Sediment Dispersal Processes and Anthropogenic Impacts at Rex Lake, Summit County, Ohio
Total Page:16
File Type:pdf, Size:1020Kb
SEDIMENT DISPERSAL PROCESSES AND ANTHROPOGENIC IMPACTS AT REX LAKE, SUMMIT COUNTY, OHIO A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Master of Science Stephanie B. Mitchell December, 2015 SEDIMENT DISPERSAL PROCESSES AND ANTHROPOGENIC IMPACTS AT REX LAKE, SUMMIT COUNTY, OHIO Stephanie B. Mitchell Thesis Approved: Accepted: ______________________________ ______________________________ Advisor Dean of the College Dr. John A. Peck Dr. Chand Midha ______________________________ ______________________________ Faculty Reader Interim Dean of the Graduate School Dr. James McManus Dr. Chand Midha ______________________________ ______________________________ Faculty Reader Date Dr. David Steer ______________________________ Department Chair Dr. James McManus ii ABSTRACT The sediment in Rex Lake, a kettle lake in Northeast Ohio, preserves a record of modern sedimentation processes and past anthropogenic impacts to the lake and its watershed. Rex Lake is connected to a series of kettle lakes and human-made reservoirs that forms the Portage Lakes System, a popular recreational area. Rex Lake is affected by sediment focusing processes and has a wave base of 2 m. Sands and gravels having high dry bulk density and low organic content are present in water less than 2 m deep. Organic mud and calcareous mud are present in water depths greater than 2 m. The acoustic properties of the lakefloor were used to remotely determine differences between sands/gravels and muds. Because of differences in matrix lithology and pore geometry of the organic muds and calcareous muds, this study shows that caution must be exercised when using acoustics to remotely sense lakefloor sediment grain size. The upper 4 m of mud, from the middle of the lake, was cored and measured for physical properties, sedimentology and trace metal content. Four time periods having distinct sediment characteristics were identified and related to changing anthropogenic activities. The Pre-settlement Period characterizes organic mud below 135 cm core depth, having low sediment density, magnetic, and trace metal content. This sediment is inferred to have accumulated while the watershed was forested prior to Euro-American settlement of the area in 1805. In the Settlement Period, between 135 and 70 cm core depth, organic content decreases, magnetic content and sediment density increase slightly, and trace metal content remains low. These sediment changes are inferred to reflect iii increased erosion as the watershed was deforested for agricultural activities. In the Recreation Period, between 70 and 20 cm core depth, organic content decreases to its minimum value whereas the trace metal, magnetic content, and sediment density increase greatly. During this period increased human activity (e.g., boating) resulted in the greatest amount of trace metal contamination to the lake. Trace metal concentration in an area is influenced by the amount and the type of anthropogenic activity. Within Summit County, Ohio more lake sediment pollution occurs in heavily populated areas (urban or industrial) than in less populated (rural) areas. In the Environment Regulation Period, between 20 and 0 cm depth, the sediment has low organic content and declining magnetic and trace metal content. This decline likely reflects a decrease in both manufacturing and industrial output in Northeast Ohio and the effectiveness of the Clean Air (1970) and Water Acts (1972) to limit pollution input to the environment. iv ACKNOWLEDGEMENTS I would like to thank my advisor Dr. John Peck for his guidance throughout the thesis process and for pushing me to be a better overall scientist. I would also like to thank my committee members Dr. James McManus and Dr. David Steer for their input throughout the years. I would like to thank Chris Biro for his help in the field and continuous support through song and dance. Thank you Tom Quick and Elaine Butcher for both their guidance and wisdom. I also would like to thank Carl Medvid for helping me with the seismic processing program. Thank you Portage Lakes State Park for granting me permission to study Rex Lake. I would like to thank my parents and friends for their patience and encouragement, especially during these trying times. Thank you Haenim Cho, Amy Connerley, Gina Filiano, Justin Gilbow, Annie Hartwell, Leslie Hellebuyck, Chad Magilavy, Jay Mannion, Natalie Murray, Charles Spurr, and Zac Strong for the many laughs and hospitality when my apartment lease ran out. I want to give a special thanks to Carlo Rossi, for always being there for me through the good times and the bad times. Last but not least, I would like to thank Diamond Deli for inviting me into their family and for motivating me. I might actually miss this place. v TABLE OF CONTENTS Page LIST OF FIGURES ........................................................................................................... ix LIST OF TABLES ........................................................................................................... xiv CHAPTER I. INTRODUCTION .........................................................................................................1 1.1 Significance of Study ..............................................................................................1 1.2 Physical Setting of Rex Lake ..................................................................................2 1.3 History of Rex Lake ................................................................................................7 1.4 Previous Research ..................................................................................................14 1.5 Present Thesis Study ..............................................................................................14 II. METHODS ������������������������������������������������������������������������������������������������������������������16 2.1 Field Procedures �����������������������������������������������������������������������������������������������������16 2.1.1 Sediment Core Sampling ..............................................................................16 2.1.2 Surface Sediment Sampling ..........................................................................19 2.2 Laboratory Procedures ...........................................................................................19 2.2.1 Magnetic Susceptibility ................................................................................19 2.2.2 Lithologic Analysis .......................................................................................19 2.2.3 Physical Properties ........................................................................................23 2.2.4 Trace Metals ..................................................................................................23 2.2.5 Grain Size Analysis .......................................................................................24 2.2.6 Magnetic Analysis .........................................................................................26 vi 2.2.7 Environmental Scanning Electron Microscope (ESEM) ..............................27 2.2.8 P-wave Analysis ............................................................................................27 2.2.9 Seismic Reflection Profiling .........................................................................29 III. RESULTS .....................................................................................................................30 3.1 Surficial Sediment Distribution ������������������������������������������������������������������������������30 3.2 Sediment Cores ......................................................................................................35 3.2.1 Southern Region ............................................................................................38 3.2.2 Northern Region ............................................................................................49 3.2.3 Central Region ..............................................................................................61 3.3 Acoustic Properties of Rex Lake ............................................................................92 3.3.1 Subsurface Seismic Facies ............................................................................92 3.3.2 Whole Cores Acoustic Properties .................................................................92 3.3.3 Surficial Sediment Acoustic Properties .........................................................98 IV. DISCUSSION ............................................................................................................106 4.1 Sediment Dispersal Processes ..............................................................................106 4.2 Subsurface Facies Analysis ..................................................................................109 4.3 Grain Size Analysis ..............................................................................................114 4.4 Historical Changes ...............................................................................................122 4.4.1 Pre-settlement Period (Prior to 1805) .........................................................124 4.4.2 Settlement Period (1805-1900) ...................................................................126 4.4.3 Recreation Period (1900-1980) ...................................................................128 4.4.4 Environment Regulation Period (1980-2014)