Today, soil erosion is considered as one of the important issues of watershed management at the national and global level. Considering that the calculation of erosion and sediment values through hydrometric and sediment measurement stations and direct measurements in different parts of the basins is a costly and time-consuming process.Therefore, finding experimental methods to accurately estimate the amount of erosion and sedimentation of watersheds seems necessary and inevitable.Erosion is a process in which soil particles are separated from their substrate by erosive agents and transported to another place with the help of one of the transfer agents.If the particle separator is wind and refrigerator. It is called wind erosion and glacial erosion respectively.

Water erosion also occurs due to improper land management, destruction of vegetation and lack of water flow control, and causes surface runoff and soil transfer.

Methodology

Zimkan river basin is located in the north of Dalaho city and west of Kermanshah province. This basin is limited from the south and east to the Zamkan Dam basin,from the west to the Piran basin and from the north to the Posht Teng basin and the Lima river basin. The basin is located at the geographical coordinates of 46°4΄ to 46°11 ΄ east longitude and 34°35 ΄ to 34°22΄ north latitude. Among the residential areas in the basin, we can mention the villages of Ghoshchi Bashi, Asiyab Tanureh, Deh Kohene, Seyed Baqer and Reza Ali Farm. The studied basin has an area of 2324 square kilometers and an average height of 2044.42 meters.

In general, there are two methods for measuring erosion and sedimentation; Direct and indirect. Direct methods are carried out using various measuring tools and devices. In these methods, erosion and sedimentation are usually measured in stages and in different ways and their amounts are presented quantitatively.

In this research, two EPM and RUSLE models are compared in order to estimate erosion and deposition, and in this regard, the factors of the two methods are investigated.

The four factors of the EPM model include:

1. Basin erosion

2. Land use

3. Sensitivity of soil and rock to erosion

4. The average slope of the basin

And also the inputs of RUSLE model include:

1. Rainfall erosion factor (R)

2. Soil erodibility factor (K)

3. Slope length factor (L)

4. Slope factor (S)

5. Plant cover agent (C)

6. Soil protection agent (P)

These factors are evaluated. And the soil erosion maps obtained from two models are obtained from the results of the models.



Results and Discussion

In this research, EPM and RUSLE models and RS and GIS techniques were used to determine the erosion intensity and sedimentation potential of the studied basin. And according to the results of these two models, effective factors in erosion were evaluated and scored, and according to the relationship between sedimentation rate and sedimentation rate, the sedimentation potential of the basin was determined. Also, the amount of erosion and its severity were evaluated and its digital map was prepared and drawn with the help of GIS





Conclusion

According to the expected results of the statistical tests by SPSS and GIS software, finally the RUSLE model was chosen as a more reliable model than the EPM model to estimate the amount of erosion and sedimentation in the researched basin, and the EPM model was chosen as the shadow and secondary model. It will be determined after the RUSLE model. Therefore, the aim of this research is to introduce the RUSLE model in the estimation of erosion and sedimentation and finally to provide an optimal and compatible model for the Zimkan river basin, which is located in Dalaho city, Kermanshah province.







Methodology

Zimkan river basin is located in the north of Dalaho city and west of Kermanshah province. This basin is limited from the south and east to the Zamkan Dam basin,from the west to the Piran basin and from the north to the Posht Teng basin and the Lima river basin. The basin is located at the geographical coordinates of 46°4΄ to 46°11 ΄ east longitude and 34°35 ΄ to 34°22΄ north latitude. Among the residential areas in the basin, we can mention the villages of Ghoshchi Bashi, Asiyab Tanureh, Deh Kohene, Seyed Baqer and Reza Ali Farm. The studied basin has an area of 2324 square kilometers and an average height of 2044.42 meters.

In general, there are two methods for measuring erosion and sedimentation; Direct and indirect. Direct methods are carried out using various measuring tools and devices. In these methods, erosion and sedimentation are usually measured in stages and in different ways and their amounts are presented quantitatively.

In this research, two EPM and RUSLE models are compared in order to estimate erosion and deposition, and in this regard, the factors of the two methods are investigated.

The four factors of the EPM model include:

1. Basin erosion

2. Land use

3. Sensitivity of soil and rock to erosion

4. The average slope of the basin

And also the inputs of RUSLE model include:

1. Rainfall erosion factor (R)

2. Soil erodibility factor (K)

3. Slope length factor (L)

4. Slope factor (S)

5. Plant cover agent (C)

6. Soil protection agent (P)

These factors are evaluated. And the soil erosion maps obtained from two models are obtained from the results of the models.



Results and Discussion

In this research, EPM and RUSLE models and RS and GIS techniques were used to determine the erosion intensity and sedimentation potential of the studied basin. And according to the results of these two models, effective factors in erosion were evaluated and scored, and according to the relationship between sedimentation rate and sedimentation rate, the sedimentation potential of the basin was determined. Also, the amount of erosion and its severity were evaluated and its digital map was prepared and drawn with the help of GIS