CGRG Bibliography of Canadian Geomorphology
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Author : Droppo, I. G.; and Ongley, E. D.
Date : 1989
Title : Flocculation of suspended solids in Southern Ontario Rivers
Publication : Sediment and the Environment. Proceedings of a Symposium held in Baltimore; Maryland. International Association of Hydrological Sciences, Publication. Washington, DC.
Issue : 184:
Page(s) : 95-103
Abstract
Suspended solids play a primary role in fluvial transport of hydrophobic contaminants. Evidence suggests that in many rivers primary particles are frequently transported as flocs within the aquatic medium. The changes in floc size and shape between two sampling sites during the summer low flow period and in a storm event were examined for the Oakville Sixteen Mile Creek in southern Ontario, Canada. Samples were collected directly in settling chambers and flocs were analyzed by microscopy, photography and digitization. Bacteria associated with flocs were quantitated by epifluorescent microscopy after 1.0 micrometer filtration. While there were fewer flocs than primary particles in suspension (flocs composed 10-27% of the total number of particles), the flocs comprised 92-98% of the total suspended solid volume. There was no significant difference in floc size between sampling sites, one of which was in a rural, forested area and the other in the harbor of an urban area. Mean floc area decreased from 173.5 sq micrometers during a dry period to 94.97 sq micrometers after a high intensity rainstorm of 45 minutes followed by light rain. It was concluded that while the digitizing method has some limitations, especially for grain size distributions, it is useful in evaluating physical and biological controls over flocculation
Bibliography of Canadian Geomorphology