Impacts of Warming on Frozen Soil Permeability over the Ohio River Basin through Recession Flow Analysis

There has been preliminary research into the use of recession flow analysis of catchment areas to measure permafrost thawing rates due to warming. These results indicate a correlation between changes in permafrost depth and coverage and recession flow data in regions that support frozen soils. Here, we aim to test this hypothesis in the Ohio-Tennessee combined river basin--a snowmelt-dominated watershed in the US to further generalize these relationships. The Ohio-Tennessee River Basin in North America covers a large area in the Midwestern United States, from the Appalachian range to the Mississippi River basin and from the Great Lakes region to just south of Tennessee. The basin covers 189,422 square miles (490,600 km2), the 8th largest in the US, with the 2nd largest discharge rate. The USGS has a network of streamgage sites throughout the Basin that have discharge flow rates from as far back as 1933, well before the current warming period that began approximately in the 1980s. Having such an elaborate dataset will prove to be valuable for demonstrating the efficacy of recession flow analysis in catchment areas that lie below subarctic latitudes (below 50°N latitude). Changes in recession of the streamflow (drainage of groundwater) due to warming should be reflected in higher permeability of frozen soil due to lower ice content. Recession flow analysis of seventy-year long streamflows from eleven streamgages spread throughout the Ohio-Tennessee River basin showed decreasing trends in nine gauges for permeability over time with the greatest changes coming from streamgages within the largest sub-basins and the strongest trend correlations due to latitude. In the future, further research goals may include an analysis over other river basins that are more affected by frozen soil in higher latitudes to further test the effects of latitude on results. Additionally, running analyses of air temperature and snow depth using mechanistic modeling (with process-based land surface models) could provide more information on the overall shift in climate of a basin area.