GIS to Create Maps Based on the Bergsma Model for Gully Erosion Estimation Using DEM: A Case Study for Qarahanjeer, Kirkuk, Iraq

Gully erosion is a serious environmental problem that threatens soil sustainability, especially in arid and semi-arid regions like Qarahanjeer in Kirkuk, which spans an area of 676 km². The main research problem is the lack of studies and effective methods to determine the extent of gully erosion. To meet this challenge, this study used the Bergsma (1986) model and GIS techniques to estimate gully erosion based on digital elevation model (DEM) data from the ALOS PALSAR program. The main objective of the study is to evaluate the applicability of the Bergsma model in mapping gully erosion risk areas in the Qarahanjeer region and to verify its effectiveness using field observations. The results revealed the levels of gully erosion. High erosion was the predominant category, comprising 54.692% of the research area, represented by categories from 1501 to 2700. Moderate erosion (21%) occurred in transitional zones, characterized by augmented fluvial energy and vegetative cover (1001 to 1500). Despite very limited areas (12.47%) categorized (2701 to 3700), severe erosion (0.69 %) categories (3701 to 4700) assessments signify significant degradation, as these operations disrupt natural drainage patterns. Also, recommended that depressions be dug in the basin estuaries to collect water, particularly surface runoff for use, and to utilize high-resolution spatial data to estimate erosion. Applying research and recording geomorphological changes with GIS and remote sensing.