Pavlowsky This research project will investigate the geochemical and geomorphic processes that determine the spatial variability of the sedimentation of metal contaminants in a floodplain. The study area is the Blue River watershed of the Upper Mississippi valley zinc and led mining district (Wisconsin). The study area affords the research benefits of a relatively simple physical landscape and a concentrated period of metal contamination (1900-1920). The research design calls for 1,310 samples to be taken from 5 cross-sections, 4 point bars, and several active-channel locations selected strategically according to geomorphological criteria. The stratigraphy and geochemistry of the floodplain deposits will be mapped, and the sediment-metal associations will be identified. The results will be used to calibrate watershed-scale models of contaminant dispersal and to identify specific floodplain locations that have the highest potential for toxic effects or remobilization. The research promises advances in two dimensions: a clearer understanding of sediment residence time and in situ chemical alterations to floodplain contaminants; and better predictions of the dispersal of metal contaminants from point sources to both proximal and distal floodplain sinks. The combined longitudinal-lateral study addresses fundamental gaps in our understanding of toxic metal storage and remobilization in watersheds, and it should provide information important for future environmental management.
