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| Sediment sources analysis of the Yangou watershed under a certain rainstorm event in the Hilly-gully Region of Loess Plateau |
| Xu Xuexuan,Ju Tongjun,Zheng Shiqing |
| Institute of Soil and Water Conservation,Northest A&F University;Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources: 712100,Yangling, Shaanxi,China |
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Abstract The Yangou watershed is located in Yanan in the most erosive region.At present the vegetation restoration in large scale and high intensity of oil exploiting had brought huge influence on driving forces for the erosion environment change.The balance of slope land erosion and road erosion had been changed a lot.After most slope land had been restored by vegetation,road erosion became more and more important,especially under the massive road constructing for oil industry.In this paper,sediment yield under the event of rainfall on July 2,2005 which was a rainstorm with yearly possibility of 20% had been surveyed and analyzed, that including sediment from land under different uses(crop-land plot,vegetation plots,hard road surface) and also 3 types roads(narrow mountain-road,mountain-road,and mountain-transport way).The sediment yield intensity of the 3 type roads was respectively as 500 t/km<sup>2</sup>,3 163 t/km<sup>2</sup>,and 13 500 t/km<sup>2</sup> under the rainfall event.On the other hand,the sediment from cropland and grass,shrub land was within 6-184 t/km<sup>2</sup>.The results also showed that sediment from road area which only had 1% of total area accounted for 42.3% of the total sediment yield,far beyond that from other land types in the watershed.Sediment from grass-land and shrub-land,which had 70.5% of watershed area,shared 26.7% of the total sediment.The research also showed that the 41.2% of total sediment could be detained by re-vegetation.On the contrary,that road constructing brought heavy sediment which off-benefit by 58.4%.Based on this research,some key suggestions had been put forward that could be used to adjust the strategy form slope management to road erosion protection.
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Received: 22 June 2007
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