Analysis of Runoff and Sediment Losses from a Sloped Roadbed under Variable Rainfall Intensities and Vegetation Conditions

Chunfeng Jia,Xinxiao Yu,Baoping Sun,Xiaohui Yang

doi:10.3390/su12052077

Abstract

Vegetation plays an important role in reducing soil erosion. By exploring the allocation and coverage of different types of vegetation, we can improve management practices that can significantly reduce soil erosion. In this experiment, we study runoff and sediment losses on a shrub-grass planted, grass planted, and bare slope under different rainfall intensities. Results showed that the runoff generation time for the three subgrade types decreased as rainfall intensity increased (p < 0.05). The slopes planted with either grass or shrub-grass were able to effectively delay runoff generation. As rainfall intensity increased, the runoff amount increased for all treatments, with runoff in the bare slope increasing the most. The runoff reduction rate from the shrub-grass slope ranged from 54.20% to 63.68%, while the reduction rate from the slope only planted with grass ranged from 38.59% to 55.37%. The sediment yield from the bare slope increased from 662.66 g/m2 (15 mm/h) to 2002.95 g/m2 (82 mm/h) with increasing rainfall intensity in the plot. When compared with the bare slope, both the shrub-grass and planted grass slopes were able to retain an additional 0.9 g/m2 to 4.9 g/m2 of sediment, respectively. An accurate relationship between rainfall intensity, sloped vegetation types, and runoff reduction rate was obtained by regression analysis and validated. These results can provide a reference for improving soil and water conservation via improved vegetation allocation on a sloped roadbed.

Highlights

IntroductionWhen public transportation systems such as roads and railways are improved, the construction of slopes via excavation and fill can change the original landform, increasing discharge and erosion from sloped surfaces, with consequences for both natural and human systems
The process of modernization, construction, and land use change can have a negative impact on the environment unless the processes by which changes are made are well-understood and sustainable [1].When public transportation systems such as roads and railways are improved, the construction of slopes via excavation and fill can change the original landform, increasing discharge and erosion from sloped surfaces, with consequences for both natural and human systems
The sediment yield from the bare slope increased from 662.66 g/m2 (15 mm/h) to 2002.95 g/m2 (82 mm/h) with increasing rainfall intensity in the plot

Summary

Introduction

When public transportation systems such as roads and railways are improved, the construction of slopes via excavation and fill can change the original landform, increasing discharge and erosion from sloped surfaces, with consequences for both natural and human systems. Adding vegetation to slopes is beneficial by reducing sediment loads associated with runoff, and has the added effect of regulating water resources and conserving groundwater [7]. These practices can help with ecological restoration and have gradually become an important method of protecting railway subgrade slopes [1].

Objectives

Results

Conclusion