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Different types of soil erosion including gully erosion occur in many parts of Iran. The west of Iran is further threatened by gully erosion due to its specific physical and climatic conditions. However, few studies have been carried out to study the sediment production of gully erosion in Iran. This research was therefore conducted to measure storm-wise sediment production of gully erosion in the west of Iran. To achieve the study objectives, 48 gullies located in three small watersheds viz. Darreh-Shahr, Abbas-Abad and Hollowsh in Ilam and Lorestan Provinces were monitored. The volumes of gullies were measured before and after 5 rainstorms for Darreh-Shahr and Abbas Abad watersheds and 6 rainstorms for Hollowsh watershed from 2005 to 2007. Sediment production was calculated on storm basis for each gully. The results revealed that the minimum and maximum volumes of gully erosion were 0.002 and 1.010 m³, respectively, for one millimeter of rainfall. The results indicated that soil moisture, percentage of silt and clay, amount and intensity of rainfall and drainage area were the most important factors on formation and sediment production of gully erosion.

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The physical and chemical properties of soil are very different.‌In addition to influences on these properties, these elements also indirectly or directly affect the soils erosive sesitivity.The changes of soil properties is very rapid on the length of slopes. Due to rapid changes, the attention on the impacts these changes on erosive soils is very important. Planners must pay due attention to these properties and also be concerned at soils characteristics at all projection. Texture, structure, rate of organic carbon, EC, pH and moisture of soil, may affect the fertility and erosion of soils. The study area, is located on the northwest slopes of Sabalan mountain, from 38˚.15' to 38˚.30' N, and from 47˚‌.00' to 47˚.38' E between Ahar and Meshkinshar. In this paper, we studied soils erosive properties in relation to the slope elements. The results suggested that slope elements have a major and detrimental role on the chemical and physical properties of soil, erosion and gulling.

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Gully erosion can be considered as one of the advanced and critical forms of water erosion causing the destructors of the large amount of the earth. Identifying the factors that have an important impact in the occurrence of this type of erosion and its zoning can also be considered as one of the essential and important tools for managing and controlling this phenomenon. This study has been carried out with the purpose of identifying the factors affecting on the creation of gully erosion and the stimulation of the possibility of its occurrence in Dyreh catchment. The most effective factors in gully creation are: slope, slope direction, horizontal and vertical curvature of the slope, lithology, distance from waterway, and distance from the road. The land was selected and then these layers were created in GIS. Therefore, in the creation of gully erosion, they were classified based on preferences in order to have a paired comparison in the matrix table. Finally, the act of weighting the functions and overlapping of the layers were done by Arc GIS software and according to the resulting coefficients' hazard zonation map obtained in 6 layers: without risk, very low risk, low risk, medium risk, high risk, and too high risk. The final coefficient of numerical value was defined using the numbers obtained by multiplying the weight of each criterion in the index anywhere between zero and 100. In which the more tendency to 100 indicates as high risk of landslide’s, and the coefficients close to zero indicate that there is less risk and that its occurrence is without danger. The results further showed that %36 of Dyreh basin faces high risk, and too high risk causing the displacement of large volume of soil.    

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Gully erosion affects soil properties in different ways. One of the most important effects of gully erosion is destruction of soil structure and reducing its quality. The objective of this research was to study the effects of gully development on soil properties and quality indices in areas adjacent to the gullies. For this purpose, 15 soil properties and 5 soil quality indices including Integrated Quality Index (IQI), Nemero Quality Index (NQI), Cumulative Rating (CR), and Sustainability Index (SI) were compared between gully wall and outside gully lands in three sites of Ardabil province, northwestern Iran. T-test method with three replications was used for comparison. The results showed that in all three sites, 8 out of 15 soil properties changed near the gully walls, mainly indicating the reduction of soil structure, organic carbon, and S index (slope of retention curve at inflection point) and increasing the Cation Ratio Of soil Structural Stability (CROSS) and soil erodibility index. Also, near the gullies, most of the soil quality indices decreased due to gully development in the study sites. Therefore, gully formation and development in these sites reduced soil quality near the gully walls.