USE OF A GEOPROBE DIRECT-PUSH DRILLING PLATFORM FOR GRADUATE AND UNDERGRADUATE EDUCATION AND RESEARCH IN HYDROGEOLOGY

In January 2007 the Department of Geology and Environmental Geosciences at Northern Illinois University acquired a Geoprobe© 6600 rig as part of a grant from the National Oceanic and Atmospheric Administration (NOAA) with the goal of improving the educational and research analytical capabilities of the department. The Geoprobe rig has been used by more than 25 students in educational settings (such as a Drilling Methods course at NIU and the Northern Illinois University/Illinois State University Environmental Geology Field Camp) and has supported research of three graduate and two undergraduate students.

For example, the Geoprobe© rig has been used at a research site by the student authors (two graduate and one undergraduate) to study the stratigraphy of and potential recharge pathways through a shallow aquifer along the Kishwaukee River on the edge of the NIU campus. The site is also being developed for use as a hydrogeologic teaching wellfield. The rig was used for a variety of methods including dual-tube sediment coring, electrical conductivity (EC) logging and piezometer installation. The EC logging is faster than sediment coring and was performed adjacent to a control sediment core for conductivity-to-grain size calibration to allow the efficient use of EC-only drilling locations as the wellfield expands. Cross-section development and water table analysis indicate that the outwash aquifer is continuous across the river valley and groundwater flow is toward the river. However, detailed logging of the sediment cores indicates that the aquifer is not a continuous unit of outwash sand and gravel that might be found in a proglacial braided-river system, but is a system of interconnected sand and gravel lenses partially separated by lower-permeability silt and clay lenses likely deposited by the post-glacial meandering river. The aquifer is of limited thickness so it is not likely a major pathway for recharge to deeper outwash and bedrock aquifers. Sediment grain size (sieve) analysis of selected intervals from the dual-tube cores will be used for Hazen Method estimations of hydraulic conductivity for comparison with slug test and pumping test results once the teaching wellfield is completed. Overall, the Geoprobe has been an invaluable hands-on teaching and research tool for both graduate and undergraduate students.