Analyzing temporal and spatial scale effect on sediment yield of micro-watershed in Sanganeh area

Analysis of measured soil erosion data and its variability are critical for advancing erosion science, evaluating soil erosion models, and designing erosion experiments. The present study aimed to evaluate the measured sediment yield data at micro-watershed in Iranian semi-arid rangeland. Towards this attempt, five micro-watersheds with different size (1000 m2-17000 m2) were gauged in Sanganeh watershed, Khorasan Razavi Province, Iran. Storm-wise runoff and sediment was collected at the outlet of each watershed. In this study, sediment yield from micro-watersheds for 55 events over the years 2006 to 2016 were compared and evaluated. The results showed that the maximum of sediment yield were transported in spring due to high rainfall intensity, sediment availability and insufficient vegetation growth. The results also, indicated that mean sediment yield can be changed by a single event (high return period), because approximately a 50% of the sediment yield is produced by only a 7.3% of events. Finally, in current study, a decreasing non-linear relationship between special sediment yield and watershed size was founded.