USING SHALLOW GEOPHYSICAL METHODS TO LOCATE A BURIED STREAM CHANNEL AT A STREAM RESTORATION SITE IN THE BURD RUN WATERHED, SHIPPENSBURG, PA By Neal P. Kerrigan A Thesis Submitted to the Department of Geography and Earth Science and the Graduate Council in partial fulfillment of the requirements for the degree of Masters of Science of Geoenvironmental Studies SHIPPENSBURG UNIVERSITY Shippensburg, PA December, 2013 ii SHIPPENSBURG UNIVERSITY Shippensburg, Pennsylvania This thesis submitted by Neal P. Kerrigan has been approved as meeting the research requirements for the Masters of Science in Geoenvironmental Studies degree. _______________ ______________________________________________ Date Dr. Joseph T. Zume Chairperson of Thesis Committee Associate Professor of Geography and Earth Science _______________ ______________________________________________ Date Dr. Thomas P. Feeney Professor of Geography and Earth Science _______________ ______________________________________________ Date Dr. Sean R. Cornell Associate Professor of Geography and Earth Science iii TABLE OF CONTENTS Acknowledgments…………………………………………………………….….…........x Abstract…………………………………………………….……………….….………...xi Chapter I: Introduction…………………………………………………….…….....................…..…1 1.1 Background...………………………………………………….....…......…1 1.2 Scope of the Study……..……………………………………...…….....….2 1.3 Research Questions…...………………………………………..…..….......3 Chapter II: The Study Area……………………………………….………….…....……4 2.2 A Brief Description of the Study Site…….……………………...…….....4 2.1.1 Climate………………………………………………………...….…....…6 2.2 Study Site Geology…………………………... ……………….……..…..7 2.2.1 Physiography and Structural Geology…………………...….…….….…..7 2.2.2 Geomorphology and Karst Development……………......……..….…....10 2.2.3 Implications for this Geophysical Investigation…..…….…..……...…...11 2.3 Soils………...….…………………………………………………….….11 2.4 Hydrology ……………………………………………………………....14 Chapter III: Literature Review…………………………………………………….….19 3.1 Review of Geophysical Methods…………………………………..…....19 3.1.1 Electrical Resistivity (ER)…………………………...….……………....19 3.1.2 Electromagnetic Methods (EM)……...……………………….………....24 3.1.3 Ground Penetrating Radar (GPR)……...……………….……………….28 Chapter IV: Methodology……………………………………………………………...30 4.1 Preliminary Site Assessment…………………..…………….………..….30 4.1.1 Locating the Buried Stream Channel……………………….….………...30 4.1.2 Topographic Survey……………………………..……………….……....32 4.1.3 Soil Sample Collection………………………….………………….…....35 4.2 Data Collection……….…………………….…………………………....42 4.2.1 Electrical Resistivity (ER)………………………………….…………....42 4.2.2 Ground Penetrating Radar (GPR)………………………………….…….43 4.2.3 Electromagnetic Induction (EM)……………………………….………..45 Chapter V: Analysis and Results…………………….………………………………...48 5.1 Introduction…...…………….……………………..……………………..48 5.2 Electromagnetic Survey…………..………….…………………………..48 5.3 Electrical Resistivity Survey………..…….……………………………...51 5.4 Ground Penetrating Radar…….………………...………………………..56 5.5 Integrated Results……………………….……………………………......64 iv Chapter VI: Summary and Conclusions……………………………………….……..67 6.1 Electromagnetic (EM) Survey…….……………..………………………67 6.2 Electrical Resistivity (ER) Survey…………….…………..……………..68 6.3 Ground Penetrating Radar (GPR) Survey………………….…………….69 6.4 Conclusion……………....………………………..……………………...70 6.5 Suggested Future Research……….…………………...…………...…….71 References………………………………………………………………………...…..…73 Appendix A……………………………………………………………………….....…..77 Appendix B……………………………………………………………………...…..…..80 Appendix C……………………………………………………………………...…..…..86 Appendix D………………………………………………………………..……...……..94 Appendix E…………………………………………………………………….....……..99 List of Figures Figure 2.1: Shippensburg Park (a) following and (b) before the restoration of Burd Run…………………………………………………………………...5 Figure 2.2: Average mean monthly precipitation (in millimeter) for Shippensburg, PA……………………………………………………..6 Figure 2.3: Shaded Relief map of PA showing the major physiographic provinces. ….……………………………………………………………………...7 Figure 2.2: A modified portion of a bedrock geology map within the Shippensburg Area. ………...………………………………………....9 Figure 2.5: The soils of the study site include Melvin Silt Loam (Me), Monongahela Silt Loam (Mna), Huntington Silt Loam (HuA), and Hagerstown Silt Loam (HcC)………………..………………………12 Figure: 2.6: Potential sources of alluvial material at Shippensburg Township Park………………………………………………………………….13 Figure 2.7: Meandering in Burd Run prior to restoration looking southeast…….15 Figure 2.8: Two cross-sections from the Burd Run channel prior to restoration..15 v Figure 2.9: Coarse-grained cobbles creating riffles in former channel prior to restoration……..…………………………………………………..…16 Figure 2.10: The southern banks of Burd Run experiencing slumping prior to restoration.…………………………………………………………17 Figure 2.11: The excavation of the current channel (foreground) and the pile of excavated material used to infill the former channel (background)...18 Figure 3.1: Electrical resistivity array showing current propagation in the earth..20 Figure 3.2: The Wenner Array for an electrical resistivity survey………………21 Figure 3.3: The Schlumberger Array for an electrical resistivity survey………..22 Figure 3.4: The Dipole-Dipole Array……………………………………………23 Figure 4.1: The edge of the fill material where the former channel is exposed…30 Figure 4.2: The old and present-day courses of Burd Run.……………………...31 Figure 4.3: Survey transects relative to the buried channel……………………...32 Figure 4.4: Topographic transects shown in the UTM 18⁰N NAD1983 Conus Cors96 coordinate system………………………………...………...33 Figure 4.5: Variations in elevation along transect 1-5 as collected by a Topcon GTS 223 total station (oriented northeast to southwest)……….…….34 Figure 4.6: Contour map (produced in ArcGIS10) of the Burd Run study site based on measured elevation points along occupied transect…….….35 Figure 4.7: Soil sample locations represented by letters A-F……………………36 Figure 4.8: Soil sample at C……………………………………………………...37 Figure 4.9: Soil sample compared to a picture of the soil sample at location B…39 Figure 4.10: Model of subsurface composition (depth in cm)…………………...40 Figure 4.11: The setup of the OhmMapper system with one receiver…………...42 Figure 4.12: The 100 MHz GPR antenna being towed on a sled………………..44 Figure 4.13: The 250 MHz antenna being pushed on a cart……………………..45 vi Figure 4.14: The EMP400 used at the study site………………………………...46 Figure 5.1: Conductivity anomalies under saturated soil conditions, created with; a.) Surfer 10, and b.) ArcGIS 10 software…………………………..49 Figure 5.2: Conductivity anomalies under less saturated soil conditions, created with; a.) Shepard interpolation in Surfer 10, and b.) IDW interpolation in ArcGIS 10 software. ………………………………51 Figure 5.3: a.) Raw apparent resistivity data, b.) calculated apparent resistivity and c.) interpreted inverse model resistivity results for transect 1....54 Figure 5.4: a.) Raw apparent resistivity data, b.) calculated apparent resistivity and c.) interpreted inverse model resistivity results for transect 2….54 Figure 5.5: a.) Raw apparent resistivity data, b.) calculated apparent resistivity and c.) interpreted inverse model resistivity results for transect 3….54 Figure 5.6: a.) Raw apparent resistivity data, b.) calculated apparent resistivity and c.) interpreted inverse model resistivity results for transect 4….55 Figure 5.7: a.) Raw apparent resistivity data, b.) calculated apparent resistivity and c.) interpreted inverse model resistivity results for transect 5….56 Figure 5.8: Interpreted GPR radargrams using a.) the 100 MHz and b.) the 250 MHz antennae along transect 1…………………………………......57 Figure 5.9: A comparison in shape between a.) Cross-section 19-E (Herrmann 1999) and b.) the channel anomaly detected in the 250 MHz radargram from transect 1….……………………………………………………60 Figure 5.10: Interpreted GPR radargrams using a.) the 100 MHz and b.) 250 MHz antennae along transect 2…………………………………………..61 Figure 5.11: Interpreted GPR radargrams using a.) the 100 MHz and b.) 250 MHz antennae along transect 3…………………………………………..62 Figure 5.12: Interpreted GPR radargrams using a.) the 100 MHz and b.) 250 MHz antennae along transect 4…………………………………………..62 Figure 5.13: Interpreted GPR radargrams using a.) the 100 MHz and b.) 250 MHz antennae along transect 5…………………………………………..63 Figure 5.14: A comparison of interpreted results of a.) the final resistivity model and b.) the 250 MHz GPR antenna for transect 1………………….64 vii Figure 5.15: A comparison of the results from a.) EM, and b.) ER and GPR (250MHz antenna for transect 1…………...………………………65 List of Figures in the Appendix A1: Cross-section 12-Burd Run………………………………………………….78 A2: Cross-section 13-Burd Run………………………….………………………78 A3: Cross-section 18B-Burd Run………………………………………………..78 A4: Cross-section 19E-Burd Run………………………………………………..79 B1: Inverse distance weighted (IDW) …………………………………………...81 B2: Natural Neighbor ……………………………………………………………82 B3 Minimum Curvature………………………………………………………….83 B4: Kriging………………………………………………………………………84 B5: Modified Shepard (Chosen interpolation method..………………………….85 C1: ER Results on Transect 1……………………………………………………87 C2: ER Results on Transect 2……………………………………………………87 C3: ER Results on Transect 3……………………………………………………88 C4: ER Results on Transect 4……………………………………………………88 C5: ER Results on Transect 5……………………………………………………89 C6: GPR radargram using a 100MHZ antenna along transect 1………………...89 C7: GPR radargram using a 100MHZ antenna along transect 2………………...90 C8: GPR radargram using a 100MHZ antenna along transect 3………………...90 C9: GPR radargram