Effects of land uses and rainfall regimes on surface runoff andsediment yield in a nested watershed of the Loess Plateau, China
- 1School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- 2Jixian National Forest Ecosystem Observation and Research Station, CNERN, Beijing Forestry University, Beijing, China
Land-use and rainfall characteristics are two crucial influencing factors that affect the surface runoff and soil loss process; however, less attention has been paid to nested watersheds in vulnerable geo-ecosystems. In this study, we analyzed rainfall characteristics impacts on runoff and sediment in one of the nested watersheds, which contains six sub-watersheds with different land uses (secondary forest watershed, mixed forest watershed, closed watershed, plantation watershed, farmland watershed and farming-pastoral watershed) on the Loess Plateau, China. According to rainfall amount, rainfall duration and maximum rainfall intensity within 30 min (I30), 180 rainfall events during 2004–2019 were categorized into four types using K-means clustering method, and different hydrological years were distinguished. The runoff coefficient and sediment yield under the rainfall regime I (little precipitation, moderate duration of precipitation, low intensity of precipitation) were the lowest; under the rainfall regime IV (high precipitation, short duration of precipitation, high intensity of precipitation), these values were the largest. The average runoff coefficient among the six sub-watersheds analyzed varied as follows: farmland watershed (2.42%) > farming-pastoral watershed (2.38%) > closed watershed (1.11%) > secondary forest watershed (1.08%) > mixed forest watershed (0.73%) > plantation watershed (0.43%). The closed watershed had the lowest average sediment yield, while the farming-pastoral watershed showed the highest one. In addition, the runoff coefficient and sediment yield also changed differently in various hydrological years. The results of this study suggest that natural restoration measures are the optimal choice for coordinating the relationship between surface runoff and sediment yield. In future research, enhanced long-term monitoring is needed to accurately describe watershed processes.
How to cite: Zhao, J., Zhang, J., and Yu, Y.: Effects of land uses and rainfall regimes on surface runoff andsediment yield in a nested watershed of the Loess Plateau, China , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4627, https://doi.org/10.5194/egusphere-egu23-4627, 2023.
