Pneumatic Slug Testing



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 or vacuum is used to change the static water level. As air pressure in the well is increased or decreased, the water level changes 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 or vacuum. The water level recovers 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 or 1.5 in. rods. Kit includes the pneumatic manifold, gauges, rod adapters, pressure transducer, data logger that adapts to the user’s PC, and a hand pump for applying air pressure or vacuum to the well head.

slug_test_jed[1]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 minutes, and all of the equipment needed is easily transported from one location 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

slug_test_carry[1]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 :

  • Slug Testing with the 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:

  • Newly revised 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, pressure and vacuum gauges necessary to quickly and easily conduct pneumatic slug tests.
  • The kit includes adapters for performing slug tests in Geoprobe®  25 in., and 1.5 in. probe rods.
  • The small diameter pressure transducer allows for slug tests in probe rods and PVC casing as small as 12,7mm (0.5 in) ID.
  • The Slug Test Data Logger enables use of sampling rates of 1, 2 and 10 Hertz to meet requirements for low-K formations and high-K formations producing oscillatory responses.
  • A simple hand pump supplies air pressure or vacuum as 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 diameter of many DP groundwater tools, minimal development water is generated.
  • The entire system can be stored and transported in its carrying case which measures 70 x 41 x 18 cm and weighs about 13.5 Kg.
  • 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, Port Hueneme – Californie

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 used to conduct slug-in as well as slug-out tests. The system provided real-time pressure transducer monitoring during the pumping tests.

Plus… New V2.0 Software Now Available for Slug Test Analysis .

Slug Test Analysis Soft

A new Instruction Bulletin (MK3181) with complete operating instructions and additional transducer and data logger specifications is available on

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