JOURNAL OF NATURAL RESOURCES ›› 2019, Vol. 34 ›› Issue (3): 563-572.doi: 10.31497/zrzyxb.20190310

• Resources Economics • Previous Articles     Next Articles

Baseflow variation and driving factors for the last six decades in a watershed on the Loess Plateau, Northern China

KANG Xiao-yu1,2,3,4(), ZHANG Zhi-qiang1,2,3,4(), CHEN Li-xin1,2,3,4, LENG Man-man1,2,3,4, YANG Feng-wei5   

  1. 1. College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2. Key Laboratory of Soil and Water Conservation, State Forestry Administration, Beijing Forestry University, Beijing 100083, China
    3. National Field Research Station of Forest Ecosystem, Jixian 042200, Shanxi, China
    4. Beijing Water and Soil Conservation Engineering Technology Research Center, Beijing 100083, China
    5. National Forestry Administration Eucalyptus Research and Development Center, Zhanjiang 524022, Guangdong, China
  • Received:2018-09-02 Revised:2018-12-17 Online:2019-03-28 Published:2019-03-28

Abstract:

As an important part of streamflow and water cycle in a watershed, base flow can not only provide reliable water supply but also maintain healthy watershed ecologically and environmentally. It is of great significance to divide the base flow accurately from the measured streamflow and to analyze its variations for understanding the dynamics of base flow changes and managing water resources. We used the measured daily streamflow data from Daning Hydrological Station of Xinshui River Basin (3992 km2) located on the Loess Plateau of northern China, climate data measured by meteorological stations and raingauge stations located within and in the vicinity of the basin from 1955 to 2015 and the GIMMS-NDVI data to explore the dynamic changes of base flow. Base flow partitioning was conducted by using digital filtering method (3 times, α=0.925) from the daily streamflow data. Mann-Kendall test, Pettitt test, wavelet analysis and Hurst test were performed to explore the base flow changes in the aspects of trend, turning point, periodic behavior, and sustainability at annual scales. Averaged annual base flow from the basin was 45 million m3 and the base flow index (BFI) was 0.368 between 1955 and 2015. There were significant decreasing trends for yearly base flow (P<0.01), with the turning points occurring in the year of 1985. In addition, a 27-year periodical cycle was observed for annual base flow. It was predicted that the annual base flow will be further reduced in the future as indicated by a positive correlation between historical change and the future regime (H>0.50). Double mass analysis indicated that climate variability and human activities have contributed to a significant decrease in base flow. Precipitation was the major climate factor rather than temperature, which caused the decrease of base flow. The base flow is divided into three stages by the double mass curve method. Human activities affected the base flow by changing vegetation coverage, exploiting groundwater, mining coals and taking measures in soil and water conservation. Compared with the first stage, the proportion of precipitation and human activities in the second and third stages was 25.89%, 74.11% and 0.37%, 99.63%, respectively. There has been an increased impact of human activities on the decreased base flow since the beginning of the 21st century.

Key words: Loess Plateau, middle-scale watershed, base flow variation, driving factors, Loess Plateau, middle-scale watershed, base flow variation, driving factors