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Applying RS and GIS for Soil Erosion and Sediment Estimation by MPSIAC Model - A case study of Kenesht watershed in Kermanshah, Iran

After sediment estimation in each of the sediment homogeneous units and according to the table number1 sediment production estimation was done for the hydrologic units. The result of the calculation is shown in table 2.

Table (2) the calculations of the sedimentation in the hydrologic units with using the score of homogeneous score

After this with regard to the standard table of MPSIAC, erosion and sediment classes was determined according to the model and the result are summarily listed in table 3.

Table(3)Soil erosion classification and sedimentation rate in Kenesht watershed

By noticing the results of the model in sediment homogeneous units the estimated sediment yield was 74305.147 ton per year in Kenesht watershed.

2- The sediment estimation by using the model data according the score of hydrologic units:
The MPSIAC model was run in hydrologic units of the area under study as homogeneous units and calculated the produced sediment in each of the units. The results were shown in table 4.

Table (4) Sediment yield estimation in Kenesht watershed according to the hydrologic units units

After the estimation of the sediment production in each hydrologic units, soil erosion classes and sedimentation was determined according to the standard table for model MPSIAC and the result were summarily shown in table 5.

Table(5) Soil erosion classification and sedimentation rate in Kenesht watershed

With regard to the results of the model execution in hydrologic units, the sediment yield of the area is estimated at 66076.18 tones per year in Kenesht watershed.

Conclusion and discussion
MPSIAC model is used widely for qualitative and quantitative estimation of soil erosion and sedimentation in executive and research units. There are main problems in the use of this model. One of the biggest problems is using the inhomogeneous area for sediment estimation (Nikkami, 2003).

In order to investigate this matter Kenesht watershed area of Kermanshah which by meeting the criteria in the model and the suitable conditions, 184 homogeneous units was found and MPSIAC model was performed in each of the units.

The results showed that the amount of sedimentation in each homogeneous unit was estimated 1.92 to 26.09 tones per hectare and the specific sediment of Kenesht region is 5.18 tons per hectare per year and the sediment yield of the region was 74305.47 tons per year. But the performance of the model in hydrologic units as homogeneous area (traditional method for use of MPSIAC model) showed the produced sediment is between 3.45 to 5.37 tons in hectare per year and the specific sediment of the region is 4.61 tons in hectare per year and the sediment yield of the region is estimated at 66076.80 tons per year. Also the specific sediment distribution of the hydrologic units by the use of the estimation method of the sediments in homogeneous units is 3.13 to 8.36 and with the use of hydrologic units it is 3.45 to 5.37 tons in hectare pre year.

Comparing of the above values shows that the performance of the model for sediment estimation in homogeneous units is better than traditional method. Distribution of sediment yield and its amount in each homogeneous unit is exactly and sediment production range is from 2 to 26 tons per hectare. But the estimated specific sediment of the hydrologic units as homogeneous units is 3.45 to 5.37 tons per hectare per year and shown an average sediment production and does not show careful distribution of erosion and sedimentation.

After the estimation of the sediments in each of sediment homogeneous units we classified the soil erosion and sedimentation amount according to MPSIAC models to erosion class 1 (very low) and II (low) didn’t exist and the average sedimentation was classified as very high noticing table 2 shows that 37% of the whole area has an average potential of sediment production and 8% of the region's area has a very high potential of sediment production. 55% of the region was classified as high class of sedimentation areas.

The classification of potential of soil erosion and sedimentation in hydrologic units showed that only 3 percent of the region's area has low potential of sediment production and the rest of the region has an average potential of sediment production.

The comparison of the qualitative soil erosion rate of the region with the maps of sedimentation rate from performing the model in sediment homogeneous units (fig.5) and hydrologic units (fig.6) shows that there isn't a great difference between the qualitative erosion rate map and sedimentation rate intensity distribution map gotten from sediment units. But it is very different from the sedimentation rate map in hydrologic units.

Acknowledgements
The authors profoundly are grateful to Kermanshah Academic Center for Education, Cultural and Research (ACECR) and the general governor's office of Kermanshah Province for supplying valuable information and assistance.

References

Ahmadi, H., (1999), Applied Geomorphology, Vol.1, Water Erosion, University of Tehran Press, 3rd Edition, 688pp.
Barkhordari, J. and M. Zare Mehrjerdi, (2006), Importance of GIS ability in erosion and sediment study of sub basins dependent, 2nd Soil and Water resources management and watershed management National Conference, Kerman, 1167-1172p.
Bayramin, I., O., Dengiz, O. Baskan and M.Parlak, (2003), Soil erosion assessment with ICONA model: Case study, Beypazari area, Turk. J. Agric. For.,( 27):105-116.
CSIRO. (2003). Australia advances, soil cancer, series eight, Internet, p1.
Gumel, S., (1996). Manual of soil and water conservation practices. Oxford and IBH publishing co.pvt. Ltd, New Delhi.
Hadiane amri, M.A., S.R. Mousavi, K. Solimani and F. Bayat, (2005), Soil Erosion and Sedimentation Rate Estimation using MPSIAC and EPM Models, 9th Iranian Soil Science Congress and 3rd Erosion and Sediment National Conference, Tehran, 708-709p.
Jafari, M. (2002). Quantity and Quality Estimation of Soil Erosion and Sedimentation in Chikhab River Basin using GIS, MSc. Thesis, Khajeh Nasire Toosi University, Tehran, 112 pp.
Landi, A. and M. Taheri, (2006). Using RS, GIS Systems and MPSIAC Model to produce Erosion Map and to Estimate Sedimentation, 2nd Soil and Water resources management and watershed management National Conference, Kerman, 1444-1452p.
Nikkami, D. (2003). Technical Release of MPSIAC Model Researches Application in GIS, Soil Conservation and Watershed management research Institute, No.82/122, 39pp.
Ownegh. M. (2003). Land use planning and integrated management of natural hazards in Golestan Province, In: Seminar on flood hazard prevention and mitigation, 15-16 January, (2003), Gorgan, Iran, Abstract, p9.
Pilessjo, p., (1992). GIS and remote sensing for soil erosion studies in semi-arid environment, Wllin & Daholm Boktr, B Refahi, H. (2004). Water Erosion and Conservation, University of Tehran Press, 4th Edition, 671pp.