Critical Thresholds for Sediment Mobility in an Urban Stream

• Main Author: Martin, Ross H
• Format: Others
• Published: Digital Archive @ GSU 2011
• Subjects: Sediment transport; Fluvial geomorphology; Shields stress; Geography; Geology
• Online Access: http://digitalarchive.gsu.edu/geosciences_theses/37; http://digitalarchive.gsu.edu/cgi/viewcontent.cgi?article=1036&context=geosciences_theses

Bed load transport measurements were made in a small urban stream in Decatur, GA, from which thresholds for motion were calculated using methodologies from the published literature. These methodologies are discussed in terms of their limitations and assumptions. Mobility frequencies were calculated for single grains of each grain size fraction to illustrate the transition from size selective transport to equal mobility. In general, urban streams behave differently than many gravel rivers in non-urban settings because of differences in the availability and character of sediment sources and altered flow hydrographs. This comparison allows for discussion about the way sediment is transported in urban streams versus typical gravel-bed, armored channels.