Variability of Bed Load Components in Different Hydrological Conditions

Abstract

Study Region: The Educational and Research Forest Watershed of Tarbiat Modares University (Kojour), North of Iran. Study focus: The present study was carried out in order to assess the temporal variation of amount and characteristics of bed load in different hydrological conditions. Towards this attempt, we measured the bed load and discharge using a standard flume at the watershed outlet in different temporal and hydrological conditions (from July 2011 to June 2012). New hydrological insights: We found that the amount of the minimum, the mean and the maximum bed load were 3 × 10−8, 6.15 × 10−4± 7.17 × 10−4 and 4.38 × 10−3 kg s−1, respectively. The minimum, the mean, and the maximum discharge were also 60, 334 ± 215.56 and 780 l s−1, respectively. In low discharge conditions during summer, the fine grain sediments had the largest amount of bed load sediment. Coarse and medium-grained sediment transportation was higher in autumn and the early winter consistent with the occurrence of extreme rainfall and flood flows.

Keywords

• Bed Load Texture
• Bed Sediment Granulometry
• Hydrological Variability
• Sediment Load Ratio
• Sediment Transport
• Kojour River