Characteristics and Causes of Gully Erosion in Iran

摘要

A research plan is going to start to study the characteristics and causes of gully initiation. To set up its methodology, a questionnaire was designed and tested by experts in the field in 1998 and 1999 in five provinces with different physical and socio-economic conditions. The pre-results indicate that gullies are initiated in different ecological and climatological conditions. Their view plans are dendretic with U-shaped cross section and medium size with respect to their depth. The vertical profile of the headcuts is dominantly vertical, that is the activity of surface runoff is important. The results reveal that the important factors in gully initiation are deterioration of vegetation cover, flood and rainfall intensity and mismanagement of watersheds. Important on site damages are disconnection of rural roads and bridge breakage, land scoring, recession of water table, immigration of rural people and movement of the location of villages. At this stage it seems that the combination of high intensity rainfall with ground surface disturbance by road construction and deterioration of native vegetation cover are the most important factors for gully initiation. Surface runoff would be the dominant hydrological process in gully development.