...............................................................................................................................................^ 1 Inlroduction.............................................................................................................................................^ 1 Purpose and scope....................................................................................................................................................... 3 Acknowledgments....................................................................................................................................................... 3 Geology................................................................................................................................................................................. 3 Hydrology............................................................................................................................................................................. 14 Water levels................................................................................................................................................................. 19 Flowmeter logging...................................................................................................................................................... 19 Results of tracer testing......................................................................................................................................................... 22 Summary and conclusions .................................................................................................................................................... 27 References cited.................................................................................................................................................................... 28 Appendixes 1-3: 1. Summary of data collected during the tracer test Water-level data from selected wells.......................................... 30 2. Summary of data collected during the tracer test Barometric pressure data............................................................ 44 3. Summary of data collected during the tracer test Water-level data corrected for fluctuations in barometric pressure.................................................................................................................................................. 46 FIGURES 1-2. Maps showing: 1. Location of the study area and monitoring wells, near Byron, Illinois............................................................ 2 2. Generalized geologic column showing stratigraphy, geohydrologic units, and median primary porosity of Ordovician and Quaternary deposits, near Byron, Illinois......................................................... 4 3-8. Diagrams showing: 3. Natural-gamma log, lithologic log, and generalized stratigraphic section for well MW2, near Byron, Illinois............................................................................................................................................... 6 4. Natural-gamma, acoustic-televiewer, and flowmeter logs; stratigraphy; and transmissivity in the test intervals isolated with a packer assembly for well SPW, near Byron, Illinois ...................................... 7 5. Natural-gamma, acoustic-televiewer, and flowmeter logs; stratigraphy; and transmissivity in the test intervals isolated with a packer assembly for well PZ1, near Byron, Illinois ....................................... 8 6. Natural-gamma, acoustic-televiewer, and flowmeter logs, and stratigraphy for well PZ2, near Byron, Illinois............................................................................................................................................... 9 7. Natural-gamma, acoustic-televiewer, and flowmeter logs, and stratigraphy for well PZ3, near Byron, Illinois............................................................................................................................................... 10 8. Natural-gamma, acoustic-televiewer, and flowmeter logs; stratigraphy; and transmissivity in the test intervals isolated with a packer assembly for well AW1S, near Byron, Illinois.......................................... 11 9. Map showing water-table altitude, fracture traces, and lines of geologic section, near Byron, Illinois, JulyS, 1993................................................................................................................................................ 12 10-13. Diagrams showing: 10. Geologic section, A-A" near Byron, Illinois.................................................................................................... 13 11. Velocity tomograms between wells AW1S-PZ2, PZ2-PZ3, and PZ3-SPW, near Byron, Illinois ................. 17 12. Attenuation tomograms between wells AW1S-PZ2, PZ2-PZ3, and PZ3-SPW, near Byron, Illinois............ 18 13. Concentration of bromide ion in water pumped from well SPW during the tracer injection phase of the tracer test, near Byron, Illinois, July 12-14, 1993........................................................................................ 26 TABLES 1. Summary of data for inclined fractures identified during acoustic-televiewer logging, near Byron, Illinois.......... 15 2. Summary of reflector data identified during single-hole directional reflection surveys, and fracture data obtained during acoustic-televiewer surveys, near Byron, Illinois................................................................ 16 3. Monitoring well and water-level data, near Byron, Illinois...................................................................................... 20