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Arid Land Geography ›› 2025, Vol. 48 ›› Issue (3): 380-390.doi: 10.12118/j.issn.1000-6060.2024.179

• Climatology and Hydrology • Previous Articles     Next Articles

Regional differences and threshold of ecological base flow in the Qinling Mountains-Loess Plateau region

YANG Xiaoya1(), YU Kunxia1(), LI Zhanbin1, LI Peng1,2, LIU Yonggang3, MO Shuhong1, YANG Jianhong3   

  1. 1. State Key Laboratory of Eco-Hydraulics in Northwest Arid Region of China, Xi’an University of Technology, Xi’an 710048, Shaanxi, China
    2. China Key Laboratory of National Forestry and Grassland Administration on Ecological Hydrology and Disaster Prevention in Arid Regions, Xi’an University of Technology, Xi’an 710048, Shaanxi, China
    3. Shaanxi Provincial Water Resources and River Reservoir Dispatching Center, Xi’an 710004, Shaanxi, China
  • Received:2024-03-18 Revised:2024-06-04 Online:2025-03-25 Published:2025-03-14
  • Contact: YU Kunxia E-mail:yangxiaoya0212@163.com;yukunxia@126.com

Abstract:

The Qinling Mountains-Loess Plateau geological and geomorphological continuum features a fragile ecosystem where river ecological base flow and its thresholds are critical for ecosystem protection. This study examines the Qinling Mountains-Loess Plateau region in China, constructing a system of 22 ecological base flow influencing factors, including climate, vegetation, topography, soil structure, watershed morphology, and socio-economic variables. Using a self-organizing map (SOM) neural network and K-means clustering analysis, the region was divided into four sub-regions: the central Loess Plateau, southern Qinling, northern Qinling, and northwestern Loess Plateau. Partial least squares structural equation modeling (PLS-SEM) was applied to model and analyze ecological base flow influencing factors in three sub-regions. The results indicate that: (1) Ecological base flow is primarily influenced by precipitation concentration in the central Loess Plateau, by annual mean temperature in the southern Qinling, and by soil moisture content in the northern Qinling. (2) Significant regional differences were observed in ecological base flow thresholds, with values of 7.9% for the central Loess Plateau, 9.5% for the southern Qinling, 7.5% for the northern Qinling, and 4.1% for the northwestern Loess Plateau. (3) A linear regression model was developed to calculate and simulate ecological base flow, with determination coefficients exceeding 0.87, accounting for regional differences in environmental response. These findings provide a robust scientific basis for the quantitative estimation of ecological base flow, offer insights into river health maintenance and sustainable water resource utilization, and hold substantial theoretical and practical significance.

Key words: ecological base flow, cluster analysis, flow threshold, structural equation, influencing factors