Geoprobe® Systems developed the GW1600 Pneumatic Slug Test Kit for use with Geoprobe® brand groundwater sampling, profiling, and monitoring tools to conduct pneumatic slug tests in saturated formations of unconsolidated soils or sediments. The system provides high-quality data for accurate determination of formation hydraulic conductivity (K). The slug test kit is self-contained and is easily taken from site to site.  In pneumatic slug testing, the well head is sealed and air pressure is used to displace/lower the water level.  As air pressure in the well is increased, the water level falls until the water pressure "up" and the air pressure "down" are equal.  Once the water level is stable, a release valve is quickly opened, instantaneously releasing the air pressure.  The water level recovers (rising head test) without splashing and the pressure transducer and data logger/computer record the changes in water level and time.

The kit includes everything you will need for slug testing in screens installed with Geoprobe® 1.25, 1.5 or 2.25 in. rods.  Kit includes a pressure manifold and rod adapters, small diameter high resolution pressure transducer, data logger that adapts to the user's PC, and a pressure pump for applying air pressure to the top of the casing.

	Hydraulic conductivity is an important parameter in contaminant investigations. Hydraulic conductivity (K) is useful in determining the volume of water passing through a given soil cross section, and for estimating the flow velocity of contaminated groundwater. With the GW1600 Pneumatic Slug Test Kit, set-up is simple, requires only a few mintes, and all of the equipment needed is easily transported from one site to another.
	“There were some surprised looks when I went on site with the slug test kit because of its size! It was a simple process and it was easy to use.” Dave Fisch • Fisch Environmental • Valley Springs, CA

		Stephen Bartlett, with the University of Connecticut, conducts a slug test using the Geoprobe® Pneumatic Slug Test System at the Naval Facilities Engineering Service Center test site in Port Hueneme, CA.
	The Pneumatic Slug Test Kit (GW1600) includes all of the essential assemblies, adapters, and accessories to prepare you for measuring hydraulic conductivity with Geoprobe® groundwater samplers in the field. The kit is self contained and is easy to move from site-to-site.

Specific Slug Testing Applications... Learn more here.

• Slug Testing with the SP15 or SP16 Groundwater Sampler
• Slug Testing Fine Grained Formations

“We used the Pneumatic Slug Test System with direct push rods and also hooked it up to small diameter wells. The results were very informative and allowed us to progress to the next phase of the project with very useable information.” Tom Palaia • CH2M Hill • Denver, CO

Other features of the system include:

• Slug Test Acquisition Software (CD) is installed on your laptop computer for real-time observation of field tests and for data storage.
• The pneumatic manifold assembly includes valves, a pressure regulator, and pressure gauge necessary to quickly and easily conduct pneumatic slug tests.
• The kit includes adapters for performing slug tests in Geoprobe® 1.25 in., 1.5 in., and 2.25 in. probe rods.
• The small diameter pressure transducer allows for slug tests in probe rods and PVC casing as small as 0.5 in. (12.7 mm) ID.
• The Slug Test Data Logger enables use of sampling rates of 1, 2, 10 and 38 Hertz to meet requirements for low-K formations and high-K formations producing oscillatory responses (K>500 ft/day: 1.7x10-1 cm/sec).
• A simple foot pump supplies air pressure required to conduct the pneumatic tests in small direct push tools.
• A power inverter (included in the kit) lets you operate the entire system from your vehicle's auxiliary power outlet or power point.
• Because of the small well size, minimal development water is generated.
• The entire system can be stored and transported in its carrying case (29.8 lb./ 13.5 Kg) which measures 27.5 in. x 16 in. x 7 in. (699 x 406 x 178 mm).
• Optional adapters are available to conduct pneumatic slug tests in PVC casing from nominal 0.5- to 2.0 in. (12.7 to 50.8 mm) diameter.

ESTCP Study at Port Hueneme, CA
What influence does well construction have on determining hydraulic conductivity? This was the focus of a cooperative study conducted by Gary Robbins and Stephen Bartlett at the University of Connecticut, Mike Barcelona at Western Michigan University, and Mark Kram at the Naval Facilities Engineering Service Center (NFESC) in Port Hueneme, CA. The study, funded through the Environmental Security Technology Certification Program (ESTCP), entailed conducting slug tests and pumping tests in conventional and direct push wells. “We conducted over 300 tests in 13 days in 15 wells thanks to the Geoprobe® Pneumatic Slug Test Kit,” according to Gary Robbins, Professor for the Geology and Geophysics Department at the Univ. of CT. With the help of Wes McCall, Geoprobe® Environmental Geologist, the commercial system was readily modified to conduct slug-in as well as slug-out tests. The system provided real-time pressure transducer monitoring during the pumping tests.

Plus... Software Now Available for Slug Test Analysis [More...]

A free SOP with complete operating instructions and additional transducer and data logger specifications is available from Geoprobe® Systems, 1-800-436-7762. Or download now: Pneumatic Slug Test SOP (640 KB PDF).