Developmetn stage threshold of watershed Landforms in Loess Plateau and separation of erosion mechanism |
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| Authors: | LU Zhong-chen CHEN Shao-feng YUAN Bao-yin CHEN Hao |
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| Institution: | 1. Eco-Environment Research Center,CAS,Beijing 100085,China;
2. Institute of Policy and Management Science,CAS,Beijing 100080,China;
3. Institute of Geology,CAS,Beijing 1000029,China;
4. Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China |
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| Abstract: | Threshold is a limit and marginal point when a qualitative change takes place.Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s,the quantitative research on watershed landform development stage has come true.Davis proposed a three-stage model on landform evolution:young ,mature and old stages.Thereafter Stahler quantified this model by hypsometric analysis method.The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage,because of the uncertainty on stage delimitaion.To meet this shortcoming,this paper presents an integral erosion value method.A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method.The result shows that gullied loessial hilly area is at the mature stage,and gullied loessial tableland area is at the young stage.It is estimated that from the point of erosion related sediment yield,natural erosion accounts for 70% of the total erosion amount,and artificial accelerating erosion is 30%.Therefore soil and water conservation is very crucial for the Loess Plateau. |
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| Keywords: | landform development stage hypsometric analysis method integral erosion value natural erosion artificial accelerating erosion |
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