In-channel surficial fine-grained sediment laminae. Part I: Physical characteristics and formational processes

✍ Scribed by I. G. Droppo; M. Stone

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 957 KB
• Volume: 8
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.3360080202

✦ Synopsis

An in-channel surficial depositional feature (surficial fine-grained laminae) composed of loosely bound fine sediment deposited during low flow conditions has often been observed in river systems in south-western Ontario. The physical characteristics of this feature have been determined by a direct observation image analysis system. This sediment consists primarily of flocculated fine-grained material. The size distributions of surficial fine-grained laminae and suspended sediment were not significantly different. Each distribution is bimodal in nature and shows a characteristic grain size deficiency in the 4-5 pm size range. This observation suggests that flocculation and not low discharge or low competence is the dominant mechanism for the formation of surficial fine-grained laminae under conditions of low flow in fluvial systems of south-western Ontario. A quantitative assessment of this feature shows its potential importance as a source of fine-grained sediment and associated contaminants for downstream transport.