Research Paper
Assessment of soil erosion in a tropical mountain river basin of the southern Western Ghats,India using RUSLE and GIS
Jobin Thomas a ,b ,*,Sabu Joseph b ,K.P.Thrivikramji c
a
EWRE,Department of Civil Engineering,Indian Institute of Technology Madras,Chennai,600036,Tamil Nadu,India b
depositionDepartment of Environmental Sciences,University of Kerala,Thiruvananthapuram,695581,Kerala,India c
Center for Environment and Development,Thiruvananthapuram,695013,Kerala,India
a r t i c l e i n f o
Article history:
Received 27October 2016Received in revised form 7May 2017
Accepted 21May 2017
Available online 27June 2017Handling Editor:Sohini Ganguly Keywords:Soil erosion RUSLE
Transport limited sediment delivery Muthirapuzha river basin Western Ghats Kerala
a b s t r a c t
Revised Universal Soil Loss Equation (RUSLE)model coupled with transport limited sediment delivery (TLSD)function was used to predict the longtime average annual soil loss,and to identify the critical erosion-/deposition-prone areas in a tropical mountain river basin,viz.,Muthirapuzha River Basin (MRB;area ¼271.75km 2),in the southern Western Ghats,India.Mean gross soil erosion in MRB is 14.36t ha À1yr À1,whereas mean net soil erosion (i.e.,gross erosion e deposition)is only 3.60t ha À1yr À,roughly 25%of the gross erosion).Majority of the basin area (w 86%)experiences only slight erosion (<5t ha À1yr À1),and nearly 3%of the area functions as depositional environment for the eroded sedi-ments (e.g.,the terraces of stream reaches,the gentle plains as well as the foot slopes of the plateau scarps and the terrain with concordant summits).Altho
ugh mean gross soil erosion rates in the natural vegetation belts are relatively higher,compared to agriculture,settlement/built-up areas and tea plan-tation,the sediment transport ef ficiency in agricultural areas and tea plantation is signi ficantly high,re flecting the role of human activities on accelerated soil erosion.In MRB,on a mean basis,0.42t of soil organic carbon (SOC)content is being eroded per hectare annually,and SOC loss from the 4th order sub-basins shows considerable differences,mainly due to the spatial variability in the gross soil erosion rates among the sub-basins.The quantitative results,on soil erosion and deposition,modelled using RUSLE and TLSD,are expected to be bene ficial while formulating comprehensive land management strategies for reducing the extent of soil degradation in tropical mountain river basins.
Ó2018,China University of Geosciences (Beijing)and Peking University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (/
licenses/by-nc-nd/4.0/).
1.Introduction
Soil erosion is a natural process,where the extent and magni-tude of soil loss are controlled by vario
us environmental de-terminants,such as climate,soil,topography and vegetation (Wischmeier and Smith,1978;Renard et al.,1997;Mutua et al.,2006;Butt et al.,2010).However,human interferences,via land use modi fication,deforestation,agricultural practices and con-struction activities can accelerate the rate of soil erosion.Globally,total land area affected by water erosion is 1094Mha,of which 751Mha is seriously deteriorated (Lal,2003),and the annual sediment transport into the ocean by the world ’s rivers was
estimated to be 15e 30billion tones (Milliman and Syvitski,1992;Walling and Webb,1996).In the Indian context,approximately 91%of the total geographic area falls under five erosion categories with potential soil erosion rates varying from <5to 40t ha À1yr À1,and requires various kinds of soil conservation practices (Sharda et al.,2013).Although geologic erosion -a slow and steady pro-cess -is essential for soil formation,accelerated soil erosion should be reduced to ward off the adverse effects on soil fertility,agri-cultural productivity,water quality and reservoir capacity (Lal,1998,2001;Blanco-Canqui and Lal,2008).Soil erosion and depo-sition have signi ficant importance in balancing the atmospheric carbon budget,and hence,the potential impacts of soil erosion/deposition need to be considered in the global carbon dynamics also (Lal,2003;Liu et al.,2003;Berhe et al.,2007;Doetterl et al.,2012;Imamoglu and Dengiz,2017).
Wide range of soil erosion and sediment transport models,which differ in terms of complexity,processes considered and data
*Corresponding author.EWRE,Department of Civil Engineering,Indian Institute of Technology Madras,Chennai,600036,Tamil Nadu,India.E-mail address:jobinenv@gmail (J.Thomas).
Peer-review under responsibility of China University of Geosciences (Beijing).
H O S T E D  BY
Contents lists available at ScienceDirect China University of Geosciences (Beijing)
Geoscience Frontiers
journal homep age:www.elsevie
r/locate/gsf
/10.1016/j.gsf.2017.05.011
1674-9871/Ó2018,China University of Geosciences (Beijing)and Peking University.Production and hosting by Elsevier B.V.This is an open access article under the CC BY-NC-ND license (/licenses/by-nc-nd/4.0/).
Geoscience Frontiers 9(2018)893e 906

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。