Abstract:
Soil erosion due to water is becoming a serious land degradation problem
in rain fed areas of Pothwar region. Rawal lake, a major source of water supply for
Islamabad and Rawalpindi is undergoing heavy sedimentation due to soil erosion
and its storage capacity has reduced over the past few decades. This research aims
to assess soil erosion risk in Rawal watershed using COordination of Information
on the Environment (CORINE). The factors considered in this model are soil,
precipitation, temperature, slope and vegetation cover. The soil maps were used to
extract soil texture, soil depth and stoniness data which were overlaid to generate
soil erodibility map. The precipitation and temperature data of 18 years (1988-
2005) was used to compute Modified Fournier Index (MFI) and Bagnouls-Gaussen
aridity Index (BGI) that was overlaid to generate erosivity map. Slope was
generated from DEM of 20m spatial resolution which was extracted from
topographic sheet of scale 1 :25,000. Soil erodibility, erosivity and slope maps were
overlaid to produce potential soil erosion risk. NDVI was also calculated using
SPOT-5 satellite image to generate vegetation cover. Finally, actual erosion risk
map was prepared by overlay analysis of potential erosion risk map and vegetation
cover. The results indicated that 25, 48 and 27 per cent of the study area were
under low, moderate and high erosion risks, respectively. Soil loss computed for
both potential (28 tons/ha/yr) and actual erosion risks (24 tons/ha/yr) by CORINE
model integrated with GIS and RS techniques proved efficient arid inexpensive in
generating soil erosion risk maps. This research can be helpful in improving land
management and soil conservation for the areas of high erosion risk.
