TITLE:
An Optical High and Medium Spatial Resolution Approach for Erosion-Prone Areas Assessment in Mustang, Nepal
AUTHORS:
Kabir Uddin, Madhav Dhakal, Govinda Joshi
KEYWORDS:
Remote Sensing, GIS, OBIA, Soil Erosion, Watershed
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.4,
April
24,
2014
ABSTRACT:
Every
year during the rainy season, water-induced soil erosion poses serious
spatial-environmental problems, causing heavy damage to agricultural lands,
sedimentation in reservoirs, and water quality problems in nearby surface water
bodies, from the plains to the mountain areas in Nepal. The goal of this study
is to identify potential areas for soil erosion in sub and macro watershed in
Mustang, Nepal using remote sensing (RS) and geographic information systems
(GIS) techniques. The study examines the possibility of advanced mapping of soil
erosion-prone areas using a high spatial resolution image of QuickBird
satellite and medium spatial resolution of Landsat satellite. The satellite
image was classified using object-based image analysis (OBIA) techniques,
taking into account spectral, spatial, and context information as well as
hierarchical properties. The resulting land cover classification was thereafter
combined with additional data in ArcGIS, where the input layers were
reclassified and all classes of the input layers were ranked according to their
proneness to soil erosion. Soil erosion-prone areas were delineated in five classes
ranging from “very high” to “very low”. Using high spatial resolution image the
study revealed that 22% area categorized as “high erosion-prone” areas and 5%
as “very high” or “extremely erosion-prone”. Using medium resolution image the
study exposed that 27% area categorized as “high erosion-prone” areas and 6% as
“very high” or “extremely erosion-prone”. Comparison between two analysed
erosion results almost all the erosion zone area was very close excluding
medium erosion-prone category. The study proved GIS modeling techniques can
successfully identify soil erosion-prone areas. The soil erosion-prone map
produced out of the exercise can be used in decision making, particularly in
selecting conservation measures to reduce soil loss.