【摘要】 上方来水来沙作为上下不同地貌部位之间水流能量传递的媒介和泥沙输移的载体,对下游侵蚀产沙过程具有重要影响,是土壤侵蚀研究的关键环节。以往研究多侧重于小流域泥沙来源以及上方来水来沙的异位沉积效应,对上方来水来沙的异位侵蚀效应研究相对较少。本文回顾了上方来水来沙异位侵蚀效应的研究方法,在总结归纳前人研究成果的基础上,首次提出了"异位侵蚀"的概念,从异位径流特征、侵蚀产沙等方面,分析了裸露坡面上方来水来沙的异位侵蚀效应,并对水土保持措施异位减蚀作用的研究进展进行了综述。在此基础上,进一步探讨了异位侵蚀研究中的热点和难点问题,提出可从明确异位侵蚀效应概念、探索异位侵蚀影响因素及其机理、阐明上方来水来沙异位侵蚀过程中水沙和能量传递特征、量化水土保持措施异位减蚀作用等4个方面进一步深入研究上方来水来沙的异位侵蚀效应。更多还原

【Abstract】 [Background] Up-slope runoff and sediment play an important role in energy deliver and sediment transport between the adjacent section. The change of up-slope runoff and sediment will affect the soil erosion process of down-slope. Thus,it is the vital content of soil erosion to study the up-slope runoff and sediment. However, previous studies mainly focused on the sediment sources of small watershed and the off-site depositional effects of up-slope runoff and sediment,while less studies focused on the off-site erosional effect of up-slope runoff and sediment. [Methods] This paper reviewed the study methods of the off-site erosional effect of up-slope runoff and sediment. Based on the previous research,the "off-site erosion"was firstly proposed in this paper. And then,it summarized the research achievements of predecessors. In terms of the characteristics of off-site runoff and sediment yield,the paper summarized the off-site erosional effect of up-slope runoff and sediment on the bare slope,and the research progress of the influence of soil and water conservation on the off-site erosional effect.Furthermore,it discussed the hotspots,challenges,and the future research directions of the off-site erosional effect. [Results]"Off-site erosion"refers to the change of downslope runoff characteristics and the sediment yield caused by up-slope runoff and sediment. The up-slope runoff and sediment joined into the down-slope and increased the runoff energy of down-slope. Besides,the runoff velocity,hydraulic radius,Reynolds number and Froude number increased,while resistance coefficient decreased. Based on the analysis of observed data and simulation experiments,the up-slope runoff and sediment would increase the sediment yield of down-slope. However,when the sediment concentration of runoff came to the sediment carrying capacity of runoff,the runoff with sediment couldn’t erosive the down-slope soil,and even to deposit. The soil and water conservation measures on slope decreased runoff amount and sediment yield entering the down-slope. Some scholars thought soil and water conservation on slope decreased the off-site sediment yield,while others drew the opposite conclusion. Engineering measures,such as dams,drastically cut the runoff erosional energy,thus they had the decreased effect on off-site.[Conclusions]"Off-site erosion"is a relatively spatial concept,but how to reasonably define the upslope and down-slope regions,there is still no clear definition. Up-slope runoff and sediment,erosion pattern evolution process and erosion process interacted with each other. Meantime,off-site erosional effect of up-slope runoff and sediment would be impacted by the dynamic change,such as rainfall intensity,underlying surface,sediment concentration and sediment carrying capacity. Further research of the off-site erosional effect of up-slope runoff and sediment could be conducted in confirming the concept of "off-site erosion",exploring the influence factors and mechanism of off-site erosion,illuminating the transfer characteristics of sediment and runoff energy during the off-site erosional process of up-slope runoff and sediment, as well as quantitating the off-site less erosional effect of soil and water conservation.更多还原