International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004 
F) Calculation of R (sum of the effective factors) and Q values for 
each location 
G) Categorizing different erosion levels 
Based on factors needed to establish the MPSIAC soil erosion 
model, using an A0 color scanner all the hard copy maps were 
scanned and saved in computer with jpeg format. Hardcopy 
topographic sheets were geo-referenced and joined as mosaic in 
UTM map projection system using GCPworks module of 
Geomatica software package (figure 1). All the other hardcopy 
maps and satellite data were then registered on the same image 
and the boundaries of the map categories were then digitized and 
saved in the same file. The contour lines of the digital topographic 
maps were simply imported and saved in the mosaic file and used 
to generate Digital Elevation Model (DEM) of the area. Through 
watershed and vector utility of Xpace module of Geomatica, 
slope, aspect and watershed sub-basins images were produced. 
After statistical analysis of rainfall data, they were used to 
generate digital rainfall model using interpolation techniques. 
Satellite data (figure 2) used to produce two inputs for the model. 
General land use map of the study area was produced using 
maximum likelihood classification algorithm. And land cover map 
was produced using EASI modeling language of Geomatica 
software based on normalized vegetation difference index 
(NDVI). Run off map was also generated. By field survey, and 
based on BLM method the erosion condition map was created. 
The gully erosion factor in MPSIAC model was created through 
SSFG in the BLM method. 
  
  
  
Figure2. Mosaic TM image of the area 
After the preparation and assignment of relative importance 
weights of all effective factors in MPSIAC model, based on the 
following equations and using modeling language of Geomatica 
software package, the final erosion map was produced (figure 3). 
R=X1+ 16.67X2 + 0.2X3 + 0.3X4 + 0.33X5 + 0.2X6+ [20-0.2X7] 
+ 0.25X8 +1.67X9 
X1 through X9 are geology, soil, climate, runoff, topology, land 
cover land use surface erosion and gully erosion factors 
respectively. 
R-sum of the effective factors 
Q=38.77e 5558 
Q-total sediment yield in m*/km"/yr. 
Through this procedure, the final map that shows different level 
of erosion in this area was produced figure 3. 
Erosion rate 
C1 Less 
! EH Medium 
High 
I] 
Very high 
    
  
arr EE sy 
  
  
Figure3. Final erosion map 
3. RESULTS AND DISCUSSIONS 
As it is clear from the figure3, in this area the erosion process is in 
its high rate in the north. That is because of the geology and steep 
slopes and less vegetation cover of that area. In eastern and south- 
eastern part of this area, due to the factors like slope, less dept 
soils, feeding chattels, cultivation in the slopes and the presence of 
marl formation, the erosion rate is high. In south due to 
agricultural activities and fewer slopes the erosion rates are very 
less. Due to high sediment rates in this part of Iran, watershed 
management plans should be actively defined and implemented. 
Results of this study show that remote sensing data in conjunction 
with image processing software packages could be useful to 
estimate erosion rate in watershed sub-basin area. MPSIAC modd 
has shown to be a useful way of estimation total sediment yield 
for arid and semi-arid regions and powerful image processing 
software packages like Geomatica could be efficiently used for 
such multi-layers modeling problems. In the cost and time point of 
view, doing such tasks is less time consuming and cost effective in 
comparison with traditional method of soil erosion studies. The 
importance of this research work is that instead of using GIS 
software, all the spatial analyses were carried out using image 
processing software package 
REFERENCES 
American Geophysical Union, 1977, Research Needs in Erosion 
and Sedimentation, Report of the Committee on Erosion and 
Sedimentation, Hydrology Section, Trans. Am. Geophys. Union, 
58(12): 1075-1083. 
American Society of Civil Engineers, 1975, Sedimentation 
Engineering, ASCE Manuals and Reports on Engineering 
Practice, No. 54, V. A. Vanoni (Ed.), ASCE, New York. 
American Society of Civil Engineers, 1982, Relationships 
between morphology of small streams and sediment yield, Report 
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