Determination of most appropriate distance between water diversions on skid trails in the mountainous forest, north of Iran

Abstract

Logging operation leads to increased runoff and soil loss on skid trails. This study was conducted to evaluate the appropriate distance among water diversions in skid trails. Surface runoff and soil loss were studied on skid trails in Nav district (North of Iran) after each rainfall event. Two skid trails were selected in this study. Two levels of slope (10, 31%) and three distances among water diversions (25, 50, 75 m) were applied in three replications. All samples were taken after each storm. Surface runoff and soil loss were lower on the smaller plots. Results showed that there was a significant difference between soil loss and surface runoff of different distances among water diversions in 31% mean slope (p ≤ 0.05). While on skid trails with 10% mean slope, there was no significant difference in surface runoff and soil loss. Furthermore, on skid trail with 31% mean slope, 50 m was an appropriate distance among water diversions. The results of our study confirm that slope steepness is a primary factor in controlling surface runoff and soil loss on skid trails. Therefore, reducing skid trail slope during construction and rehabilitation of these trails is recommended to decrease surface runoff and soil loss in forest operations. ► Skid trail construction should be limited to less than 20% slopes. ► A key factor in erosion and runoff control for skid trails is surface protection (such as various types of water diversions). ► Limiting the sedimentation in streams (with water diversions) is essential to prevent water quality degradation.