| 长江源区不同植被覆盖下产流产沙效应初步研究 |
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| 引用本文： | 李元寿,王根绪,沈永平,王军德,王一博.长江源区不同植被覆盖下产流产沙效应初步研究[J].冰川冻土,2005,27(6):869-875. |
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| 作者姓名： | 李元寿 王根绪 沈永平 王军德 王一博 |
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| 作者单位： | 1. 中国科学院, 寒区旱区环境与工程研究所, 寒旱区流域水文及应用生态实验室, 甘肃, 兰州, 730000;2. 中国科学院, 水利部, 成都山地灾害与环境研究所, 四川, 成都, 610041;3. 兰州大学资源与环境学院, 甘肃, 兰州, 730000 |
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| 基金项目： | 中国科学院资助项目
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中国科学院"百人计划" |
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| 摘 要： | 在长江源区北麓河支流左冒西孔曲流域建立了不同植被覆盖下的天然径流观测场,观测天然降水和人工模拟降水在相同坡度不同植被覆盖下降水的产流产沙效应.结果表明:在典型高寒草甸草地30°坡面上,相同降水条件下,30%覆盖度的场地的地表径流产出量明显大于覆盖度92%和68%两个场地,同时产沙量也显著高于两个高盖度场地的,平均单次降水形成的泥沙量是后两种情形的2~4倍,由此造成地表侵蚀量平均为后两种情形的3~10倍;但在相同降水条件下,92%高盖度场地产生的径流量比68%盖度场地产生的径流量大,产沙量刚好相反.不同降水形态对于下垫面产流产沙过程也具有明显影响,无论下垫面状况如何,在几种降水形态中,降雪融水的产流量最大,产沙量最小.人工模拟的结果表明,对于覆盖度<68%的中、强度退化草地,次降水量在3.5 mm时,就形成了较为明显的径流和产沙效应.当次降雨量达到7.2 mm,降雨持续时间30 min,覆盖度为30%、68%和92%的25 m2场地分别形成2885 mL、2450 mL和1030 mL的径流量;覆盖度<30%的退化草地泥沙含量明显高于高覆盖度的,相同降水形成的平均泥沙含明显高于高覆盖度的, 相同降水形成的平均泥沙含量高达2~7倍.
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| 关 键 词： | 长江源区 植被覆盖 产流 产沙 |
| 文章编号： | 1000-0240(2005)06-0869-07 |
| 收稿时间： | 2005-09-23 |
| 修稿时间： | 2005年9月23日 |
Impacts of Land Coverage on Runoff Production and Sediment Yield in the Headwaters of the Yangtze River, China |
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| LI Yuan-shou,WANG Gen-xu,SHEN Yong-ping,WANG Jun-de,WANG Yi-bo.Impacts of Land Coverage on Runoff Production and Sediment Yield in the Headwaters of the Yangtze River, China[J].Journal of Glaciology and Geocryology,2005,27(6):869-875. |
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| Authors: | LI Yuan-shou WANG Gen-xu SHEN Yong-ping WANG Jun-de WANG Yi-bo |
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| Institution: | 1. Laboratory of Watershed Hydrology and Ecology, CAREERI, CAS, Lanzhou Gansu 730000, China;2. Institute of MountainHazard and Environment, Chinese Academy of Sciences & Ministry of Water Conservancy, Chengdu Sichuan 610041, China;3. College of Resources and Environment, Lanzhou University, Lanzhou Gansu 730000, China |
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| Abstract: | The small Zuomaoxikongqu River in the headwaters of the Yangtze River,where vegetation is simple and dominated by cold alpine meadows and alpine steppe meadows,are selected as typical catchments to study contrastively the impacts of alpine land coverage change on rainfall-runoff processes and soil erosion.The study indicates that in the field of alpine meadow with 30? slope,the runoff production in the meadow of 30% land-coverage is apparently more than that in the meadows of 92% and 68% land-coverage under the same condition of precipitation.So is sediment yield.The average sediment amount for a precipitation event in the meadow of 30% land-coverage is twice to four times that in the meadows of 92% and 68% land-coverage.Therefore,the erosion amount in the surface in the former is 3~10 times that of the latter two.Under the same precipitation,the runoff production in the meadows of 92% land-coverage is higher than that in the meadows of 68% land-coverage,and the sediment yield is just opposite.The precipitation form has a pronounced effect on the sediment yield.Solid precipitation results in more runoff production and less sediment yield.The study supports the concept of vegetation being a major control factor for runoff production and sediment yield.The simulative results of this study indicate that,for a middle-grade degraded alpine meadow land with coverage less than 68%,it will be apparent runoff production and sediment yield,when the a precipitation event reaches 3.5 mm.Runoff of 2885 mL,2450 mL and 1030 mL have been measured in the field of 25 m2,when precipitation reaches 7.2 mm and lasts 30 minutes.The sediment content in the serious degraded alpine meadow with coverage below 30% is apparently higher,on average,twice to seven times that with high coverage. |
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| Keywords: | alpine meadowland land coverage runoff sediment yield headwaters of the Yangtze River |
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