俄比亚政府推出了一项年度群众运动，社区聚集在一起，实施各种水土保持 (SWC) 和集水 (WH) 做法。尽管人们认为这些干预措施减少了土壤侵蚀/沉积物产量并增加了地表水和地下水，但关于不同规模的各种选择的影响的定量信息却很少。本研究的目的是评估不同土地利用、SWC 和 WH 干预对埃塞俄比亚中部高地地块和流域规模的水和悬浮泥沙产量 (SSY) 的影响。2014-2017年利用标准侵蚀图实验和水文站监测日水量和SSY。结果显示了小区和流域尺度上的处理之间的差异。由于地块一级的 SWC 做法，径流和土壤流失分别平均减少了 27% 和 37%。总体而言，在流域层面实施的 SWC 实践减少了约 74% 的产沙量（2014 年），尽管由于 SWC 干预导致的沉积物减少幅度随着时间的推移而减少。在这两个尺度上都观察到，随着 SWC 措施实施年数的增加，由于缺乏维护，其有效性下降。该研究还表明，将样地数据外推到流域尺度会导致对净侵蚀的估计过高或过低。在流域层面实施的 SWC 实践使产沙量减少了约 74%（2014 年），尽管由于 SWC 干预导致的沉积物减少幅度随着时间的推移而减少。在这两个尺度上都观察到，随着 SWC 措施实施年数的增加，由于缺乏维护，其有效性下降。该研究还表明，将样地数据外推到流域尺度会导致对净侵蚀的估计过高或过低。在流域层面实施的 SWC 实践使产沙量减少了约 74%（2014 年），尽管由于 SWC 干预导致的沉积物减少幅度随着时间的推移而减少。在这两个尺度上都观察到，随着 SWC 措施实施年数的增加，由于缺乏维护，其有效性下降。该研究还表明，将样地数据外推到流域尺度会导致对净侵蚀的估计过高或过低。