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Comparing Three Approaches to Reconstructing Streamflow Using Tree Rings in the Wabash River Basin in the Midwestern, US

Strange, Brandon M., Maxwell, Justin T., Robeson, Scott M., Harley, Grant L., Therrell, Matthew D., Ficklin, Darren L.
Journal of hydrology 2019
basins, drought, growth rings, models, rivers, statistical analysis, stream flow, variance, watersheds, Illinois, Indiana
Tree-ring reconstructions of streamflow can provide long-term perspectives of flow variability that may be useful in management strategies for water resources. Relative to other portions of the United States, there is a dearth of tree-ring based streamflow reconstructions in the Midwest. The Wabash River is an important water resource in Indiana and Illinois where many sectors rely on it. Here, to better understand the historic hydroclimate within the Wabash River Basin, we reconstructed June–September streamflow for a tributary of the Wabash River using three statistical approaches: the traditional basin approach, and the recently-developed climate-footprint, and drought-reconstruction approaches. Our reconstructions explained 53–71% of the variance for the common period (1941–1984). We find that in our three reconstructions, there are extreme droughts and pluvials that exceed those during the instrumental period, including a sustained five-decade low-flow event in the early 19th century. Overall, we find that the traditional basin approach produced the most robust model but had the shortest reconstruction length of the three approaches, as it requires the predictor chronologies to be derived from within the basin. Our results indicate that there are merits and drawbacks to each approach with the general pattern of sacrificing variance explained for reconstruction length.