延河流域极端暴雨下侵蚀产沙特征野外观测分析

发布时间：2018-11-22 15:57

【摘要】：针对黄土高原目前侵蚀环境明显改善条件下能否经受得住极端暴雨事件的考验及可能出现的问题,该文依据在延河6个典型小流域的植被调查及土壤侵蚀监测结果,分析了2013年极端暴雨条件下延河流域不同尺度的侵蚀产沙特征。结果表明,天然乔木(辽东栎和三角槭)植被的平均侵蚀强度1 000 t/km~2,自然灌木植被在1 118.1~1 161.2 t/km~2之间,演替中后期的草本植被在1 245.2~1 827.8 t/km~2之间,而演替中前期的草本植被在3 087.6~4 408.4 t/km~2之间;人工灌木林(2 119.7~2 183.9 t/km~2)比人工乔木林(2 625.7~5 149.6 t/km~2)具有较强的减蚀能力。坡面良好的植被覆盖能有效抵御暴雨侵蚀,小流域坡面平均侵蚀强度基本2 500 t/km~2;但滑坡侵蚀占主导地位,占各小流域侵蚀总量的49.0%~88.5%,特别是距暴雨中心较近流域的南部2个小流域的滑坡侵蚀可达7 290.3和7 424.9 t/km~2左右。不同小流域内有6.4%~18.3%的侵蚀量淤积在沟道里;延河甘谷驿以上不同河段的淤积量为13.2~145.2万t,平均占总侵蚀产沙量的15%。延河甘谷驿控制区的侵蚀产沙强度变化在2 326.7~7 774.4 t/km~2之间,其中强度为5 000~8 000 t/km~2的面积占59.3%。因此,加强沟间地径流蓄排措施,减轻坡面径流下沟对沟坡重力侵蚀的影响,是土壤侵蚀研究与防治中值得重视的问题。
[Abstract]:In view of whether the loess plateau can withstand the test of extreme rainstorm events and the possible problems under the condition of obvious improvement of erosion environment at present, this paper bases on the results of vegetation investigation and soil erosion monitoring in six typical small watersheds of Yanhe River. The characteristics of erosion and sediment yield in Yanhe River Basin under extreme rainstorm in 2013 are analyzed. The results showed that the average erosion intensity of natural Arbor (Quercus liaotungensis and Acer triangularis) was 1 000 t / km ~ (-2), that of natural shrubs was 1 118.1 ~ 1 161.2 t/km~2, and that of herbaceous vegetation in middle and late stage of succession was 1 245.2 ~ 1 827.8 t/km~2. The herbaceous vegetation in the middle and early stage of succession ranged from 3 087.6 to 4 408.4 t/km~2; Artificial shrub forest (2 119.7N 2 183.9 t/km~2) had stronger ability to reduce erosion than artificial tree forest (2 625.7 (5 149.6 t/km~2). The good vegetation cover on the slope can effectively resist rainstorm erosion, and the average erosion intensity of the small watershed slope is about 2 500 t / km ~ (-1); However, landslide erosion is dominant, accounting for 49.088. 5% of the total erosion in each small watershed, especially in the southern two small watersheds, which are close to the rainstorm center, and can reach about 7 290.3 and 7 424.9 t/km~2. In different small watersheds, 6.4% of the erosion amount is deposited in the channel, and the siltation amount in different reaches above Ganguyi of Yanhe River is 13.2 ~ 1.452 million tons, accounting for 15% of the total erosion sediment yield on average. The intensity of erosion and sediment yield varies from 2 326.7 to 7 774.4 t/km~2 in Ganguyi control area of Yanhe River, of which the area with an intensity of 5 000 ~ 8 000 t/km~2 accounts for 59. 3%. Therefore, it is worthy of attention in the study and control of soil erosion to strengthen the measures of runoff storage and drainage between gullies and to reduce the influence of gully runoff on gravity erosion of gully slope.
【作者单位】：西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;贵州大学生命科学学院;
【基金】：国家重点研发计划项目课题“黄土高原生态修复的土壤侵蚀效应与控制机制(2016YFC0501604)” 国家自然科学基金面上项目“黄丘区坡面退耕与淤地坝对坡沟系统侵蚀产沙的阻控机理(41371280)
【分类号】：S157.1

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