BackgroundWater induced soil erosion has been continued to threaten the land resources in sub humid northwestern highlands of Ethiopia. Soil and water conservation measures have been implemented without site-specific scientifically quantified soil erosion data and priority bases. In this regard, quantitative analysis of soil erosion and its spatial variation plays a decisive role for better evidence and priority based implementation. Thus, this study aimed to estimate potential soil loss, identify hotspot areas, and prioritize for conservation measures in Gumara watershed using RUSLE, GIS and remote sensing techniques’.ResultThe study result showed that soil loss due to water erosion was found to be a critical problem in the watershed. It ranges from nearly zero in gentle slope of forest lands to 442.92 t ha−1 year−1 on very steep slope cultivated lands. A total of 9.683456 million t of gross surface soil has been lost annually, with an average soil erosion rate of 42.67 t ha−1 year−1. Of which 62.1% was generated from cultivated land. The model result indicated a high spatial variability of soil erosion within the watershed. High intensity of soil erosion has been principally attributed to slope and land use/covers. The study further estimated that about 63.1% of the total soil loss was generated from only 29.3% of the area delineated as very severe soil erosion severity class. Soil erosion rate for 71.7% of the watershed area was beyond the maximum tolerable soil erosion limit estimated for Ethiopian highlands (> 18 t ha−1 year−1). The sub-watershed severity class map revealed that 3814 ha of the sub-watershed area was evaluated as very severe level of soil erosion severity class.ConclusionSoil erosion in the watershed has been a threatening problem for agricultural production to day, its sustainability and to be worsening in the future unless remedial measures were taken, mainly due to human intervention. Therefore, Gumara watershed needs immediate intervention for better conservation planning by considering identified priority classes and hotspot areas.

中文翻译：

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使用 RUSLE 和 GIS 技术对古马拉流域进行更好的保护规划的潜在土壤侵蚀估计和区域优先排序

背景水土流失持续威胁着埃塞俄比亚西北半湿润高地的土地资源。实施了水土保持措施，没有特定地点科学量化的土壤侵蚀数据和优先依据。在这方面，土壤侵蚀及其空间变化的定量分析对于更好的证据和基于优先级的实施起着决定性作用。因此，本研究旨在利用 RUSLE、GIS 和遥感技术来估计古马拉流域的潜在土壤流失，确定热点区域，并优先采取保护措施。结果研究结果表明，水蚀造成的土壤流失是一个关键流域的问题。它的范围从林地缓坡的近零到442。92 t ha−1 year−1 在非常陡峭的坡度耕地上。每年共流失表层土壤总量968.3456万吨，平均土壤侵蚀率为42.67吨公顷-1年-1。其中62.1%来自耕地。模型结果表明流域内土壤侵蚀的空间变异性很大。土壤侵蚀的高强度主要归因于坡度和土地利用/覆盖。该研究进一步估计，大约 63.1% 的土壤流失总量仅来自划定为非常严重的土壤侵蚀严重程度等级的 29.3% 的区域。流域面积 71.7% 的土壤侵蚀率超出了埃塞俄比亚高地估计的最大可容忍土壤侵蚀极限（> 18 t ha−1 year−1）。子流域严重度等级地图显示，子流域面积的 3814 公顷被评估为非常严重的土壤侵蚀严重度等级。结论流域水土流失一直是当今农业生产、其可持续性和有待解决的威胁问题。除非采取补救措施，否则未来会恶化，这主要是由于人为干预。因此，古马拉流域需要立即干预，通过考虑确定的优先级和热点区域来更好地进行保护规划。