Biological Effects of Fine Sediment in the Lotic Environment

/ Although sedimentation is a naturally occurring phenomenon inrivers, land-use changes have resulted in an increase in anthropogenicallyinduced fine sediment deposition. Poorly managed agricultural practices,mineral extraction, and construction can result in an increase in suspendedsolids and sedimentation in rivers and streams, leading to a decline inhabitat quality. The nature and origins of fine sediments in the loticenvironment are reviewed in relation to channel and nonchannel sources andthe impact of human activity. Fine sediment transport and deposition areoutlined in relation to variations in streamflow and particle sizecharacteristics. A holistic approach to the problems associated with finesediment is outlined to aid in the identification of sediment sources,transport, and deposition processes in the river catchment. The multiplecauses and deleterious impacts associated with fine sediments on riverinehabitats, primary producers, macroinvertebrates, and fisheries are identifiedand reviewed to provide river managers with a guide to source material. Therestoration of rivers with fine sediment problems are discussed in relationto a holistic management framework to aid in the planning and undertaking ofmitigation measures within both the river channel and surrounding catchmentarea.KEY WORDS: Sedimentation; Fine sediment; Holistic approach; Ecologicalimpact; River restoration