| dbo:abstract
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- Legacy sediment (LS) is depositional bodies of sediment inherited from the increase of human activities since the Neolithic. These include a broad range of land use and land cover changes, such as agricultural clearance, lumbering and clearance of native vegetation, mining, road building, urbanization, as well as alterations brought to river systems in the form of dams and other engineering structures meant to control and regulate natural fluvial processes (erosion, deposition, lateral migration, meandering). The concept of LS is used in geomorphology, ecology, as well as in water quality and toxicological studies. LS is distributed in spatially heterogeneous ways throughout a landscape and accumulates to form various landforms. It can progress through the fluvial system through facies changes from hillslope colluvium, to floodplain and wetland alluvium, to fine-grained lacustrine and estuarine slackwater deposits. The temporal nature of LS is time-transgressive, meaning that initiation and peak rates of deposition can take place at different times within a fluvial system, as well as at different times between regions. The intermittent transport of LS can be thought of as a cascading system that reworks LS deposits from hillslopes, into channels and onto floodplains, such that anthropogenic sediment will be mixed with and non-anthropogenic sediment. River systems record past and present imprints of anthropogenically-forced changes to the environment. LS is an element of change in this context, as it drives fluxes of energy and matter (connectivity) through fluvial systems and provides indication of past land-uses and river dynamics that can inform future trajectories of river response. In this sense, acknowledging the concept of LS can benefit informed policy development in stream restoration, water quality and sediment budget management, protection of aquatic ecosystems, and flood risk. Moreover, the implications of legacy effects associated with anthropogenically modified sediment dynamics are critical in the context of ecosystem services. (en)
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| rdfs:comment
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- Legacy sediment (LS) is depositional bodies of sediment inherited from the increase of human activities since the Neolithic. These include a broad range of land use and land cover changes, such as agricultural clearance, lumbering and clearance of native vegetation, mining, road building, urbanization, as well as alterations brought to river systems in the form of dams and other engineering structures meant to control and regulate natural fluvial processes (erosion, deposition, lateral migration, meandering). The concept of LS is used in geomorphology, ecology, as well as in water quality and toxicological studies. (en)
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