CHANGES IN GEOMORPHIC EQUILIBRIUM ON FURNACE RUN, SUMMIT COUNTY, OH

Furnace Run, a tributary to the Cuyahoga River, Summit County, Ohio, has experienced pronounced morphologic changes since 2003. The aim of this on-going study is to examine and interpret present-day and historical geomorphic conditions on Lower Furnace Run in order to explain changes in stream equilibrium conditions. Equilibrium conditions are altered by changes in land use and precipitation, and the study hypothesizes that climatically-induced changes in precipitation are the leading cause of disequilibrium conditions on Lower Furnace Run. GIS analysis of recent and historical aerial photography, stream gauging, channel mapping, and statistical analysis of historical precipitation and discharge data are being used to address the hypothesis. Two out of three nearby rain gauge stations show a statistically significant increase in precipitation after 2002 using Two-sample T-tests (α=.05) on ten year sampling intervals. Four out of five stream gauge stations within the Cuyahoga River watershed show a statistically significant increase in discharge after 2002 using Two-sample T-tests (α=.05) on ten year sampling intervals. GIS analysis of eleven historical aerial photographs ranging in date from 1938 to 2010 show the channel changing from a sinuosity of 1.40 in 1938 to a straightened channel in the 1950’s with sinuosity approaching 1.00. Sinuosity steadily increases from 1.02 in 1959 to 1.21 in 2000. Sinuosity increases to 1.23 in 2005 and to 1.36 in 2010. The lateral movement of cut banks was analyzed along seven transects on the photos. Cut banks along the stream eroded at a rate of 0.08 meters per month from 1992 to 2000. Erosion rates increase to 0.44 meters per month from 2006 to 2010. Field observations suggest little to no change in channel geometry prior to the onset of flood events beginning in July 2003. Changes in channel geometry and erosion rates coincide with increases in precipitation and discharge in northeastern Ohio, however the role of development near the headwaters of Furnace Run is under further investigation. The understanding and characterization of changes in stream morphology are important in planning for future infrastructure improvement projects involving the bridges that pass over the stream, as well as anticipating the impact on the agricultural land surrounding the stream.