High-Resolution Record of Upper Mississippi River Flood Responses to Holocene Climate Change

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The general objective of this research is to examine the history of alluvial sedimentation of the Upper Mississippi River (UMR) to advance our understanding of how climate variability influences the magnitudes and timing of floods on the main channel of the UMR in western Wisconsin. This mid continent site contains a nearly continuous alluvial record that extends nearly 10,000 years and provides a unique opportunity to examine the history of long- and short-term extreme flow events in this important watershed. The specific goals of this research are to: 1) obtain high-resolution records that can help reconstruct Holocene floods in the main and secondary channels of the Upper Mississippi River (UMR); 2) quantitatively link the flood regime of the main channel to independent paleoclimate proxies obtained from other researchers; 3) quantify and contrast the response of the UMR system to extreme hydrologic events during abrupt climate change and gradual climate change; 4) quantify the response of flood hydrology to the relative changes in climate change (i.e., warmer/wetter, warmer/drier, etc) inferred from proxies. These specific goals will be achieved by a combination of field, laboratory, statistical, and modeling analyses.The research is important because changes in the frequency or intensity of extreme river flows have the potential to produce major impacts on both human society and the natural environment. Instrumental records are too short to adequately determine how climate changes fully influence extremes in flow hydrology on large river systems such as the UMR. Results from this research will help us understanding how terrestrial hydrologic systems respond to changes in global scale atmosphere circulation. The results also should be useful for understanding the relationship between changing climate and recurring extreme hydrologic events.