PROGRESS IN GEOGRAPHY ›› 2015, Vol. 34 ›› Issue (8): 1039-1051.doi: 10.18306/dlkxjz.2015.08.011

• Orginal Article • Previous Articles     Next Articles

Scale effect of the impact on runoff of variations in precipitation/vegetation: taking northern Shaanxi loess hilly-gully region as an example

DING Jingyi1(), ZHAO Wenwu1,*(), WANG Jun2, FANG Xuening1   

  1. 1. College of Resources and Technology, State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
    2. Key Laboratory of Land Consolidation and Rehabilitation, Ministry of Land and Resources, Beijing 100035, China
  • Online:2015-08-25 Published:2015-08-25
  • Contact: ZHAO Wenwu;


Water conservation capability of the loess plateau increased significantly since the Grain for Green project started. At the same time, the amount of runoff significantly reduced, resulting in the question of how to balance the water conservation needs and the need for water supply in the region. In order to explore causes of the runoff reduction and provide support for balancing different needs for water at different scales, the variation of precipitation and vegetation as well as the scale effect of its impact on runoff in northern Shaanxi loess hilly-gully region during 2006 to 2011 were examined. The results show that: Precipitation of flood season gradually reduced from southeast to northwest in the study area. During the research period, vegetation restored significantly, nearly 80% of vegetated area was improved, especially in areas with poor vegetation conditions. Precipitation and runoff had significant positive correlation. With the increase of sub-watershed area,the correlation of precipitation and runoff increased, which shows a clear scale effect. The main reason was that land use structure above 15° of slope changed along with the spatial scale—vegetation types at steep slope tended to be homogenous and forest that has significant water conservation function decreased along with the increase in sub-watershed area. The correlation between NDVI and runoff was neither significant nor forming a clear relationship with the area of sub-watersheds, therefore the scale effect of vegetation influence on runoff was not obvious.

Key words: NDVI, precipitation, runoff, scale effect, tradeoff, loess hilly-gully region