Influences of rock fragments on the hydraulics and erosion of concentrated runoff in steep spoil heaps on the Loess Plateau of China  

作　　者：Wenzhao Guo Hongliang Kang Xiao Yu Wenlong Wang Pei Tian 

机构地区：[1]State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Water and Soil Conservation,Northwest Agriculture&Forestry University,Yangling 712100,China [2]Key Laboratory for Geographical Process Analysis&Simulation of Hubei Province,Central China Normal University,Wuhan 430079,China

出　　处：《International Journal of Sediment Research》2022年第5期553-562,共10页国际泥沙研究（英文版）

基　　金：subsidized by the China Postdoctoral Science Foundation(Grant Number 2020M683591);the Natural Science Basic Research Program of Shaanxi Province(Grant Number 2021JQ-165);the Open Research Program of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(Grant Number A314021402-2005);the National Key Research and Development Program of China(Grant Number 2016YFC0501604)。

摘　　要：The soil-rock mixed spoil heaps are prone to severe soil erosion during heavy rain,causing severe land degradation and ecological and environmental damage.Nevertheless,past research on the erosion on spoil heaps has focused on soil particles that were readily eroded and disregarded the rock fragments(RF)that were not readily eroded.To explore the effect of the RF embedded in spoil heaps on the hydraulics of and erosion caused by concentrated runoff,scour-erosion experiments were implemented on three types of spoil heaps:RF=7%,RF=45%,and RF=69%.The RF clearly reduced runoff and erosion on steep spoil heaps.As the RF increased from 7%to 69%,the runoff intensity and runoff coefficient decreased by 72.9%-79.1%and 83.2%-84.1%respectively,and the sediment concentration,soil denudation rate,and total soil loss decreased by 36.0%-47.8%,83.7%-87.1%,and 87.0%-92.3%,respectively.Narrow rills were generated during the experiments,and the RF distinctly influenced the rill characteristics.High contents of RF restrained rill retreating and undercutting,and promoted rill widening.With an increase in RF,the flow shear stress and stream power gradually decreased,and the Darcy-Weisbach roughness coefficient increased.These findings imply that the RF dissipated the flow energy and reduced soil detachment capacity and sediment transport capacity.Soil detachment is strongly related to the Darcy-Weisbach roughness coefficient,Reynolds number,and runoff intensity,which may be the preferred descriptors of soil detachment.The current findings indicate that embedded rock fragments could effectively reduce soil loss on steep spoil heaps.

关 键 词：Soil erosion RUNOFF Rock fragments(RF) RILLS Chinese loess plateau 

分 类 号：S157.1[农业科学—土壤学]