Investigation of Cobble Bar Morphology and Sediment Texture in an Arctic River

• Main Author: Shoen, Kyle
• Other Authors: Sawyer, Audrey
• Format: Thesis
• Language: English
• Published: The Ohio State University 2024
• Subjects: Earth Science; Morphology; Sediment Texture; Arctic; Grain Sizing; Abisko
• Online Access: https://kb.osu.edu/handle/1811/104258

Different methods are widely used to map grain size distributions in rivers, and a comparison of these methods could give better insight into the fluvial geomorphology of Arctic rivers, which are inaccessible to sampling over much of the year. This study focuses on the Miella River near Abisko, Sweden (latitude 68N), which has ice break-up and flood events. I analyze grain size across six geomorphic zones that were identified along a characteristic cobble bar and adjacent riverbed. As part of this analysis, I compare manual Wolman pebble counts and ground-based photographic analysis of sediment textures. Ten evenly scattered ground-based photographs from each of the six zones were taken approximately 1 m from the surface level and were analyzed using BASEGRAIN, an automatic MATLAB-based object detection software. BASEGRAIN was rapid to implement compared to Wolman pebble counts but challenging to implement in submerged portions of the channel, leading to inaccuracies in grain size estimation underwater. Both BASEGRAIN and Wolman pebble counts identified distinct sediment texture differences between zones. This study contributes to a larger effort to shed new light on geomorphologic and sediment transport processes of the Miella River and will help guide the selection of different grain size analysis techniques in future Arctic river studies. McKenzie-Brecher Undergraduate Research Grant from Byrd Polar and Climate Research Center GSA North Central Section Undergraduate Research Grant No embargo Academic Major: Earth Sciences