Surface and subsurface runoff generation processes and their influencing factors on a hillslope in northern China

Tonggang Fu; Jintong Liu; Hui Gao; Fei Qi; Feng Wang; Mei Zhang

doi:10.1016/j.scitotenv.2023.167372

Surface and subsurface runoff generation processes and their influencing factors on a hillslope in northern China

Sci Total Environ. 2024 Jan 1:906:167372. doi: 10.1016/j.scitotenv.2023.167372. Epub 2023 Sep 25.

Authors

Tonggang Fu¹, Jintong Liu², Hui Gao¹, Fei Qi³, Feng Wang³, Mei Zhang³

Affiliations

¹ Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China.
² Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China. Electronic address: jtliu@sjziam.ac.cn.
³ Key Laboratory of Agricultural Water Resources, Hebei Laboratory of Agricultural Water-Saving, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang 050021, China; University of Chinese Academy of Sciences, Beijing 100049, China.

PMID: 37758127
DOI: 10.1016/j.scitotenv.2023.167372

Abstract

Runoff processes are essential to the hydrological cycle in mountainous areas. However, many aspects of surface and subsurface runoff generation mechanisms and their influencing factors remain to be fully understood. In this study, rainfall simulation experiments were conducted in micro runoff plots in different slope positions on a typical hillslope to explore runoff processes and their influencing factors in the Taihang Mountain region in northern China. The surface and subsurface runoff and soil water content (SWC) variation processes were analyzed. Moreover, the impact of the soil properties, such as soil saturated hydraulic conductivity (K_s), bulk density (BD), capillary porosity (CP), non-capillary porosity (NCP), and soil organic matter (SOM), on these processes were investigated. The results revealed that the response of the SWC to rainfall was significantly different in different soil layers and slope positions. The response time was slower and the period was longer on the lower slope. However, the middle and upper slopes had a faster response time and shorter period. The surface runoff was the dominant type in the lower slope (67.26 % of the total runoff), while the subsurface runoff was the dominant type in the middle (78.83 %) and upper (83.67 %) slopes. The subsurface runoff was mainly generated in the 40 cm layer on the lower slope, 20 and 30 cm layers on the middle slope, and 30 and 40 cm layers on the upper slope. These layers exhibited good correspondence with the K_s' vertical distribution, but were inconsistent with the other soil properties. These results indicate that the K_s was the most critical factor influencing the runoff generation process. The ratio of the upper layer's horizontal K_s to the lower layer's vertical K_s controlled the subsurface runoff generation process in the hillslope. These findings provide useful information for understanding the hydrological processes in mountainous areas.

Keywords: Anisotropy of soil properties; Interflow; Rainfall simulation; Saturated hydraulic conductivity; Taihang Mountain region.