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通过建立三峡库区小流域模型,实施降雨强度分别为60,90,120mm/h的3场人工模拟降雨,并结合REE示踪技术,对小流域模型侵蚀产沙过程进行定量研究。结果表明:3场降雨中,小流域不同地貌部位侵蚀量随着降雨的持续均呈现不同规律的波动性变化。而在土壤侵蚀量的贡献率方面,除Ⅵ区呈现先急剧减小后趋于稳定及V区呈现增加后减小的趋势外,其他各区均呈现稳定增长并趋于稳定。总体来看,沟道系统的侵蚀贡献率均大于坡面系统,并呈现沟道系统贡献率逐渐减小,坡面系统贡献率逐渐增加的趋势。3场降雨试验的实测土壤侵蚀量与示踪计算土壤侵蚀量对比,证明示踪结果具有一定准确性。
Through the establishment of a small watershed model in the Three Gorges Reservoir Area, three artificial simulated rainfalls with rainfall intensities of 60, 90 and 120 mm / h respectively were implemented, and the REE tracing technique was used to quantitatively study the process of soil erosion and sediment yield in small watershed. The results show that the erosion amount of different landforms in the three watersheds fluctuates with different regularities with the continuous rainfall. In terms of the contribution rate of soil erosion, the other districts showed stable growth and stable except for the trend of Ⅵ followed by a sharp decrease first and then a steady trend and the V-zone increasing and then decreasing. Generally speaking, the contribution rate of channel system erosion is greater than that of slope system, and the contribution rate of channel system gradually decreases and the contribution rate of slope system gradually increases. The measured soil erosion amount of three rainfall tests is compared with the soil erosion amount calculated by tracing, which proves that the tracing result has a certain accuracy.