Sub-Watershed Map of Shui-li River Watershed 
( Landsat TM band 4,3,2 ) 
  
Figure 1. Landsat TM image for study area 
  
  
climate plant 
process in agriculture production and to estimate the impact of soil erosion on 
resource productivity (Putman J., 1988). 
Many researches concluded the modified slope factor has the characteristics of 
complexity and most hydrologists suggested to put the value of one as slope factor 
when using RUSLE model. This paper also assign the value of one to the slope factor 
of RUSLE model. 
USLE (Universal Soil Loss Equation ) 
USLE model has been developed through 40 year’s experiments in USA. 
Parameters in this model were extracted from standard field scale. The standard site 
is 22.13 meter long with average 9% in slope, and plowing toward up and down 
direction, composed by uniform soil profile. The equation can be shown as: 
A = RKLSCP 
where : 
A —computed average soil loss per unit of area, expressed in units selected 
for K and for period selected for R. In practice these are usually so 
selected that they compute A in tons per acre per year. 
R — rainfall and runoff index- the number of rainfall erosion index units plus 
s factor for runoff snowmelt or applicde, where such runoff is significant, 
138 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996