ESTIMATION OF SOIL EROSION IN NORTHERN KIRKUK GOVERNORATE, IRAQ USING RUSLE, REMOTE SENSING AND GIS

A quantitative assessment of annual soil erosion by water in the northern part of Kirkuk Governorate, north of Iraq was investigated through integration of remote sensing, GIS and empirical RULSE soil erosion model. The five factors of RULSE model (rainfall erosivity R, soil erodibility K, slope length and steepness LS, crop management C, and practice factor P) were derived from different resources such as field survey, archival data, digital elevation model, and LANDSAT 8 multi-bands imagery. The annual soil erosion loss was estimated by multiplying the five factors in raster format using raster calculator of ArcGIS 10.2 software. The estimated annual soil losses rate for the study area ranges from 0 to 245 (t ha(-1) yr(-1)) with an average of 2 (t ha(-1) y(-1)). The value ranges were classified into four categories: minimal, low, moderate, high soil erosion hazard zones using four classification schema: quantile, natural breaks, geometric, and standard deviation. Due to the similarity of results, the comparison was carried out between two schemas: natural breaks and geometric. The area covered by minimal-low soil hazard zones extends over an area of about 88% and 99% based on geometric and natural breaks schema, respectively. In turn, the moderate-high soil hazard zones cover only very small area (0.3%) based on natural breaks and relatively small area (12%) depending on geometric scheme. In general, both method results indicate that hazard of soil erosion is low in the study area. The spatial pattern of classified soil erosion rate indicates that the areas at moderate to high risk is located in the northeast and very small area in the east, while the minimal to low zones cover the other parts. The obtained results of could be useful to implement soil conservation practices in the study area.