1. Shedding and size distributions of suspended sediments in an urban watershed
- Author
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Ahn, Jong Ho
- Abstract
Particle size spectra of suspended sediment eroded from the Santa Ana River, a human-impacted urban river in southern California are investigated to consider fractal behaviors in suspended sediment transport. Widespread urbanization has fueled hydrological change of the watershed over four decades, showing significant increases in storm water runoff with decreases in instantaneous suspended sediment concentration. In-site observation of particle size distributions (PSDs) during three storm studies reveals two transport regimes (flow-controlled or bed- controlled) depending on whether average particle size increase (flow-controlled) or decrease (bed-controlled) with flow rate. Despite their complexity, the observed PSDs exhibit power-law mass-size statistics, and satisfy fractal (power-law) scaling in a very robust manner. The evolution of PSD to a stable form with asymptotic behavior in suspended sediments suggests that shedding of suspended sediments in urban watershed environment system has its own selforganized characteristics wherever the sediment source come from.
- Published
- 2012
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