The Illinois Water Science Center has increased its sampling capabilities for hydrologic investigations by purchasing a Geoprobe™ system. This mobile unit, mounted on a truck chassis, is capable of obtaining soil, soil-gas, and ground-water samples using "direct push" technology. Push-rods are advanced into the ground by using the static weight of the truck combined with percussion energy. The Geoprobe is capable of obtaining samples at depths of 100+ feet under certain geologic conditions and tool assemblies. Hole diameters generally are from 0.5 to 1.5 inches, with 2-inch diameters possible in some cases. Continuous soil cores, temporary wells, piezometers, soil-gas implants, ground-water levels, ground-water samples, and slug tests are some of the investigative tasks that can be completed with the Geoprobe.
Advantages of using the Geoprobe over conventional drilling and sampling technologies include ease of mobilization, faster sample collection, and ease of equipment decontamination. Ground-surface disturbance is minimal because the direct push technology does not produce drill cuttings. Ground-water samples obtained with the Geoprobe generally are used for screening purposes, however their use for selected regulatory analyses is approved by the U.S. Environmental Protection Agency.
The Illinois Geoprobe system is self-contained in a 4-wheel drive "dually" truck, making difficult off-road sampling possible. The truck comes complete with sampling tools and water-storage capability. Since 2001, the Geoprobe has been used to collect soil and ground-water samples, and install temporary wells and piezometers for hydrologic investigations of the Illinois Water Science Center, as well as Water Science Centers elsewhere in the Northeastern, Southeastern, and Central Regions of the U.S. Geological Survey.
The Illinois Geoprobe, supporting equipment, and operators are available for hydrologic investigations of the U.S. Geological Survey and its cooperating public partners. Additional information concerning the Illinois Geoprobe system and its capabilities is available from:
Patrick Mills
Hydrologist
U.S. Geological Survey
1201 W. University Ave., Suite 100
Urbana, Illinois 61801
Telephone: (217) 328-9724
Fax: (217) 344-0082
Email: pcmills@usgs.gov
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