Cumulative effects on sediment and associated chemical fluxes at the landscape scale: the role of geomorpological connectivity

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One of the current research themes in environmental science is how natural and anthropogenic pressures or stressors - such as climate change, land-use activities like forestry and mining, and natural events like wildfires - affect water resources and aquatic ecosystems. This interest is driven by the recognition that most, if not all, water bodies are affected by multiple stressors (often termed cumulative effects) that impact water quantity (e.g. water flows) and water quality (e.g. chemistry, sediment concentrations). The objective of this research project is to determine the cumulative effects of multiple stressors on the environment by focusing on the Quesnel River Basin (QRB, ca. 12,000 km2) in central British Columbia. The overall research project will specifically focus on how geomorphological connectivity (e. g. linkages between land and rivers, and linkages within channels) influences the transfer of sediment and associated chemicals - like trace metals (i.e. arsenic, copper, zinc), nutrients (e.g. phosphorus) and particulate carbon - due to stressors acting in the QRB. One project will evaluate the role of storage elements (specifically glacial forefields, riparian buffers, floodplains, and channel beds) in controlling how sediment and associated chemicals move through landscapes that have been influenced by climate change and land-use activities. In particular, this project will determine if such storage elements attenuate and/or modify material flows and fates. A second project will employ a nested monitoring program in conjunction with sediment tracers, to follow the movement of sediment and chemicals downstream of specific land-use activities such as agriculture, forestry and mining. A third project will use existing spatially distributed models to examine the role of geomorphological connectivity on sediment and associated chemical responses to stressors at the watershed-scale, utilizing the empirical information obtained from the first two projects and an existing GIS platform available for the QRB. The work will provide an improved understanding of how watersheds respond to cumulative effects in a rapidly changing world, which will help to protect water resources and aquatic habitats in Canada.