Identifying the driving factors of sediment delivery ratio on individual flood events in a long-term monitoring headwater basin  

作　　者：WANG Ling-ling YAO Wen-yi TANG Jia-liang WANG Wen-long HOU Xin-xin 

机构地区：[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 [2]College of Resource and Environment, Northwest A & F University [3]Institute of Mountain Hazards and Environment, Chinese Academy of Sciences

出　　处：《Journal of Mountain Science》2018年第8期1825-1835,共11页山地科学学报（英文）

基　　金：jointly supported by the National key research priorities program of China (2016YFC0402402);National Major Science and Technology Program for Water Pollution Control and Treatment (2017ZX07101001);the National Natural Science Foundation (41301299);the Construction Project of Innovative Scientific and Technological Talents in Henan Province (162101510004)

摘　　要：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 interannual 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 km^2 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. Among the 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(R^2=0.85, P<0.01) but had no significant relationship with SDRe. The rainfall peak coefficient was significantly positively correlated with the SDRe(R^2=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(R^2=0.84, P<0.01) but also significantly related to the SDRe(R^2=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.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 interannual 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 km^2 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. Among the 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（R^2=0.85, P〈0.01） but had no significant relationship with SDRe. The rainfall peak coefficient was significantly positively correlated with the SDRe（R^2=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（R^2=0.84, P〈0.01） but also significantly related to the SDRe（R^2=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.

关 键 词：Sediment delivery ratio Single flood events Rainfall erosivity Runoff erosion power Hyper-concentrated flow 

分 类 号：S0[农业科学]