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Geoscience / DTM
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Assessment of Erosion in Mountain Regions
Application :
In this research the development of the PSIAC Model by two different Methods is undertaked. In first Method all physiographic factors are taken without using Remote Sensing and GIS, and overlaying the nine factors have been done by hand. In this case the catchment with 70000 (ha) is divided to 19 subcatchments, Therefore the averages charectristic of each factor are considered within the 19 subcatchments, and for each physiographic factor, average units are used (See table 3, Fig. 1), Hence a lot of mistakes taked into account. In Second Method most of physiographic factors are taken by Remote Sensign and with the aid of GIS, nine layer maps are overlayed. In this case the catchment is divided to 1700 homogenious polygons (with aid of GIS) (see fig. 2) and for each homogenious polygon PSIAC Model is used. With comparsion to real data (Hydrometry Data Analize) Remote
sensing and GIS could increase the capability of the Model upto 20 percent.
Figure 1: Latian Subcatchment
Figure 2: Latian Catchment Polygons
Conclusions
The evaluation of existing erosion and sediment Models in Mountain erase with variety f physigraphic characteristics without using remote sensing technique and GIS, not only is much difficult but also the estimations has no sufficient accuracy.
The Remote sensing with aid of the Geographic Information System (GIS), by creating much more homogenious polygosn, has sufficient accuracy for evaluation of Models.
References
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Bruwer, H.d. Introduction to Geographic Information
- Goldman, Steven J.Katharine Jackson, Taras A. Burxatynsky. PE. Erosion and sediment conrol Hand Book Mcgraw- Hill 1985.
- Hadley, R.F.R Lai; onstad, C.A. Walling, D.E., Yair, A Recent Developments in Erosion and Sediment Yield Studies, Unesco, 1985.
- Hor, John. A Introduction to Aerial photography, ITC Netherlands 1992.
- IAHS, Erosion Debris Flows and Environment in Mountain Regions 1992
- Walling, D.E. Recent Developmen in the Explanation and prediction of Erosion and sediment Yield, IAHS No. 137, 1982.
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