Vol15 No.8: 1825-1835
【Title】Identifying the driving factors of sediment delivery ratio on individual flood events in a long-term monitoring headwater basin
【Author】WANG Ling-ling1,2; YAO Wen-yi1; TANG Jia-liang3*; WANG Wen-long2; HOU Xin-xin1
【Addresses】1 Yellow River Institute of Hydraulic Research, Key Laboratory of the Loess Plateau Soil Erosion and Water Loss Process and Control of Ministry of Water Resources, Zhengzhou 450003, China; 2 College of Resource and Environment, Northwest A & F University, Shaanxi 712100, China; 3 Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China
【Corresponding author】TANG Jia-liang
【Citation】Wang LL, Yao WY, Tang JL, et al. (2018) Identifying the driving factors of sediment delivery ratio on individual flood events in a long-term monitoring headwater basin. Journal of Mountain Science 15(8). https://doi.org/10.1007/s11629-017-4739-7
【Abstract】The Sediment Delivery Ratio (SDR) has multi-fold environmental implications both in evaluating the soil and water losses and the effectiveness of conservation measures in watersheds. Various factors, including hydrological regime and watershed properties, may influence the SDR at inter-annual timescales. However, the effect of certain important dynamic factors, such as rainfall peak distribution, runoff erosion power and sediment bulk density, on the sediment delivery ratio of single flood events (SDRe) has received little attention. The Qiaogou headwater basin is in the hilly-gully region of the Chinese Loess Plateau, and it encompasses a 0.45 km2 catchment. Three large-scale field runoff plots at different geomorphological positions were chosen to obtain the observation data, and the 20-year period between 1986 and 2005 is presented. The results showed that the SDRe of the Qiaogou headwaters varied from 0.49 to 2.77. Amongthe numerous influential factors, rainfall and runoff were the driving factors causing slope erosion and sediment transport. The rainfall erosivity had a significant positive relationship with the sediment transport modulus (R2=0.85, P<0.01) but had no significant relationship with SDRe. The rainfall peak coefficient was significantly positively correlated with the SDRe (R2=0.64, P<0.05), indicating the influence of rainfall energy distribution on the SDRe. The runoff erosion power index was not only significantly related to the sediment transport modulus (R2=0.84, P<0.01) but also significantly related to theSDRe (R2=0.57, P<0.01). In addition, the relative bulk density was significantly related to the SDRe, indicating that hyper-concentrated flow characteristics contributed to more transported sediment in the catchment. Thus, the rainfall peak coefficient, runoff erosion power and sediment relative bulk density could be used as dynamic indexes to predict the SDRe in the hilly areas of the Chinese Loess Plateau.
【Keywords】Sediment delivery ratio; Single flood events; Rainfall erosivity; Runoff erosion power; Hyper-concentrated flow