Gully erosion is an important environmental and food security issue that the globe is grappling with, particularly in developing nations. This study aimed to understand valley bottom gully erosion processes using field measurement and
modeling approaches. This research improved our understanding of the controlling factors and rate of gully head erosion and provided an efficient strategy for identifying gully erosion hotspot areas. Moreover, the study provides insight into how variations in soil type such as Nitisol and Vertisol lead to variabilities in the soil morphology and hydrology, resulting in variations in gully head retreat rates. Finally we have developed a new model called Gully Erosion by Headcut Migration (GEHM) that accounts for various environmental and climatic factors and model gully head erosion at a landscape scale. This thesis's findings could be used to design a better and more informed gully management strategy at the valley bottom.