IAPRS & SIS. Vol.34, Part 7, “Resource and Environmental Monitoring”, Hyderabad. India,2002 
  
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Figure 1. Location of the Study Area 
Geologically its comprises of two main geological formations 
i.e. Tertiary Basalts and Sedimentary Formations of Pre- 
Cambrian age. The sub-basin rocks are covered by thin (0.5 m) 
to thick (10 m) layer of soils, which are divisible into two 
major groups i.e. red loamy soils and medium black soils. Land 
use pattern of the area is very complex comprising of forest, 
agriculture, shrubs and barren land. The relief varies between 
668 and 1038 m from the mean seal level. The change in 
morphological character from hill crest to valley bottom of the 
basin is largely responsible in the change in behavior of water 
flow between hillslope and foot slope. The entire sub-basin is 
divisible into as many as six altitudinal zones ranging from less 
than 700 m to more than 100 m. The mean annual rainfall of 
three different stations is given in the following Table 1. 
  
  
  
Sr. Name of the Stations Mean Annual 
No. Rainfall (mm) 
E Khanpaur 1729.70 
2. Kankumbhi 5936.80 
3 Jamboti 2291.10 
  
  
  
  
  
Table 1. Mean Annual Rainfall of the various Raingauge 
Stations in the Study Area 
The average total annual rainfall for the catchment of this sub- 
basin is high often exceeding 3300 mm. The rainfall is not 
evenly distributed throughout the year as well as throughout the 
sub-basin. It receives maximum rain of 36.5% of the total 
annual rainfall in the month July and 27.3% of the rainfall 
during August, which is the second important month. About 
21.6% of the rain are received during the early part of the 
southwest monsoon season i.e. in June. 
2. METHODOLOGY 
The Universal Soil Loss Equation (USLE) is the best known 
and most widely used soil erosion model. USLE was developed 
to estimate interrill soil losses over extended time periods. The 
limitation of this model is that, it does not estimate deposition, 
sediment yield, channel erosion, or gully erosion. The soil loss 
is computed by the expression: 
A 7 R*K*L*S*C*P (1) 
  
Where, L,S, C,P are all dimensionless coefficients 
R (rainfall erosivity factor) is dependent on the parameter EI, which 
is the product of kinetic energy of the storm and the maximum 30 
min intensity 
K (soil erodibility factor) is a function of the percentage of silt, and 
coarse sand, soil structure, permeability of soil and the percentage of 
organic matter. 
L (slope length factor) is defined as the ratio of soil loss from a 
particular slope length compared with a unit plot length (22.13 m) 
with all other conditions. 
S (slope steepness factor) is a function of the actual slope. 
C (Crop management factor) is defined as the ratio of soil loss from 
tilted, continuous fallow 
P (erosion control practice factor) takes into account the effect of 
conservation practices such as contouring, strip-cropping and 
terracing erosion. 
The equation groups the numerous interrelated physical and 
management parameters that influence the erosion rate under six 
major factors, of which site specific values can be expressed 
numerically (Singh et al. 1981). 
Generation of Base Maps and Thematic Maps 
For the present study, the toposheet (1:250,000) was used to prepare 
the base map in GIS environment. The GIS software, ILWIS 
(Integrated Land and Water Information System) was used for the 
generation of the base maps of sub-basin boundary, contours and 
drainage etc. Different thematic maps such as land use and soil 
texture maps were prepared using the above base maps (Figure 2 and 
Figure 3). 
  
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Zara Lael 
  
  
Figure 3. Soil Texture Map of the Study Area 
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