ABSTRACT: Evaluating the sediment retention function of wetlands in central British Columbia, Canada.

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It is well-documented that one function of a wetland is to maintain a steady flow of water and sediment from land surfaces to other waterbodies. Yet, despite this known fact about wetlands, our understanding of this function is limited. Much of the quantitative research has focussed on the storage of sediment in wetlands under natural conditions or immediately following a disturbance. Information is currently lacking regarding the variability of a wetlands€TMs sediment storage function over time, and the impact of increased sediment delivery on this function. To address this issue, two wetlands in the Quesnel River Basin (central British Columbia, Canada), whose surrounding catchment areas were significantly logged, are being studied. Historical forestry practices were selected as a mechanism that potentially increases the amount of sediment transported through the wetlands. Sediment cores were collected in the summer of 2009 from both wetlands as well as their adjacent lakes to determine the relative proportion of sediment retained by each feature in years prior to, during and following forestry practices. Analysis of radionuclides (Pb-210 and Cs-137) will be carried out to determine core chronology and sedimentation rates. Other proxy indicators (magnetic susceptibility, loss-on-ignition, particle size distribution, carbon-tonitrogen ratio, and geochemical indicators) will be used to assess the wetland filtration over time, and to trace the movement of allochthonous material through the catchment. Climate data will also be examined to determine whether fluctuations in sedimentation rates are explained better by climatic factors (e.g. precipitation, temperature).

Bibliography of Canadian Geomorphology